Every year during flu season, seniors flood doctors’ offices to get immunized, despite mounting evidence that the vaccine is less effective than advertised. Now two new studies have found that, for the millions who take statins to lower their cholesterol, the vaccine may have even less impact on their ability to fend off the virus.
Reviewing data from a clinical trial involving nearly 7,000 people over age 65 during the flu seasons of 2009–2010 and 2010–2011, researchers at Cincinnati Children’s Hospital Medical Center found that those taking statins had a “significantly reduced immune response” to the influenza vaccine compared with those who were not taking the drugs.
“Apparently, statins interfere with the response to influenza vaccine and lower the immune response, and this would seem to also result in a lower effectiveness of influenza vaccines,” said lead study author Steven Black, MD.
Those findings were confirmed in a more focused study at Emory University, where researchers analyzed how statins affected the vaccine’s ability to prevent serious respiratory illness. The team, led by Saad Omer, MBBS, MPH, PhD, studied data from nine flu seasons between 2002 and 2011 involving almost 140,000 seniors served by a managed-care organization in Georgia.
The study showed that statin users were more susceptible to respiratory illness than nonusers after being vaccinated, Omer told The Journal of Infectious Diseases, which published the results of both studies. “What we found was a potential signal that the effectiveness of flu vaccine in older people may be compromised somewhat if they are on statins, compared to those who are not on statins,” he said.
About four in 10 Americans over 65 take statins to reduce their cholesterol, but the recent findings should not lead seniors — or their doctors — to abandon that treatment approach, according to Robert Atmar, MD, and Wendy Keitel, MD, of Baylor College of Medicine.
“Instead,” they wrote in a commentary that accompanied the studies’ findings, “the results of these studies should be viewed as hypothesis-generating and should prompt further investigations into whether statins reduce inactivated influenza vaccine immunogenicity and, if so, the mechanisms by which immune responses and associated vaccine effectiveness are adversely affected.”
To learn how to lower your cholesterol without statins, read “Cholesterol Reconsidered” in our June 2009 issue.