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For all the good they do (which is considerable), influenza vaccines are not perfect. They are drugs that can, and sometimes do, produce undesired side effects.
Most of the time, these adverse reactions are relatively minor; injection site soreness, mild fever, or a day’s malaise.
While it rarely happens, more serious side effects can occur.
Which is why the CDC and the FDA monitor adverse incident reports surrounding the receipt of vaccines via several methods, including the VAERS reporting system.
Recently the VAERS system has indicated a small – but higher than expected - number of febrile convulsions in children under the age of 2 years, who had recently received Sanofi’s Fluzone Vaccine.
According to a Reuters Report yesterday, 42 instances of febrile convulsions had been reported by mid-December, occurring shortly after receipt of the Fluzone vaccine. Of those 38 happened within 24 hours.
In all cases, these children recovered and apparently suffered no long-term effects.
Febrile convulsions are, of course, very common in children under the age of 2. In it’s Q&A on Febrile convulsions and vaccines, the CDC states (excerpts):
- Febrile seizures are not uncommon. About 2%-5% of young children will have at least one febrile seizure.
- Most children who have febrile seizures recover quickly and have no lasting effects. However, febrile seizures often result in a visit to an emergency room and can be very frightening for parents and caregivers.
While no direct link to the Fluzone vaccine has been established, investigators will look into these reports further.
In the meantime, the CDC continues to advise parents to get their children over the age of 6 months vaccinated against influenza.
You may recall that last year in Australia a temporary moratorium was put in place on giving CSL Limited’s 2010 flu shot to children under the age of 5 after an unusual number of febrile convulsions were observed (see Australia Investigating Adverse Vaccine Reactions).
As a result, CSL’s exported pediatric vaccine Afluria, was not recommended for use in young children this year in the United States (see FDA Approves 2010-2011 Flu Vaccines).
Although these reports will likely be used as fodder by anti-vaccination advocates, it is important to remember that – on average - scores of children die every year in this country due to flu-related illness.
Vaccination, while not 100% effective, remains their best protection against influenza.
Here is a link, and some excerpts from, yesterday’s FDA notice.
Fluzone Vaccine Safety
FDA and CDC Update on Fluzone Influenza Vaccine and VAERS Reports of Febrile Seizures in Children
January 20, 2011
The Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) routinely monitor the safety of all U.S. vaccines by using several vaccine safety surveillance systems, including the Vaccine Adverse Event Reporting System (VAERS). VAERS collects and analyzes information from reported adverse events (health problems or possible side effects) that occur after vaccination.
FDA and CDC have recently detected an increase in the number of reports to VAERS of febrile seizures following vaccination with Fluzone (trivalent inactivated influenza vaccine or TIV, manufactured by Sanofi Pasteur, Inc.). Fluzone is the only influenza vaccine recommended for use for the 2010-2011 flu season in infants and children 6-23 months of age. These reported febrile seizures have primarily been seen in children younger than 2 years of age. Data from VAERS are preliminary and serve as a sign or indication that further investigation is warranted. Further investigations are under way to assess whether there could be an association between influenza vaccination and febrile seizures, or if other factors could be involved. FDA and CDC have seen no increase in VAERS reports of febrile seizures in people older than 2 years of age following vaccination with TIV, and no increase after live attenuated influenza vaccine (FluMist, the nasal spray vaccine). In the cases reported, all children recovered and no lasting effects have been seen.
Recommendations for the use of flu vaccine in children have not changed.
FDA and CDC will continue to conduct studies and provide additional information to the public and health care providers as it becomes available.
