New evidence shows immunization against "swine flu" in 1976 might provide individuals with some protection against the 2009 pandemic H1N1 influenza virus, according to new research from St. Jude investigators.
Researchers found that individuals who reported receiving the 1976 vaccine mounted an enhanced immune response against both the 2009 pandemic H1N1 virus and a different H1N1 flu strain that circulated during the 2008-09 flu season. The work appears in the April 23 online issue of the journal Clinical Infectious Diseases.
"Our research shows that while immunity among those vaccinated in 1976 has waned somewhat, they mounted a much stronger immune response against the current pandemic H1N1 strain than others who did not receive the 1976 vaccine," said Jonathan A. McCullers, MD, an associate member of the St. Jude Infectious Diseases Department and the study's lead author.
McCullers said it is unclear if the response was enough to protect against the 2009 H1N1 virus, but the study points to a lingering benefit. The findings also raise hope that those vaccinated against the 2009 H1N1 pandemic strain might also enjoy a similar long-term advantage.
The study is the first to focus on whether those vaccinated against the 1976 H1N1 strain made antibodies against the 2009 pandemic flu, including antibodies that could block the virus from infecting cells. This research follows an earlier study from the federal Centers for Disease Control and Prevention that reported blood taken from volunteers shortly after they were vaccinated in 1976 and stored for decades also showed a strong immune response to the 2009 pandemic virus. Investigators noted the results might not reflect the immune response those same volunteers would mount today.
The latest effort involved 116 St. Jude employees and spouses age 55 and older. The group included 46 vaccinated in 1976 against the H1N1 flu virus, known as A/New Jersey/76, which sickened more than 200 military recruits in New Jersey. That outbreak triggered fears of a flu pandemic and led to a massive government effort to quickly produce and distribute a vaccine.
