Two articles in the Journal of Infectious Diseases suggest that statin-type cholesterol-lowering drugs may impair the effectiveness of the influenza vaccine.
Impact of Statins on Influenza Vaccine Effectiveness:
In one study, researchers analyzed health records stretching back over nine years. They found the flu vaccine appeared to be less effective in people taking statins compared to those not on such cholesterol-lowering drugs. The investigators noted:
“Our findings suggest that the antiinflammatory properties underlying the clinical benefits of statin therapy might also attenuate the immune response to influenza vaccine.”
Journal of Infectious Diseases, online Oct. 28, 2015
Influence of Statins on Influenza Vaccine Response in Elderly Individuals:
In the other study, vaccine scientists looked specifically at how well influenza vaccines protected older adults. The elderly, particularly those with chronic conditions such as heart or lung disease, are most susceptible to serious complications of the flu. They are also quite likely to be taking cholesterol-lowering statins to prevent heart attacks.
Data from a large study of flu vaccine effectiveness were retrospectively analyzed to see if there were differences in the reaction to the flu vaccine between those taking statins and those not on such drugs. The measure of effectiveness was a blood test to determine immune system reaction (hemagglutination-inhibiting geometric mean titers to three strains of influenza virus).
In this group of more than 5,000 participants, those taking statins had weaker immune responses to the flu shot, by 38 to 67 percent.
The investigators observed:
“While the immunosuppressive effects of statins may be desirable in the acute disease state, the same effect could be deleterious if it impacts vaccine response. We have shown that long-term statin therapy is associated with an apparent reduced response to influenza vaccine in elderly individuals. This observed negative effect should be taken into account when evaluating the immunogenicity of influenza vaccines in elderly individuals in the future.”
Journal of Infectious Diseases, online Oct. 28, 2015
The Bottom Line:
In recent years, the flu vaccine hasn’t been terribly effective. Last year, for example, the CDC reports that overall effectiveness was about 19 percent. Lowering that effectiveness further by taking a statin appears to be counterproductive.
Of course, these studies are both preliminary. Before doctors can draw definite conclusions about this possible interaction, they will want to see the results of a study designed to look specifically at this question.
To learn more about adverse reactions to this year’s flu shot, you may want to read this article.
