Disease :

Cholera is an acute diarrheal illness caused by certain serotypes of Vibriocholeriae. Infection is acquired by ingestion of contaminated food or water. The disease is toxin mediated and fever is unusual. The toxin acts on the intestinal epithelial cells of the small intestines, producing hyper secretion of water and chloride ion and thus leading to massive diarrhea upto 15 litres/day and may lead to profound hypovolumia.

Vaccine:

Two types of oral cholera vaccine have been developed. The first is killed whole cell (WC) vaccine. Two formulations of the killed WC vaccine have been prepared: one composed solely of killed bacteria while the other one also contains the non toxic. B supcervit of cholera toxin (WC/BS). Both the killed Cholera vaccines given orally, are safe and effective but WC/BS vaccine is proving better than WC vaccine. The inactivated or killed vaccine confers high-grade (85–90%) protection for 6 months after the second dose, to be given between 1-6 weeks after the first. After 3 years, protection remains as high as 62% in vaccine recipients over 5 years of age. In children between 2-6 years three doses of vaccines are given each separated by an interval of 1-6 weeks. Oral cholera vaccine is licensed for resident of or travellers to endemic or epidemic areas. Immunisation should be completed at least 1 week before potential exposure. However, there is no requirement for cholera vaccination for international travel. Immunisation with cholera vaccine does not provide complete protection and all the residents of or travellers to a country where cholera exists should be warned that scrupulous attention to food, water, and personal hygiene is essential. Live vaccine have been developed and is under field trails but none has been proved effective till date and thus are not recommended. Injectable cholera vaccine provides unreliable protection and is no longer recommended.

Disease :

Diphtheria is a bacterial disease caused by Corynebacterium diphtheriae. The infection commonly affects the throat and may lead to obstruction of the airways and death. Exotoxin-induced damage occurs to organs such as the heart. Nasal diphtheria may be mild, and chronic carriage of the organism frequently occurs; asymptomatic infections are common. Transmission is from person to person, through droplets and close physical contact, and is increased in overcrowded and poor socioeconomic conditions. A cutaneous form of diphtheria is common in tropical countries and may be important in transmission of the infection.

Vaccine:

Diptheria vaccines are prepared from the toxin of Corynebacterium diphtheriae and adsorption on aluminum hydroxide or aluminum phosphate improves anti-genicity. The vaccine stimulates the production of the protective antitoxin. Single-antigen diphtheria vaccine is not available and adsorbed diphtheria vaccine is given as a combination product containing other vaccines. For primary immunization of children aged between 2 months and 10 years vaccination is recommended usually in the form of 3 doses (separated by 1-month intervals) of diphtheria, tetanus, pertussis (whole or acellular component). In unimmunised individual aged over 10 years the primary course comprises of 3 doses of adsorbed diphtheria [low dose], tetanus. A booster dose should be given 3 years after the primary course (this interval can be reduced to a minimum of 1 year if the primary course was delayed). Children under 10 years should receive either adsorbed diphtheria, tetanus, pertussis vaccine or adsorbed diphtheria [low dose], tetanus, pertussis vaccine. Individuals aged over 10 years should receive adsorbed diphtheria [low dose] and tetanus vaccine. A second booster dose of adsorbed diphtheria [low dose] and tetanus vaccine should be given 10 years after the previous booster dose (this interval can be reduced to a minimum of 5 years if previous doses were delayed). Those intending to travel to areas with a risk of diphtheria infection is high should be fully immunized. If more than 10 years have lapsed since completion of immunization schedule, a dose of adsorbed diphtheria [low dose] and tetanus should be administered. Staff in contact with diphtheria patients or with potentially pathogenic clinical specimens or working directly with C. diphtheriae or C.ulcerans should receive a booster dose if fully immunized (with 5 doses of diphtheria-containing vaccine given at appropriate intervals); further dose should be given at 10 yrs interval if risk persists. Individuals at risk who are not fully immunized should complete the primary course, a booster dose should be given after 5 years and then at 10 year interval. Adsorbed diphtheria [low dose] and tetanus is used for this purpose; immunity should be checked by antibody testing at least 3 months after completion of immunization.

Disease :

Haemophilus influenzae type b (Hib) is a common cause of bacterial pneumonia and meningitis and of a number of other serious and potentially life-threatening conditions, including epiglottitis, osteomyelitis, septic arthritis and sepsis in infants and older children.

Vaccine:

Haemophilus influenzae type b (Hib) vaccine is made from capsular polysaccharide; and is available as single agent preparation for use in children, who did not receive it as a part of routine immunized programme. It is also conjugated with a protein such as tetanus toxoid to increase immunogenicity, especially in young children. Hib vaccines are also available as combination vaccines as DTP/Hib. DTPa/Hib, DTPa/IPV/Hib, DTP/Hep B/Hib, DTPa/Hep B/Hib, DTPa/IPV/Hep B/Hib. The studies using these combination vaccines show similar immune responses to all the components as compared to when given separately. Haemophillus influenzae type b vaccine is a component of the primary course of childhood immunization and is given along with diphtheria, tetanus, pertussis schedule. For infants under 1 year, the course consists of 3 doses of a vaccine containing haemophillus influenzae type b component with an interval of 1 months between doses. A booster dose of haemophilus influenzae type b vaccine should be given at around 12 months of age. Unimmunised children over 12 months need only 1 dose of Haemophilus influenzae type b vaccine. The risk of infection falls sharply in older children and the vaccine is not normally required for children over 10 years. Haemophilus influenzae type b vaccine may be given to those over 10 years who are considered to be at increased risk of invasive H.influenzae type b disease (such as those with asplenia, sickle cell disease, immunodeficiency states, nephrotic syndrome and complement deficiency.

Disease :

Although hepatitis A is rarely fatal in children and young adults, most infected adults and some older children become ill and are unable to work for several weeks or months. The case-fatality rate exceeds 2% among those over 40 years of age and may be 4% for those aged 60 years or more.

Vaccine:

Hepatitis A vaccines prepared from formaldehyde-inactivated hepatitis A virus grown in human diploid cells, are safe and effective.

Disease :

Acute viral Hepatitis is a systemic infection affecting the liver predominately. Infection with Hepatitis B virus is one of the commonest cause leading to hepatitis. Hepatitis B virus (HBV) is usually transmitted by inoculation of infected blood or blood products or by sexual contact (heterosexual and/or homosexual) and is present in saliva, semen and vaginal secretions. Hepatitis B virus infected mothers may transmit HBV infection to the neonates at delivery, the risk of chronic infection in infant is as high as 90%. Groups at risk include patients and staff hemodialysis centres, physicians, dentists, nurses and personnel working at clinical and pathological labrotaries and blood banks. A person with chronic Hepatitis B infection particularly when HBV infection is acquired early in life, is at high substantial risk of cirrhosis and hepato-cellular carcinoma.

Vaccine:

Hepatitis B vaccine contains inactivated hepatitis B virus surface antigen (HBsAg) adsorbed on aluminum hydroxide adjuvant. It is made biosynthetically using recombinant DNA technology. And the two types are equally safe and effective. The vaccine is used in individuals at high risk of contracting hepatitis B, which are as follows: parenteral drug misusers, their sexual partners, and household contacts; other drug misusers who are likely to progress to injecting. Individuals who change sexual partners frequently. Close family contacts of a case or carrier Babies whose mother have had acute hepatitis B during pregnancy or are positive for hepatitis B surface antigen (regardless of e-antigen markers) hepatitis B vaccination is started immediately on delivery and hepatitis B immunoglobulin given at the same time (but preferably at a different site). Babies whose mothers are positive for hepatitis B surface antigen and for e-antigen antibody should receive the vaccine only (but babies weighing 1.5 kg or less should also receive the immunoglobulin regardless of the mother’s e-antigen antibody status. Individuals, those receiving regular blood transfusions or blood products, and carers responsible for the administration of such products. Patients with chronic renal failure including those on haemodialysis. Haemodialysis patients should be monitored for antibodies annually and re-immunised if necessary. Home carers (of dialysis patients) should be vaccinated. Individuals with chronic liver disease Healthcare personnel (including trainees) who have direct contact with blood or blood stained body fluids or with patients tissues; Laboratory staff who handle material that may contain the virus. Other occupational risk groups such as morticians and embalmers Staff and inmates of custodial institutions Those traveling to areas of high or intermediate prevalence who are at increased risk or who plan to remain there for lengthy periods. Families adopting children from countries with a high or intermediate prevalence of hepatitis B Foster carers and their families. Immunisation may take up to 6 months to confer adequate protection and the duration of immunity is not known precisely, but a single booster 5 years after the primary course may be sufficient to maintain immunity for those who continue to be at risk. Immunisation does not eliminate the need for commonsense precautions for avoiding the risk of infection from known carriers by the routes of infection which have been clearly established. Accidental inoculation of hepatitis B virus infected blood into a wound, incision, needle-prick or abrasion may lead to infection whereas it is unlikely that indirect exposure to a carrier will do so. Specific hepatitis B immunoglobulin (HBIG) is available for use with the vaccine in those accidentally inoculated and in neonates at special risks of infection. Three doses of vaccine constitute the complete series; the first two doses are usually given 1 month apart, with the third dose 1–12 months later. Immunization provides protection for at least 15 years and, according to current scientific evidence, probably for life. Because of the prolonged incubation period of hepatitis B, some protection will be afforded to most travellers following the second dose given before travel, provided that the final dose is given upon return. A rapid schedule of administration of monovalent hepatitis B vaccine has been proposed by the manufacturer as follows: day 0; 1 month; 2 months. An additional dose is given 6-12 months after the first dose. A very rapid schedule of administration of monovalent hepatitis B vaccine has been proposed as follows: day 0; 7 days; 21 days. An additional dose is given at 12 months. A combination vaccine that provides protection against both hepatitis A and hepatitis B may be considered for travellers potentially exposed to both organisms. This inactivated vaccine is administered as follows: day 0; 1 month; 6 months. A rapid schedule at day 0, 1 month and 2 months, with an additional dose at 12 months, has been proposed by the vaccine manufacturer, as well as a very rapid schedule with administration at day 0, day 7 and day 21 with a booster dose at 12 months. Vaccination of persons who have doubtful history of immunization or adult population that have expected high rates of previous HBV infection, pre vaccination testing might reduce the cost by avoiding vaccination of persons who are already immune.

Disease :

Human papillomavirus (HPV) is a family of viruses that are very common all over the world. Although most HPV infections cause no symptoms and are selflimited, persistent genital HPV infection can cause cervical cancer in women (as well as other types of anogenital cancers, head and neck cancers, and genital warts in both men and women). Oncogenic HPV serotypes 16 and 18 account for 70% cases of cervical cancer. They have also been implicated in the causation of vulvar, vaginal, penile and oropharyngeal cancers. Nononcogenic HPV serotypes 6 and 11 are responsible for more than 90% of anogenital warts.

Vaccine:

Human papilloma virus vaccine is available as a bivalent vaccine or a quadrivalent vaccine. Both vaccines are licensed for use in females for the prevention of the cervical cancer and other pre-cancerous lesions caused by human papilloma virus types 16 and 18. In addition quadrivalent vaccine is licensed for use in females for the prevention of genital warts and pre-cancerous lesions caused by human papilloma virus types 6, 11, 16 and 18. The two vaccines are not interchangeable and one vaccine product should be used for an entire course. The vaccine is intended for use primarily in girls and young women for prevention of diseases caused by the HPV genotypes included in the vaccine. Human papilloma virus vaccine will be most effective if given before sexual activity starts and is recommended for administration to girls and young women before in the age of 9-45 years. The first dose is given to females aged 12 to 13 years, the second and the third doses are given 1-2 and 6 months after the first dose; all 3 doses should be given within a 12 month period. If the course is interrupted, it should be resumed but not repeated, allowing the appropriate interval between the remaining doses. The duration of protection has not been established, but current studies suggest that protection is maintained for at least 6 years after completion of the primary course. It will, however, take time to be able to measure duration of protection in terms of clinical efficacy and thus a booster dose is not recommended at present, based on follow up data of five to six years duration only. As the vaccines do not protect against all strains of human papilloma virus cervical screening should continue.

Disease :

Influenza is an acute respiratory illness cause by influenza viruses. The illness affects the upper and/or lower respiratory tract and is often accompanied by systemic signs and symptoms such as fever, headache, myelgia and weakness. Outbreaks of illness of variable extent and severity occur nearly every winter. Such outbreaks result in significant morbidity in general population and increased mortality rates among certain high risk patients mainly due to pulmonary complications.

Vaccine:

Inactivated and live attenuated vaccines against influenza A & B are available and their use is one of the major steps in the prevention of influenza. Influenza viruses constantly evolve, with rapid changes in their antigenic characteristics. To be effective, influenza vaccines need to stimulate immunity to the principal strains of virus circulating at the time. In a very limited number of countries, a live vaccine is being used. The internationally available vaccines contain three inactivated viral strains, with the composition being modified every 6 months to ensure protection against the strains prevailing in each influenza season. Since the antigenic changes in circulating influenza viruses occur very rapidly, there may be significant differences between prevailing strains during the influenza seasons of the northern and southern hemispheres, which occur at different times of the year. Vaccine composition is therefore adjusted for the hemisphere in which the vaccine will be used. Thus, a vaccine obtainable in one hemisphere may offer only partial protection against influenza infection in the other.

Disease :

Japanese B Encephalitis is an arbovirus which is transmitted in humans through mosquito bite. The incubation period is between 5-15 days. Though disease occurs in all ages but children are highly affected in endemic areas. The acute encephalitis usually lasts from few days to as long as 2-3 weeks but the recovery is very slow, with weeks or months required for the return of maximal recoupable function.

Vaccine:

This vaccine is recommended either for those living in endemic areas or during epidemics for travellers as aforementioned. Three types of JE vaccine are currently in large-scale production and use: inactivated mouse-brain-derived vaccine (IMB), cell-culture-derived inactivated vaccine and cell culture-derived live attenuated SA 14-14-2 vaccine. At present, the IMB vaccine is the most widely available commercially, but its production will cease in the near future. New vaccines are in the final stage of development. For children aged 1–3 years, the mouse-brain-derived vaccine provides adequate protection throughout childhood following two primary doses 4 weeks apart and boosters after 1 year and subsequently at 3-yearly intervals until the age of 10–15 years. Live attenuated SA14-14-2 vaccine gives equally good protection with a single dose followed, as required, by a single booster dose given at an interval of about 1 year Vaccine for travellers: Two doses inactivated vaccine or one dose of live attenuated vaccine is given before departure.

Disease :

Measles is a highly contagious infection; before vaccines became available, this disease affected most people by the time of adolescence. In 2005, measles still affected nearly 21 million persons, and the number of global measles deaths was estimated to be 345 000. Common complications include middle-ear infection and pneumonia. Transmission, which is primarily by large respiratory droplets, increases during the late winter and early spring in temperate climates, and after the rainy season in tropical climates.

Vaccine:

Though measles/mumps/rubella (MMR) or measles/rubella (MR) is being given in many countries instead of monovalent vaccine but in many developing countries monovalent measles vaccine is being advocated. Measles vaccination is usually given after the age of 9 months, preferably between 12-15 months. In developing countries measles vaccination is being given at the age of 9 months. To ensure optimum population immunization it is being advocated now that a second dose of measles vaccine may be given at the school entry (between 4-6 years). However in cases of outbreak the vaccine can be given to infants as young as six months old with a recommendation of second dose at 12-15 months. In our country due to high incidence of measles first dose is given at the age of 9 months and second dose between 16-18 months. Vaccination of susceptible adults within 72 hours of exposure to active case of measles is protective . Special attention must be paid to all children and adolescent travellers who have not been vaccinated against measles at the appropriate time. While traveling to measles endemic areas, the aforementioned children and adolescent should be immunized properly.

Disease :

Neisseria meningitis is the etiologic agent of two life-threatening disease: meningococcal meningitis and fulminant meningococcemia. More rarely, meningococcal causes pneuomonia, septic arthritis, pericarditits, urethritis and conjunctivitis. Most cases are potentially preventable by vaccination. The disease is transmitted by droplet infection. Up to 40% of the persons are nasopharyngeal carriers of meningococcal, but disease develops in relatively few of these persons. Disease is characterized by high fever, chills, headache, backache, abdominal and extremity pains, nausea and vomiting being typical features. Rapidly developing confusion, delirium,scizures and coma occur in some.

Vaccine:

nternationally marketed meningococcal polysaccharide vaccines are either bivalent (A and C) or tetravalent (A, C, Y and W-135).The vaccines are purified, heat stable, lyophilized capsular polysaccharides from meningococci of the respective serogroups. Both group A and group C vaccines have documented short-term efficacy levels of 85–100% in older children and adults. However, group C vaccines do not prevent disease in children under 2 years of age, and the efficacy of group A vaccine in children under 1 year of age is unclear. Group Y and W-135 polysaccharides have been shown to be immunogenic only in children over 2 years of age. Vaccine is given as a single dose subcutaneously and the protective antibodies response occurs within 10-14 days of vaccination. In school-children and adults, the bivalent and tetravalent polysaccharide vaccines appear to provide protection between 3-5 years, but in children under 4 years the levels of specific antibodies decline rapidly after 2–3 years. Thus it is advisable to give two doses of vaccine at an interval of three months to children below the age of two years. A booster dose is given after five years in each group to maintain immunity. The currently available bivalent and tetravalent meningococcal vaccines are recommended for immunization of specific risk groups as well as for large-scale immunization, as appropriate, for the control of meningococcal outbreaks caused by vaccine-preventable serogroups (A and C, or A, C, Y, W-135 respectively). Travellers who have access to the tetravalent polysaccharide vaccine (A, C, Y, W-135) should opt for this rather than the bivalent vaccine because of the additional protection against groups Y and W-135. These vaccines do not provide any protection against group B meningococci, which are the leading cause of endemic meningococcal disease in some countries.

Disease :

A combined live measles, mumps, and rubella vaccine (MMR vaccine) is being widely used instead of monovalent vaccines with an aim to eliminate measles, mumps, and rubella (and congenital rubella syndrome). Every child should receive two doses of MMR vaccine by entry to primary school, unless there is a valid contra-indication (see below). MMR vaccine should be given irrespective of previous measles, mumps or rubella infection.

Vaccine:

The first dose of MMR vaccine is given to children aged more than 12 months (between 12-18 months). A second dose is given before starting school at 3-5 years of age. When protection against measles is required urgently (e.g. during a measles outbreak), the second dose of MMR vaccine can be given 1 month after the first dose. Children presenting for pre-school booster who have not received the first dose of MMR vaccine should be given a dose of MMR vaccine followed 3 months later by a second dose. At school-leaving age or at entry into further education, MMR immunization should be offered to individuals of both sexes who have not received both doses. In a young adult who has received only a single dose of MMR in childhood, a second dose is recommended to achieve full protection. MMR vaccine should be used to protect against rubella in seronegative women of child-bearing age. Vaccination should never be given during pregnancy and pregnancy should be avoided during one month of vaccination. MMR vaccine may also be offered to previously unimmunised and seronegative post-partum women. Vaccination a few days after first delivery is important because about 60% of congenital abnormalities from rubella infection occur in babies of women who have borne more than one child. MMR vaccine may also be used in the control of out breaks of measles and should be offered to susceptible; children aged over 6 months who are contacts of a case, within 3 days of exposure to infection; these children should still receive routine MMR vaccinations at the, recommended ages. Household contacts of a case, aged between 6 and 9 months may receive normal immunoglobulin. MMR vaccine is not suitable for prophylaxis following exposure to mumps or rubella since the antibody response to the mumps and rubella components is too slow for effective prophylaxis. Children and adults with impaired immune response should not receive live vaccines. If they have been exposed to measles infection they should be given normal immunoglobulin.

Disease :

Mumps, or parotitis epidemica, is a viral infection that primarily affects the salivary glands. Although mumps is mostly a mild childhood disease, the virus may also affect adults, in whom complications such as meningitis and orchitis are relatively common. Encephalitis and permanent neurological sequelae are rare complications of mumps.

Vaccine:

The mumps vaccine is usually given in combination with measles and rubella vaccine (MMR). Different attenuated strains of the mumps virus are used for the production of live mumps vaccines, all of which are considered safe and efficacious, except for the Rubini strain. In order to avoid possible interference with persistent maternal antibodies, the recommended one dose of the vaccine is usually given after the age of 9 months. A single dose of mumps vaccine, either as single antigen monovalent vaccine or in combination, (usually MMR) has a protective efficacy of 90–96%, and the second dose given in some countries at age 4–6 years provides protection to most individuals who do not respond to the first.

Disease :

Pertussis (whooping cough) is a highly contagious acute bacterial disease involving the respiratory tract and caused by Bordetella pertussis. It is transmitted by direct contact with airborne discharges from the respiratory mucous membranes of infected persons. It causes a severe cough of several weeks’ duration with a characteristic whoop, often with cyanosis and vomiting. In young infants, the cough may be absent and disease may manifest with spells of apnoea. Although pertussis can occur at any age, most serious cases and fatalities are observed in early infancy and mainly in developing countries. Major complications include pneumonia, encephalitis and malnutrition (due to repeated vomiting). Vaccine is the most rational approach to pertussis control.

Vaccine:

In contrast to diphtheria and tetanus vaccines which are toxoid, pertussis vaccine is derived from inactivated bacteria. Whole cell pertussis vaccine (wP) is suspension of killed B pertussis inactivated by formalin. Whole cell pertussis became unpopular due to various adverse events though unauthenticated. Thereafter attempts of developing acellular pertussis vaccine (aP) were initiated. In past decade significant progress has been made in the development of pertussis vaccine. As compared to whole cell pertussis vaccine, the cellular pertussis vaccine is acellular associated with less significant reactions. Pertussis vaccine is usually given as a combination preparation containing other vaccines like tetanus and/or diphtheria. For the routine immunization of infants, primary immunization with pertussis (whooping cough) vaccine is recommended in the form of 3 doses (separated by 1 month intervals) of diphtheria, tetanus, pertussis. A booster dose should be given 3 years after the primary course. All travellers should be up to date with the vaccine. Both whole-cell (wP) and acellular (aP) pertussis vaccines provide excellent protection.

Disease :

The term “pneumococcal disease” refers to a group of clinical conditions caused by the bacterium Streptococcus pneumoniae. Invasive pneumococcal infections include pneumonia, meningitis and febrile bacteraemia; the common non-invasive conditions include otitis media, sinusitis and bronchitis. Infection is acquired by direct person-to-person contact via respiratory droplets or oral contact. There are many healthy, asymptomatic carriers of the bacteria, but there is no animal reservoir or insect vector. Several chronic conditions predispose to serious pneumococcal disease. Increasing pneumococcal resistance to antibiotics underlines the importance of vaccination.

Vaccine:

Pneumococcal vaccines are directed against Streptococcus pneumoniae (pneumococcus); the vaccines contain polysaccharide from capsular pneumococci. Pneumococcal polysaccharide vaccine contains purified polysaccharide from 23 capsular types of pneumococci (PPV-23) whereas pneumococcal polysaccharide conjugate vaccine (adsorbed) contains polysaccharide from 7 capsular types (PCV-7), the polysaccharide being conjugated to protein. The conjugate vaccine is effective in young children.

Disease :

Poliomyelitis is a disease of the central nervous system caused by three closely related enteroviruses, poliovirus types 1, 2 and 3. The virus is spread predominantly by the faeco–oral route, although rare outbreaks caused by contaminated food or water have occurred. After the virus enters the mouth, the primary site of infection is the intestine, although the virus can also be found in the pharynx. In developing countries, 60–70% of cases currently occur in children under 3 years of age and 90% in children under 5 years of age. The resulting paralysis is permanent, although some recovery of function is possible. There is no cure.

Vaccine:

There are two types of poliomyelitis vaccine, inactivated poliomyelitis vaccine and live (oral) poliomyelitis vaccine. Oral polio vaccine is being used as a part of global immunization programme especially in developing countries; whereas injection of polio vaccine containing inactivated strains of human poliovirus types 1, 2 and 3 is being used in developed countries. A course of primary immunization consists of 3 doses starting at 2 months of age with intervals of 1 month between doses. Two booster doses of a preparation containing inactivated poliomyelitis vaccine are recommended, the first before school entry and the second before leaving school. Further booster doses are only necessary for adults at special risk, such as travellers to endemic areas, or laboratory staff likely to be exposed to the viruses, or healthcare workers in possible contact with cases; booster doses should be given to such individuals every 10 years. The live (oral) vaccine poses a very rare risk of vaccine-associated paralytic polio because the attenuated strain of the virus can revert to a virulent I form. For this reason the live (oral) vaccine must not be used for immunosuppressed individuals or their household contacts. The use of inactivated poliomyelitis vaccine removes the risk of vaccine-associated paralytic polio altogether. Now a days preparations containing macfoaided poliomyelitis vaccine are being used in place of oral polio vaccine or to complete an immunization course with one polio vaccine. Some persons advocate the use of both oral as well injectable vaccine in developing countries. Travellers: Unimmunised travellers to areas with a high incidence of poliomyelitis should receive a full course of a preparation containing inactivated poliomyelitis vaccine. Those who have not been vaccinated in the last 10 years should receive a booster dose of adsorbed diphtheria [low dose], tetanus and inactivated poliomyelitis vaccine. Vaccine There are two types of vaccine: inactivated (IPV), which is given by injection, and oral (OPV). OPV is composed of the three types of live attenuated polioviruses. Because of the low cost and ease of administration of the vaccine and its superiority in conferring intestinal immunity, OPV has been the vaccine of choice for controlling epidemic poliomyelitis in many countries. On very rare occasions (2–4 cases per million births per year) OPV causes vaccine-associated paralytic poliomyelitis (VAPP). The risk of VAPP is higher with the first dose of OPV than with subsequent doses. VAPP is more common in individuals who are immunocompromised, for whom IPV is the vaccine of choice. Most industrialized countries now use IPV, either as the sole vaccine against poliomyelitis or in schedules combined with OPV. Although IPV suppresses pharyngeal excretion of wild poliovirus, this vaccine has only limited effects in reducing intestinal excretion of poliovirus. A course of primary immunization consists of 3 doses, starting at 2 months of age with interval of 1 month between doses. In India no booster dose is required after the age of 5 years where as in developed or polio free countries booster doses are required first before school entry and second before leaving school. Unvaccinated older children and adults also receive 3 doses, second dose after 1-2 months and third dose after 6-12 months after the 1st dose. IPV is the vaccine of choice to protect travellers with no history of OPV use, as well as for immuno compromised individuals, their contacts and family members. Travellers to polio-infected countries and areas who have received three or more doses of OPV in the past should be offered another dose of polio vaccine before departure. Any unimmunized individuals intending to travel to such areas require a complete course of vaccine. Countries differ in recommending IPV or OPV in these circumstances: the advantage of IPV is that any risk of VAPP is avoided, but this vaccine is more expensive and may not prevent faecal excretion of the virus. In order to limit further international spread of wild poliovirus to polio-free areas, travellers from a polio-infected country or area should have a full course of vaccination against polio preferably with OPV, before leaving their country of residence, with a minimum one dose of OPV before departure. Some polio-free countries may also require travellers from polio-infected countries to be immunized against polio in order to obtain an entry visa.

Disease :

Rabies is an acute viral disease of the central nervous system (CNS) that is transmitted to humans by infected animals. After a prodromal phase, rabies manifests most often as encephalitis – or less frequently as a paralytic form of the disease – and then progresses to coma and death. The disease is transmitted by infective saliva that gains entry into the body by an animal bite or sometime an open wound. The incubation period may range from 10 days to many years but is usually 3-7 weeks depending upon the distance of the wound from the CNS.

Vaccine:

Vaccination against rabies is used in two distinct situations: to protect those who are at risk of exposure to rabies, i.e. pre-exposure vaccination; to prevent clinical rabies occurrence after exposure has occurred, usually following the bite of an animal suspected of having rabies, i.e. post-exposure prophylaxis. The vaccines used for pre-exposure and post-exposure vaccination are the same, but the immunization schedule differs according to the type of application. Rabies immunoglobulin is used only for post-exposure prophylaxis. Modern vaccines of cell-culture or embryonated egg origin are safer and more effective than the older vaccines, which were produced in brain tissue. These modern rabies vaccines are now available in major urban centres of most countries of the developing world. Rabies immunoglobulin, on the other hand, is in short supply worldwide and may not be available even in major urban centres in many dog rabies-infected countries.

Disease :

Rotavirus causes an acute gastroenteritis in infants and young children and is associated with profuse watery diarrhoea, projectile vomiting and fever. Rapid dehydration can occur, especially in very young infants, requiring rehydration therapy. The virus is transmitted via the faeco–oral route and by direct person-to-person spread, although a respiratory mode of transmission has been proposed also. It replicates in the enterocytes of the small intestine, causing extensive damage to the microvilli that results in mal-absorption and loss of fluids and electrolytes.

Vaccine:

Rotavirus vaccine (live, oral) is licensed for immunization of infants over 6 weeks of age for protection against gastro-enteritis caused by rotavirus infection. Immunization is started between the age of 6-12 weeks, neither earlier than 6 weeks nor later than 12 weeks. Two to three doses are given at an interval of 1-2 months. Rotavirus vaccine is contra-indicated in individuals with immunodeficiency and in those predisposed to, or with a history of intussusception. The administration of rotavirus vaccine should be postponed in infants with diarrhoea or vomiting. The rotavirus vaccine virus is excreted in the stool and may be transmitted to close contacts; the vaccine should be used with caution in those with immunosuppressed close contacts. Carers of a recently vaccinated baby should be advised of the need to wash their hands after changing the baby's nappies. To date, the clinical efficacy of the rotavirus vaccines has been demonstrated mainly in the Americas and in Europe. WHO recommends the inclusion of rotavirus vaccination into the national immunization programmes of regions where vaccine efficacy data suggest a significant public health impact. Vaccination is not currently recommended for travellers or older children outside the routine childhood immunization schedule.

Disease :

Rubella occurs worldwide and is normally a mild childhood disease. However, infection during early pregnancy may cause fetal death or congenital rubella syndrome which is characterized by multiple defects, particularly of the brain, heart, eyes and ears. CRS is an important cause of hearing and visual impairment and mental retardation in countries where acquired rubella infection has not been controlled

Vaccine:

The internationally licensed rubella vaccines, based on live attenuated RA 27/3 strain of the rubella virus and propagated in human diploid cells, have proved to be safe and efficacious. Following well designed and implemented programmes using such vaccines, rubella and congenital rubella syndrome have almost disappeared from many countries. Other attenuated vaccine strains are available in Japan and China. Rubella vaccine is commercially available in a monovalent form, in a bivalent combination with either measles or mumps vaccine, and in the trivalent Measles/Mumps/Rubella (MMR) vaccine. Rubella vaccine should be used to protect against rubella in seronegative child bearing age. Vaccination should never be given during pregnancy and pregnancy has to be avoided within one month of vaccination. Vaccine should be especially offered to previously unimmunised and seronegative post partum women. Vaccination within few days after 1st delivery is important because about 60% of congenital abnormalities from rubella infection occur in babies of women who have borne more than one child.

Disease :

Swine flu is a contagious respiratory disease that normally only affects pigs. It is commonly caused by H1N1 strains of influenza A virus but other strains also circulate in pigs. Normally human gets infected after close contact with infected pigs. But a new strain of swine flu has emerged in March/April 2009 in Mexico which can spread swine flu from person to person. It is feared that new strain may cause a human pandemic. The symptoms are usually similar to normal seasonal influenza but some people infected with swine virus have severe illness and even death may occur. The incidence of mortality is high in pregnant women, young children, elderly persons and individual suffering from chronic medical ailments as chronic lung disease, liver disease, heart disease and immuno suppression. Recently a vaccine has been launched ,which is being used in various countries. At present no vaccine has been marketed in India. There is lot of debate about the utility of anti swine flu vaccine. Only one dose of 1.0ml is given subcutaneously

Disease :

A combination of tetanus toxoid, reduced diphtheria toxoid and whole pertussis vaccine was used in past in place of tetanus, diphtheria and pertussis vaccines being used individually and separately. With the development of acellular pertussis vaccine, now a days combinations of tetanus toxoid diphtheria toxoid and acellular pertussis vaccine is in use. Adults who have not previously been immunized should receive a dose of Tdap followed by a dose Td 4 weeks later and a booster dose with Td 6-12 months after the second dose. Adults aged 19-64 years should receive a single dose Tdap in place of Td if they have received their last dose of Td 10 years earlier and have not received Tdap earlier. Parents and healthcare providers of less than 65 years, who are likely to come in contact with infants less than 12 months of age, should be given a single dose of Tdap even at an interval of 2 years from the previous dose of Td vaccination. Whenever possible, women should be given vaccine Tdap before becoming pregnant or immediately during post-partum if not vaccinated earlier.

Disease :

Tetanus is acquired through environmental exposure to the spores of Clostridium tetani, which are present in soil worldwide. The disease is caused by the action of a potent neurotoxin produced by the bacterium in dead tissue (e.g. dirty wounds). Clinical symptoms of tetanus are muscle spasms, initially of the muscles of mastication causing trismus or “lockjaw”, which results in a characteristic facial expression – risus sardonicus. Trismus can be followed by sustained spasm of the back muscles (opisthotonus) and by spasms of other muscles. Finally, mild external stimuli may trigger generalized, tetanic seizures, which contribute to the serious complications of tetanus (dysphagia, aspiration pneumonia) and lead to death unless intense supportive treatment is rapidly initiated.

Vaccine:

Tetanus vaccines stimulate production of a protective antitoxin. In general, adsorption on aluminum hydroxide or aluminum phosphate improves antigenicity. Tetanus toxoid is available as single toxoid (TT), combined with diphtheria toxoid (DT), or low dose dephtheria toxoid (Td), or combined with diphtheria and pertussis vaccine (whole pertussis – wP or acellular pertussis – aP). Vaccine combinations containing diphtheria toxoid (D or d) and tetanus toxoid, rather than tetanus toxoid alone, are being used now when immunization against tetanus is indicated. Primary immunization for children under 10 years consists of 3 doses of a combined preparation containing adsorbed tetanus vaccine, with an interval of 1 month between doses. The recommended schedule of tetanus vaccination not only gives protection against tetanus in childhood but also gives the basic immunity for subsequent booster doses. For primary immunization of adults and children over 10 years previously unimmunised against tetanus, 3 doses of adsorbed diphtheria [low dose] and tetanus vaccine are given with an interval of 1 months between doses. Following routine childhood vaccination, 2 booster doses of a preparation containing adsorbed tetanus vaccine are recommended, the first before school entry and the second before leaving school. Wounds are considered to be tetanus prone if they are sustained more than 6 hours before surgical treatment or at any interval after injury and are puncture type (particularly if contaminated with soil or manure) or show much devitalized tissue or are septic or are compound fractures or contain foreign bodies. All wounds should receive thorough cleansing. The type of tetanus prophylaxis that is required following injury depends on the nature of the lesion and the history of previous immunizations. However, no booster is needed if the last dose of tetanus vaccine was given less than 5 (for dirty wounds) to 10 years (for clean wounds) previously. Individuals whose primary immunization is incomplete or whose boosters are not up to date require a reinforcing dose of a tetanus containing vaccine (followed by further doses as required to complete the schedule); non-immunized individuals (or whose immunization status is not known or who have been fully immunized but are now immuno compromised) should be given a dose of the appropriate tetanus containing vaccine immediately followed by completion of the full course of the vaccine. For tetanus prone wounds, management is as for clean wounds with the addition of a dose of tetanus immunoglobulin given at a different site in fully immunized individuals the immunoglobulin is needed only if the risk of infection is especially very high. Systemic as well as local tetanus immunoglobulin is given in individuals with tetanus prone wounds where no immunization or incomplete immunization has taken place. Very rarely, tetanus has developed after abdominal surgery; patients awaiting elective surgery should be asked about tetanus immunization and immunized if necessary. Parenteral drug abuse is also associated with tetanus; those abusing drugs by injection should be vaccinated if unimmunised. Booster doses should be given if there is any doubt about the immunization status. All laboratory staff should be offered a primary course if unimmunised. All travellers should be up to date with the vaccine before departure.

Tick borne encephalitis is cause by TBE virus. It is usually a consequence of exposure to infected ticks, although unpasteurized cow’s, sheep’s and goat’s milk are recognized forms of transmission. The incubation period is 7-14 days for tick borne exposures but only 3-4 days for milk ingestion. The principal reservoirs for TBE virus are small rodents; humans are an accidental host.

Vaccine:

Tick-borne encephalitis vaccine is licensed for immunization of those in high-risk areas. Those working, walking or camping in warm forested areas of Central and Eastern Europe and Scandinavia, particularly from April to October when ticks are most prevalent, are at greatest risk of tick-borne encephalitis. Ideally, immunization should be completed at least one month before travel. Two vaccines are available in Europe, in adult and paediatric formulations. These are inactivated whole-cell vaccines containing a suspension of purified tick-borne encephalitis virus grown on chick embryo cells and inactivated with formaldehyde. Both provide safe and reliable protection. Immunity is induced against all variants of the tick-borne encephalitis virus including the European and Far Eastern subtypes. Two doses of 0.5 ml should be given i.m. 4–12 weeks apart. A third dose is given 9–12 months after the second dose and confers immunity for 3 years. Booster doses are required to maintain immunity and should be given every 3 years if the risk continues. Outside endemic countries, the vaccines are not indicated.

Tuberculosis, one of the oldest diseases known to affect humans, is a major cause of death worldwide. The disease, which is caused by the bacteria of mycobacterium tuberculosis complex, usually affects the lungs but other organs are involved in upto 1/3rd of cases. Transmission usually takes place through airborne spread of droplet nuclei produced by patients infected with pulmonary tuberculosis. Tuberculosis occurs disproportionately among disadvantaged populations such as malnourished, homeless, those living in over crowded and substandard housing. There is an increased occurrence of tuberculosis among HIV positive individuals.

Vaccine:

All versions of the BCG vaccine are based on live, attenuated mycobacterial strains descended from the original, attenuated bacillus Calmette-Guérin. The vaccine is administered intradermally and can be given simultaneously with other childhood vaccines. BCG vaccine is contraindicated for persons with severely impaired immunity, including individuals with HIV infection. BCG vaccine is of very limited use for travellers. In the first year of life it provides good protection against forms of TB associated with haematogenous spread (miliary TB and meningitis). In countries with high TB prevalence, infants are generally immunized with a single dose of BCG as soon after birth as possible. Children who are known to be HIV-infected, even if asymptomatic, should not be immunized with BCG vaccine but WHO has recommended that asymptomatic HIV infected chidren residing in endemic areas should receive BCG. Other protective benefits of the vaccine are uncertain. BCG should be considered for unimmunized infants travelling from an area of low incidence to one of high incidence. Many industrialized countries with a low incidence of TB have ceased giving BCG routinely to neonates. Booster doses of BCG are never recommended.

Disease :

Typhoid fever is systemic disease characterized by fever and abdominal pain and is caused by dissemination of S typhi or S para typhie. The infection is transmitted by consumption of contaminated food or drink. Incubation period is between 5-14 days. The infection localizes primarily in the lymphoid tissue of the small intestine but may disseminate to lungs, gall bladder, kidneys or CNS. The incubation period for S typhie averages 10-14 days. The most prominent symptom is prolong fever which ascends in a stepwise fashion. Other features include headache, chills, cough, sweating, myelgia, malaise, arthregia, anorexia, abdominal pain, nausea and vomiting. The rash (rose spots) commonly appears during the second week and found principally on the trunk. These rashes disappear within 3-4 days after the appearance.

Vaccine:

Typhoid immunization is advised for travellers to areas where sanitation standards may be poor, although it is not a substitute for scrupulous personal hygiene. Immunization is also advised for laboratory workers handling specimens from suspected cases. Capsular polysaccharide typhoid vaccine is usually given by intramuscular injection in a single dose and produces protection 7 days after the injection. Young children may respond sub optimally to the vaccine, but children aged between 1-2 years should be immunized if the risk of typhoid fever is considered high (immunization is not recommended for infants under 12 months). Booster doses are needed every 3 years on continued exposure. An oral typhoid vaccine is also available. The duration of protection following oral vaccine is not well defined and may vary with vaccine dose and possibly subsequent exposure to S-Typhi infection. It is a live attenuated vaccine contained in an enteric-coated capsule. It is taken by mouth as 3 doses of one capsule on alternate days, providing protection 7-10 days after the last dose. Protection may persist for up to 3 years in those constantly (or repeatedly) exposed to Salmonella typhi, but occasional travellers require further courses at intervals of 1 year. Oral typhoid vaccine is contra-indicated in individuals who are immunosuppressed (whether due to a disease or its treatment) and in acute gastro-intestinal illness. Oral typhoid vaccine is inactivated by concomitant administration of antibacterial or antimalarials. Administration of a dose of oral typhoid vaccine should be coordinated so that mefioquine is not taken for at least 12 hours before or after a dose; vaccination with oral typhoid vaccine should preferably be completed at least 3 days before the first dose of mefloquine or other antimalarials (except proguanil hydrochloride with atovaquone, which may be given concomitantly). These vaccines are not recommended for use in infant immunization programmes: There is insufficient information on their efficacy in children under 2 years of age.

Disease :

The causative pathogen is the varicella zoster virus (VZV). Varicella (chickenpox) is an acute, highly contagious disease with worldwide distribution. In temperate climates most cases occur before the age of 10 years. The epidemiology is less well understood in tropical areas, where a relatively large proportion of adults in some countries are seronegative. Transmission is via droplets, aerosol or direct contact, and patients are usually contagious from a few days before rash onset until the rash has crusted over. While mostly a mild disorder in childhood, varicella tends to be more severe in adults. It is characterized by an itchy, vesicular rash, usually starting on the scalp and face, and initially accompanied by fever and malaise. As the rash gradually spreads to the trunk and extremities, the first vesicles dry out. It normally takes about 7–10 days for all crusts to disappear. The disease may be fatal, especially in neonates and immunocompromised persons. Complications include VZV- induced pneumonitis or encephalitis and invasive group A streptococcal infections. Following infection, the virus remains latent in neural ganglia; upon subsequent reactivation, VZV may cause zoster (shingles), a disease affecting mainly immunocompromised persons and the elderly.

Vaccine:

Varicella-zoster vaccine Varicella-zoster vaccine (live) is licensed for immunisation against varicella in seronegative individuals. It is not recommended for routine use in children but can be given to seronegative healthy children over 1 year who come into close contact with individuals at high risk of severe varicella infections. Two types of vaccine are used for prevention of VZV infection. First a live attenuated varicella vaccine (oka) is recommended for all children of more than 1 year of age (upto 12 years of age) who did not have chicken pox or for adults known to be seronegative for VZV infection. Live attenuated vaccine is given as single dose in children, while 2 doses, 4–8 weeks apart, are recommended for adolescents and adults. Second inactivated virus vaccine which contains 18 times of the viral content of the Oka vaccine is being administered to immunocompromised persons with success. It is being recommended for individuals of more than 60 years of age. Live Varicella-zoster vaccine is contra-indicated in pregnancy (avoid pregnancy for 3 months after vaccination). It must not be given to individuals with primary or acquired immunodeficiency or to individuals receiving immunosuppressive therapy. Rarely, the varicella-zoster vaccine virus has been transmitted from the vaccinated individual to close contacts. Therefore, contact with the following should be avoided if a vaccine-related cutaneous rash develops within 4--6 weeks of the first or second dose: varicella-susceptible pregnant women; individuals at high risk of severe varicella, including those with immunodeficiency or those receiving immunosuppressive therapy. Vaccines for Travellers: Vaccines in this section need be offered only to travellers who are going to certain specific destinations. The decision to recommend a vaccine will depend on a travel risk assessment for the individual.

Disease :

Yellow fever is the virus infection which is transmitted by AEDES and Jungle mosquitoes. The mosquitoes transmit the infection by first biting an individual having the disease and then biting a susceptible individual after the virus has multiplied within the mosquito’s body. The incubation period in humans is 3-6 days. Adults and children are equally susceptible, though attack rates are highest among adult males because of their work habits. Between 5% and 50% of infection are asymptomatic.

Vaccine:

The 17D vaccine, which is based on a live, attenuated viral strain, is the only commercially available yellow fever vaccine. It is given as a single subcutaneous (or intramuscular) injection. Live yellow fever vaccine is indicated for those traveling or living in areas where infection is endemic and for laboratory staff who handle the virus or who handle clinical material from suspected cases. Infants under 6 months of age should not be vaccinated because there is a small risk of encephalitis; infants aged 6-9 months should be vaccinated only if the risk of yellow fever is high and unavoidable. The immunity which probably lasts for life is officially accepted for 10 years starting from 10 days after primary immunization and for a further 10 years immediately after revaccination. The vaccine should not be given to those with impaired immune responsiveness, or who have had an anaphylactic reaction to egg; it should not be given during pregnancy but if a significant risk of exposure cannot be avoided then vaccination should be delayed to the third trimester if possible (but the need for immunization usually outweighs risk to the fetus; however pregnant women should be advised not to travel to areas where exposure to yellow fever may occur).