Patients, particularly elderly people taking statin cholesterol drugs could be lowering the effectivity of their flu vaccines. Two studies linked statin medication to reduced flu vaccine protection and increased risk in developing respiratory illnesses.
In the first study, researchers from Cincinnati Children's Global Health Center (CCGHC) worked with scientists from Novartis Vaccines to analyze the data from a clinical trial of trivalent influenza vaccine (TIV). The team looked into the flu vaccine's effectivity on 7,000 participants aged 65 years old and above during flu seasons from 2009 to 2011 in the United States, the Philippines, Colombia and Panama.
Antibody levels were reviewed three weeks after the TIV was administered. Researchers found that there is a substantial decrease in the immune response to TIV in people who use statin-based medications. Patients who don't use statins created 38 percent to 67 percent antibodies to fight the influenza virus compared to patients who use the drug. Moreover, there is a huge difference in the reduced effects between patients who take synthetic and natural statins.
Natural statins come from fungal compounds. Drugs with natural statins include lovastatin, simvastatin and pravastatin. Synthetic statin drugs include fluvastatin, atorvastatin and cerivastatin.
"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 author Dr. Steven Black, faculty member at CCGHC.
Further studies is needed to confirm the connection between dampened immune response among statins users. Once confirmed, elderly patients can opt to take a higher dose of vaccine or adjuvant-containing vaccines to boost their immune response. There is currently no approved flu vaccine with adjuvants, however, these are being employed in other countries for years.
The U.S. Food and Drug Administration panel suggested in September the approval of Novartis' adjuvanted flu vaccine specifically made for elder people aged 65 years old and above. It would be the U.S.' first adjuvant-containing flu vaccine once given approval.
The secondary study involved a research from a team in Emory University who looked into data covering seven flu seasons from 2002 to 2011. The study involved almost 140,000 people aged 45 years old and above who get health care from Kaiser Permanente in Georgia where the researchers examined their statin medication, flu vaccination status and acute respiratory illnesses.
The team found indications that the effectiveness of flu vaccines can be dampened in patients who take statins (12.6 percent) compared to patients who don't (26.2 percent), explained lead author Saad Omer, MBBS, PhD, MPH.
Adjustments were made to factor in external influences and the team found that the vaccine's effectiveness in fighting against respiratory illnesses were lower in patients taking statin medication, particularly during flu season.
The immune response study entitled "Influence of Statins on Influenza Vaccine Response in Elderly Individuals" and the respiratory illness study entitled "Impact of Statins on Influenza Vaccine Effectiveness Against Medically Attended Acute Respiratory Illness" were published in The Journal of Infectious Diseases on October 28, 2015.
Photo: Daniel Paquet | Flickr
