Once again, school has begun and our thoughts turn to one thing…the flu. Every year, the world is treated to this wintertime malady and health policy officials along with pediatricians urge parents to protect their children through vaccination. This annual ritual raises a lot of questions. The Academy of Pediatrics released its flu vaccination recommendations online today for this year’s flu season.
Here are some commonly asked questions about the upcoming flu season and vaccination:
Most vaccines are given at infrequent intervals. Why does my child have to receive a flu vaccine every year?
Good question. Through vaccination or actual infection, the U.S. population rapidly develops immunity to influenza virus strains that circulate through out the country each year (so-called “seasonal influenza”).
Humans are accidental hosts when it comes to infection with influenza virus. The natural creatures infected with this virus are waterfowl, notably ducks. The avian version of the virus (“bird flu”) is then spread to other fowl including domesticated chickens. In southeast Asia, chicken farmers live in close proximity to their birds and thus often serve as the bellweather for infections with new strains. Initially, only spread from birds to humans is seen. This method of infection is not very effective and does not support rapid spread throughout the world. Over time, some strains develop the capacity to be spread from human-to-human. Once this occurs, the potential exists for epidemic spread of a particular viral strain.
The World Health Organization (WHO) maintains surveillance outposts throughout this region and looks for new strains of flu that come from birds and begin to infect farmers. Flu strains that develop the ability to spread from human to human are identified as the next possible epidemic strain. Using this information, the Centers for Disease Control and Prevention (CDC) identifies the strains most likely to affect the U.S. and helps direct the manufacture of an appropriate vaccine.
So we only see one strain each year?
Usually not. The many different strains of influenza virus fall into two 2 main categories: type A and type B. In most years in the U.S., the number of type A infections far exceeds the number of type B infections. Often, more than one strain of type A influenza circulates in the population at one time. In general, the type A infections are more severe than the type B.
So what is in the vaccine and how does it work?
The strains selected for each annual vaccine are based on a “best guess” as to the strains that will prevail in the community each flu season. The traditional influenza vaccine contains killed influenza virus from 2 A strains and 1 B strain, thus the name inactivated trivalent vaccine.
For the first time, an inactivated quadrivalent vaccine (2 A strains and 2 B strains) is available this year. While testing suggests that the quadrivalent vaccine will provide adequate protection, there is no comparative data on protection with the traditional trivalent vaccine. As such, the American Academy of Pediatrics has approved both vaccines for your child, but does not prefer one over the other. Both vaccines are administered by injection.
For individuals without respiratory disease, who do not work in the healthcare field and who are “needle averse”, a preparation of live virus can be given as a nasal spray (“Flumist”). Flumist provides protection against the same flu strains as the inactivated trivalent vaccine, but in head-to-head trials is less effective.
Who should be vaccinated?
The American Academy of Pediatrics recommends that all children over 6 months of age receive the vaccine. Children with underlying neurologic, heart or lung disease are at greatest risk for complications from the flu so a special effort should be made to ensure that these children are protected.
How can I protect my children from the flu?
Vaccination is the first line of protection against influenza virus infection. Good hand washing is the second line. If your child develops the symptoms of flu - which can include fever, cough runny nose and body aches - this winter, fluids and temperature control with acetaminophen or ibuprofen is recommended. Specific treatment with antiviral therapy (oseltamivir; Tamiflu) is available from your child’s healthcare provider for selected cases.
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