Influenza Vaccine Less Effective in Seniors Taking Statins

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On Oct. 29, 2015, The Journal of Infectious Diseases published the results of two studies that indicate the influenza vaccine is less effective in seniors taking statins. According to CBS News, the studies were funded by the Switzerland-based pharmaceutical company, Novartis. The first study took place during the 2009-2010 and 2010-2011 flu seasons and included nearly 7,000 adults who were over 65 in the U.S., as well as three other countries. The second study analyzed approximately 140,000 people between 2002 and 2011.

Clinical Study at the Center for Global Health

The study data was compiled by researchers at the Center for Global Health at the Cincinnati Children’s Hospital in Ohio. They reviewed medical records of patients, 65 years and older, who had taken part in the clinical trial of a flu vaccine.

Information collected from tests taken during the trial was evaluated. The test results indicated that three weeks after immunization the antibodies levels were 38-67 percent lower in patients who use statins. There were two variables. First, the percentages depended on the type of flu strain. Second, natural statins appeared to have fewer adverse effects than synthetic. An example of a natural statin would be red yeast rice. Whereas, prescription medications such as Lipitor, Crestor, and Zocor are examples of synthetic statins.

Dr. Steven Black, the primary author of the first study, explained it is apparent that statins interfere with a person’s response to an influenza vaccine. Additionally, it also appears that statins result in a lower effectiveness of the medication.

The Emory Vaccine Center’s Study

The second flu shot effectiveness study was completed at the Emory University in Atlanta, Ga. Researchers analyzed the medical records of Kaiser Permanente health care plan patients. The study was done using data from flu vaccinations, statin prescriptions, and information from patient’s records, who suffered acute respiratory illnesses, which can be caused by influenza.

According to Associate Professor Dr. Saad Omer, “If you are on statins, the flu vaccine is slightly less effective.” WebMD notes the doctor added, “this might not be the complete story,” because statins have inflammation-fighting powers that could help the body fight off the flu-related infection.

Experts warned that more research is necessary to understand the impact of statin usage and antibody reduction thoroughly. Even though there is evidence that the influenza vaccine is less effective in seniors taking statins, it is important to continue taking the cholesterol-reducing medications prescribed by their physicians.

Immunization Information for Seniors

  • Medical News Today (MNT) reports that if the study results are confirmed, they could validate the need for high-dose flu vaccines. Additionally, there could be evidence supporting the use of vaccines containing adjuvants to aid in boosting the immune systems in older adults.
  • Currently, there is a high-dose immunization available for those over 65 in the U.S. However, the use of Novartis Pharmaceutical’s vaccine containing adjuvant is only licensed for use in Europe.
  • While there are higher dosage vaccines approved for seniors, as well as several standard dosages, the Centers for Disease Control and Preventation (CDC) and its Advisory Committee on Immunization Practices have not “expressed preference for any flu vaccine indicated for people 65 and older.”
  • According to the CDC, the Fluzone High-Dose vaccine clinical trials suggest a stronger immune response in seniors when compared to the standard dose of Fluzone. However, it is yet to be determined if this leads to greater protection against the disease. Further studies are needed.

General Influenza Immunization Information Influenza

  • The CDC reports that over 118 million doses of the flu vaccine for the 2015-2016 season have been distributed this year. They recommend everyone six months and older receive a yearly influenza immunization.
  • After vaccination, it takes two weeks for the antibodies to develop in one’s body and become protected from the flu virus. A person can still have flu-like symptoms, even after inoculation. The age and health status of an individual are factors that determine if a person will develop an influenza infection.
  • The annual vaccination rule is especially true for those over 65, since the human immune defense system weakens with age, thereby increasing the risk of severe illness from the flu.
  • According to MNT, the majority of flu cases are not serious, but some people can have severe complications.

Overall, the results of both studies found that the influenza vaccination is less effective in seniors taking statins. However, more research is necessary to validate the studies.

By Cathy Milne
Edited by Leigh Haugh

CBS News: Flu vaccine Might Be Less Effective in Statin Users
Medical News Today: Flu Vaccine Effectiveness Reduced by Use of Statins
WebMD: Statins May Dampen Flu Vaccine Powers
CDC: Influenza Information
Featured Image Courtesy of Army Medicine’s Flickr Page – Creative Commons License
Inset Image Courtesy of Frank Gruber’s Flickr Page – Creative Commons License