Results are in from studies in the U.S., China, and Hungary.
An estimated 100 million doses of 2009 pandemic influenza A/H1N1 flu vaccines have been administered worldwide since September 2009. Three new reports, containing data previously available only to regulators, provide important information on the safety and efficacy of these vaccines. All vaccines used in these studies were inactivated injected vaccines, produced from a single H1N1 strain recommended by the World Health Organization.
In a randomized U.S. study, 1300 healthy people received one of three formulations of H1N1 vaccine or placebo. At baseline, 20% to 30% of adults and relatively few children had protective levels of H1N1 antibody; 21 days after vaccination, seroprotection rates were 92% to 100% in adults and 45% to 69% in children…