A CBS News report indicates that two new studies showed that statins, drugs intended to lower cholesterol, might have an adverse effect on how well the flu vaccine works in older adults. The two studies, published in The Journal of Infectious Diseases, found that people taking statins had a notably reduced immune response to influenza vaccination compared to those not taking statins, which may affect future flu shot recommendations and/or statin use around the time of vaccination, according to experts.
The first study, which included almost 7,000 adults over the age of 65 in four countries, analyzed data on immune responses from an earlier flu vaccine clinical trial conducted during the 2009-2010 and 2010-2011 flu seasons. The researchers also looked at the possible effect of statin use on patients’ initial immune responses after getting a flu shot. After measuring the level of antibodies to the flu vaccine strains in patients’ blood after 3 weeks after receiving the shot, the research team concluded that statin users had a considerably reduced immune response to the vaccine compared to those not taking the drug.
The CBS News report notes that the effect was stronger in people taking synthetic statins as opposed to naturally derived varieties of the drug. Steven Black, MD, lead author of the immune response study, explains, “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.”
The second study from Emory University researchers examined the possible impact of statin use on the effectiveness of the flu vaccine in preventing severe respiratory illnesses. The research team analyzed data on close to 140,000 people spanning nine flu seasons from 2002 to 2011 that included information about statin prescriptions, flu vaccination, and cases of acute respiratory illness. After adjusting for other factors, the results of the analysis showed that vaccine effectiveness for preventing serious respiratory illness was lower among patients taking statins compared to those who were not.
The CBS News report notes that if confirmed, the researchers suggest that the findings could change recommendations for flu immunization in seniors, with preference for a high-dose flu vaccine to counteract the apparent effect of statins.
In a commentary, Robert L. Atmar, MD, and Wendy A. Keitel, MD, write, “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.”
Source: CBS News