Vaccines for Special Groups

Vaccines for special groups include meningococcal, typhoid and rabies.

The meningococcal disease is caused by Neisseria meningitidis, or meningococcus which is a gram-negative, biscuit-shaped diplococcus bacteria found only in man. Transmission is from person to person through respiratory droplets. It is not as contagious as the common cold but is transmitted through saliva, and occasionally, prolonged contact with an infected person. The incubation period is from 1 to 10 days. The clinical manifestations include upper respiratory infection with or without bacteremia; bacteremia without sepsis; meningococcemic sepsis without meningitis; meningitis with or without sepsis, meningoencephalitis and focal organ infections. This type of meningitis is the only form of bacterial meningitis known to cause epidemics. It is a serious condition. The more severe disease called meningococcemia is a widespread blood infection with a high rate of mortality. A patient afflicted with this disease can deteriorate within hours. Although a small number of patients die, those who survive incur long term sequelae like deafness and brain damage.

Typhoid or typhoid fever is caused by Salmonella typhi. It is acquired through ingestion of food or water contaminated by fecal material from an infected person. It is characterized by a sustained high fever, profuse sweating, and diarrhea. Occasionally, a rash with flat rose-colored spots may appear. If untreated, typhoid fever can lead to serious complications like intestinal bleeding and perforation, encephalitis, and abscesses and inflammation in other organs including the gallbladder, bones and the heart. Sanitation and good hygiene are critical preventive measures for typhoid.

Rabies is a highly fatal viral encephalomyelitis which is transmitted to man by the bite of a rabid animal. The rabies virus is a bullet-shaped rhabdovirus of the Lyssa group. It can be transmitted in either 2 ways: (1) bite exposure(injection of infectious saliva into abreak in the skin caused by animal's teeth) or (2) non-bite exposure by licking of mucous membranes or scratches, open/healing wounds,abrasions; aerosol; or human to human. The incubation period in man varies from as short as 4 days to as long as 19 years, but is usually between 20-90 days. Ninety five percent of cases develop symptoms within a year from the time of the bite. It tends to be shorter in multiple severe bites or bites on the head and neck areas. The clinical manifestations may range from a prodromal phase characterized by nonspecific constitutional symptoms such as fever, malaise, and body weakness followed by pain or paresthesia at the site of the bite then enters into an acute neurological phase with the characteristic feature of violent and painful spasm of the pharyngeal and laryngeal muscles and eventually death due to a respiratory paralysis.

With the existence of the above disease entities, the use of vaccines for each has been an option in certain areas or conditions.

The meningococcal vaccine is not recommended for routine use. It is recommended only in areas where there is an outbreak as declared by health authorities and for children and adolescents known to be at risk for the disease.

The typhoid vaccine is an active immunization against typhoid fever for adults and children older than 2 years of age. A single dose is recommended for both children and adults. Subjects who remain at risk of typhoid fever should be revaccinated using a single dose of vaccine every 3 - 5 years. This vaccine is also recommended for travelers to areas with a risk of exposure to salmonella typhi or persons infected with Salmonella typhi. There are two vaccines for typhoid - an oral live attenuated and an injectible.

Based on the Anti-rabies Act 2007, pre-exposure prophylaxis for children aged 5 years and above is recommended where there is a high incidence of rabies (>2.5 human rabies/million population). The regions with a high incidence of rabies reported in 2006 are Regions 1,2,3,5,7,8,12 and CAR. Booster is not mandatory but may be given every 3 years depending on continuing risk of exposure. Any exposure regardless of severity after completion of the Primary series should be given rabies vaccines as follows: interval from last dose of 0-6 months needs one booster dose, >6 months - 3 years, needs 2 booster doses(given on days 0, 3) and > 3 years require a full dose of vaccine (days 0,3,7,14,28) without Rabies immunoglobulin.

Childhood and Adolescent Immunization Schedules Approved for 2010

by Laurie Barclay, MD

The 2010 recommended childhood and adolescent immunization schedules have been approved by the American Academy of Pediatrics (AAP), the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention, and the American Academy of Family Physicians, according to a report posted online January 4 and to be published in the January 2010 issue of Pediatrics.
There are 3 revised schedules describing current guidelines for use of US Food and Drug Administration (FDA)–licensed vaccines: one for children from birth through age 6 years, one for children and adolescents aged 7 through 18 years, and a catch-up immunization schedule for children and adolescents who start late or fall behind with scheduled vaccinations.
Noteworthy changes in the 2010 schedule are a new recommendation for influenza A (H1N1) 2009 monovalent vaccine, a recommendation to revaccinate children who remain at increased risk for meningococcal disease with meningococcal conjugate vaccine (MCV4), recommendations on combination vaccines, and recommendations for the recently licensed bivalent human papillomavirus (HPV) vaccine in girls and the quadrivalent HPV vaccine in boys.
Specific changes from last year's recommendations for vaccination with FDA-approved vaccines include the following:
• A footnote refers to ACIP recommendations regarding use of influenza A (H1N1) 2009 monovalent vaccine.
• Only children 6 months or older should receive trivalent inactivated influenza vaccine (TIV), and only those 2 years or older should receive the live attenuated influenza vaccine (LAIV). Healthy children aged 2 to 6 years may receive either TIV or LAIV. However, children aged 2 to 4 years who have a history of wheezing in the preceding 12 months should not receive LAIV.
• The dose of TIV is 0.25 mL for children aged 6 to 35 months and 0.5 mL for those at least 3 years old. For children younger than 9 years given the influenza vaccine for the first time, 2 doses should be given 4 weeks apart. Children who received a single dose of influenza vaccine the previous season should be given 2 doses, separated by 4 weeks or more.
• Children who remain at increased risk for meningococcal disease because of persistent complement deficiency, asplenia, or other conditions should be revaccinated with MCV4. Children who received the initial MCV4 dose at ages 2 through 6 years should receive a dose of MCV4 after 3 years. If the first dose was given at age 7 years or older, children should be revaccinated after 5 years. These children should then be revaccinated with MCV4 every 5 years.
• Children not previously vaccinated with MCV4 should be given this vaccine at age 11 or 12 years or between ages 13 and 18 years. College freshmen living in a dormitory who have not previously received MCV4 should be given this vaccine.
• Combination vaccines are usually preferred to separate injections of the equivalent component vaccines. Updated recommendations regarding the inactivated poliovirus vaccine series are that the final dose should be given on or after the fourth birthday and at least 6 months after the previous dose. Children receiving 4 doses before age 4 years should receive an additional (fifth) dose at ages 4 through 6 years.
• Updated recommendations describe use of the recently licensed bivalent HPV vaccine in girls and the quadrivalent HPV vaccine in boys. Girls not previously vaccinated against HPV should receive the bivalent HPV series at ages 13 through 18 years. For catch-up, the second and third HPV dose should be given at 1 to 2 months and at 6 months after the first dose. The minimal interval for vaccination is 4 weeks between the first and second doses, 12 weeks between the second and third doses, and 24 weeks or more between the first dose and third dose.