Study Finds H1N1 Vaccine Safety Similar to That of Seasonal Vaccines

In a couple of weeks, the Centers for Disease Control and Prevention will begin publishing new data on the 2010-11 flu season. And as people consider getting vaccinated this year, they may hear that there were more "adverse effects" from the H1N1 vaccine than from the regular flu shot last year.

That is true, but it is not the whole story -- not by a long shot. In fact, there was not a single death in last year's flu season that was confirmed as linked to the H1N1 vaccine. But hundreds of children died in connection with the H1N1 virus.

The Center for Infectious Disease Research & Policy reported about analysis by federal scientists that found that last season, the H1N1 vaccine's safety profile was similar to that of seasonal vaccines. While it is true there were more reports of adverse effects from the H1N1 vaccine last year compared to the regular flu vaccine, the rate of AEs as they are called in the health world was in line with overall seasonal numbers in the previous five-year period.

The researchers found that "serious adverse events (AEs) -- particularly Guillain-Barre syndrome (GBS), anaphylaxis, and death -- were rare, at less than two of each per-million people vaccinated, according to their early-release report ..."

The study said:

"Using data from the CDC's National 2009 H1N1 Flu Survey, the authors estimated that 82.4 million doses of H1N1 vaccines were administered in the 4-month study period. That included 64.6 million doses of inactivated vaccine and 17.5 million doses of live attenuated (intranasal) vaccine.

"The group also estimated that 125.5 million doses of seasonal flu vaccines were administered from August 2009 through January 2010, including 117.6 million doses of inactivated vaccine and 7.9 million doses of live vaccine.

"A total of 10,085 AE reports were submitted in connection with the H1N1 vaccine, of which 726 (7.2%) were classified as serious. For the seasonal vaccine, there were 6,469 reports, 540 (8.3%) of which were listed as serious.

"The total rates of AEs within the four different age-groups examined were 2 to 3 times higher for the H1N1 vaccine than for the seasonal vaccine, signaling significant differences, the report says.

"The rate of serious events reported for the pandemic vaccine was 8.8 per million doses, which was significantly higher than the 4.1 per million doses reported for the seasonal vaccine (P<.01). Serious events were defined as death, hospitalization, life-threatening illness, persistent or significant disability, or congenital anomaly."

In short, the study found that while there were 48 deaths related to the H1N1 vaccine, they were almost all linked to underlying medical conditions. It went on to say that there are no provable patterns showing that the H1N1 vaccine caused anyone to die.

On the other hand, the H1N1 flu was linked to at least 285 pediatric deaths. (A more comprehensive look at the statistics for the 2009-10 influenza season is here.)

The CDC said laboratories confirmed that influenza caused 41,821 hospitalizations and 2,117 deaths in the 2009-10 season.

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    Al Tompkins

    Al Tompkins is The Poynter Institute’s senior faculty for broadcasting and online. He has taught thousands of journalists, journalism students and educators in newsrooms around the world.


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