High Rates of Adverse Events Linked with 2009 H1N1 Pandemic Vaccine

Nearly 10 years ago, in 2009, the influenza A (H1N1)pdm09 virus spread throughout the world, marking the most recent influenza pandemic since 1968.

The virus was first detected in the United States, where, according to an estimate by the US Centers for Disease Control and Prevention, it ultimately led to 60.8 million cases of influenza and 12,469 deaths.

After the first cases were detected in April 2009, health officials around the world began initiating pandemic responses and rolling out new vaccinations, designed especially for pandemic response.

One such vaccination administered across Europe—Pandemrix—has now been implicated in a new report by Peter Doshi, associate editor of The BMJ, who suggests that the vaccine had serious safety issues that led to an influx of adverse events and that these safety concerns were not communicated to the public.

According to the report, Pandemrix, a split virion, inactivated, adjuvanted vaccine, was associated with an increased rate of adverse events in comparison with 2 other vaccines produced by its manufacturer, GlaxoSmithKline.

During the pandemic, an estimated 30 million Europeans were administered the vaccine, after which, more than 1300 individuals who received the vaccine reported onset narcolepsy, according to The BMJ report. Speaking on these reports, GSK told The BMJ that “further research is needed to confirm what role Pandemrix may have played in the development of narcolepsy among those affected.”

Since then, new information has emerged from documents made available in a lawsuit against health officials in Ireland and GSK. The documents, obtained by a medical epidemiologist who served as a witness in the lawsuit, revealed the adverse events associated with all 3 GSK pandemic vaccines. The odds ratio was 5.39% [95% confidence interval 3.70 to 7.85] for deaths (Pandemrix vs the other vaccines).

According to the report of adverse events, dated December 2, 2009, there were a reported 3807 adverse events related to Pandemrix, 1138 of which were serious, and 47 of which were fatal. Adverse events of special interest detailed in the report included 141 cases of anaphylaxis, 12 cases of facial palsy, and 51 cases of convulsions, among others.

These reported adverse events are significantly higher than the other GSK vaccinations, according to Doshi. Pandemrix recipients showed 4 times the rate of facial palsy, 8 times the rate of serious adverse events, 9 times the rate of convulsions, and most critically, 5 times more reported adverse events than Arepanrix and the other unadjuvanted vaccine produced by GSK.

“But neither GSK nor the health authorities seem to have made the information public—nor is it clear that the disparity was investigated,” wrote Doshi in The BMJ piece.

The most recent report, which is from March 31, 2010, includes 5069 serious adverse events tied to 73 million vaccinations of Pandemrix, 7 times the rate for Arepanrix and the unadjuvanted vaccine combined.

The United Kingdom Department of Health declined to comment to The BMJ regarding why Pandemrix was selected instead of another pandemic vaccination such as Celvapan. Additionally, GSK failed to provide a copy of safety reviews of the vaccines requested by The BMJ.

Pandemrix was removed from the market after the pandemic, but the number of reported adverse events indicate a need for a stronger screening process for pandemic vaccinations in the future, according to Doshi.

Furthermore, he asserts that the key takeaway from this is that it raises an important question: when do health officials have a duty to warn the public of potential harms that have been detected through pharmacovigilance? How much does the public have the right to know?