The National Vaccine Advisory Committee has endorsed a working group report concluding that no safety signals have been identified so far with the 2009 pandemic influenza A(H1N1) vaccine.
In a public teleconference, working group chair Dr. Marie McCormick said the group reviewed data for a total of 74 million doses of inactivated (injected) vaccine and 19 million doses of live attenuated (intranasal) H1N1 vaccine distributed as of around Christmas. They concluded that the data do not suggest a safety signal between the outcomes examined and the vaccine, defining “signal” as an outcome occurring more than anticipated by chance alone.
No serious increases in adverse events have been seen to date in any of the pandemic H1N1 vaccine clinical trials, and a comparison of serious events reported to the Vaccine Adverse Events Reporting System have shown similar levels between the H1N1vaccine and the seasonal influenza vaccine, as well as other vaccines. In addition, active surveillance systems that are using rapid-cycle analysis of prespecified outcomes have also been within expected values, said Dr. McCormick, the Sumner and Esther Feldberg professor of Maternal and Child Health at Harvard University, Boston.
However, she cautioned, the size of the population captured under active surveillance is still somewhat limited. A new federal project called Post-Licensure Rapid Immunization Safety Monitoring (PRISM), designed to monitor H1N1 vaccine safety in real-time using data from large health plans covering approximately 10% of the U.S. population, was getting underway at the time of the teleconference.
“As more data are available through active surveillance, conclusions will be based on a larger accumulation of data. Larger samples may be needed to detect rare adverse events,” she said.
The NVAC members voted to endorse the report during the teleconference. It was then sent to the U.S. assistant secretary for health for review and formal implementation.