Statin use weakens flu vaccine potency: study

Two recent studies published in the Journal of Infectious Diseases suggest that people taking statins to lower their cholesterol may not reap the full benefits of flu vaccines, Reuters reported.

"We felt the studies are important to bring this issue into the open so that the results can be verified by others and, most importantly, strategies can be developed to optimally protect this high risk group against influenza," said Dr. Steven Black from the Center for Global Health at Cincinnati Children's Hospital in Ohio.

Pausing statin use for a period of time prior to vaccination could possibly enhance the effectiveness of flu shots but it might increase the likelihood of heart disease and stroke. Thus, doctors advise the public to not favor one medication over the other. Older patients in particular, who are more likely succumb from both serious flu complications and heart attacks, should continue their prescribed regimen of medications and vaccinations.  

"Statins shouldn't be stopped because they already have been shown to lead to significant benefits such as decreased mortality due to cardiovascular events," said Dr. Robert Atmar, infectious disease researcher at Baylor College of Medicine and Ben Taub General Hospital in Houston. "Patients should also continue to get vaccinated against influenza because it is still the best way to prevent getting sick."

Both studies looked into the effect of flu vaccines on people who were or were not using statins.

The first study analyzed how well participants responded to different versions of the flu vaccine during the 2009-2010 and 2010-2011 flu seasons. It had more than 5,000 people over 65 from the U.S., Colombia, Panama and the Philippines. The study found that people who didn't take statins produced 38 to 67 percent more antibodies against the influenza virus than people who used the cholesterol medication approximately three weeks after the vaccination.

The second study, which examined rates of respiratory infections linked to influenza from 2002 to 2011 among people 45 and older, found that the flu vaccine was 26.2 percent effective in preventing infections in people not taking statins, but just 12.6 percent effective among those under statins.

However, it should be noted that results of the studies are not conclusive and are still under debate.

Since statin use was not randomly assigned in the studies, Dr. Jacob Udell from the University of Toronto and Dr. Orly Vardeny of the University of Wisconsin in Madison believe there might be other factors reducing the effectiveness of flu vaccines in statin-taking patients such as diabetes, obesity, and cardiovascular disease, among others, MedPage Today shared.