October 29, 2015

expert reaction to two new studies investigating statins and the immune response to flu vaccine in the elderly

Two studies have been published in the Journal of Infectious Diseases which report that statins (cholesterol-lowering drugs) have a negative impact on the effectiveness of flu vaccines in elderly patients.

Sotiris Antoniou, spokesperson on cardiovascular medicine for the Royal Pharmaceutical Society, and consultant pharmacist, said:

“Statins are known to have effects on the immune system and so a potential interaction with the flu jab is indeed possible.

“However, we must recognise that the findings of a reduced effect of the flu jab may be due to other things as the original study was not set out to assess the impact of statins on the effectiveness of vaccines.

“There’s good evidence to show taking statins protects your health.  Until more research is done to answer the question of a potential interaction between statins and the jab and the implications of the vaccine having a reduced effect, you should go on taking your statins as normal.  The protection they offer your cardiovascular system are significant, so don’t stop them without talking to a health professional.”

Prof. Peter Weissberg, Medical Director at the British Heart Foundation, said:

“These two studies suggest that some types of statins may reduce the effectiveness of standard influenza vaccination. However, as the researchers point out, their findings are far from conclusive and merely point to a possible issue that needs further research.

“No one who is planning to have a flu vaccination this winter should stop taking their statin on the basis of these studies. Indeed patients with heart disease are at greater risk of a heart attack if they catch flu and therefore need the protection of their statin. It is important that patients with heart disease should be vaccinated against flu and continue to take all of their medication.”

Prof. Sarah Gilbert, Professor of Vaccinology, University of Oxford, said:

“Statins are widely prescribed to older adults to reduce cholesterol levels, but are known to have a suppressive effect on the immune system. Older adults are more likely to develop severe disease with life-threatening complications if infected with influenza, and so annual influenza vaccination is recommended for everyone over the age of 65. Two new studies published this week looked at the immune response to influenza vaccination and the ability of the vaccine to prevent influenza disease in older adults who were taking statins, and found that both the immune response and the ability of the vaccine to prevent disease were reduced in those taking statins. We already know that the influenza vaccine is only moderately effective in older adults, so the new findings that taking statins may reduce vaccine effectiveness requires further investigation.

“The results are not simple to interpret as the people included in the study who were taking statins may have been in poorer general health than those who were not, which may partly explain the findings. However there is now sufficient evidence from these two large studies to prompt further investigation, and the consideration of routine use of improved influenza vaccines in older adults, especially those taking statins.

“There had been earlier studies which did not find that statins reduced the immune response to vaccination. However these small studies were carried out on younger people, who only took statins for a short period. This highlights the need to conduct clinical trials in older adults in order to provide that age group with the most effective vaccines.”

First study: ‘Influence of statins on influenza vaccine response in elderly individuals’ by Steven Black et al. published in the Journal of Infectious Diseases on Thursday 29 October 2015.

Second study: ‘Impact of statins on influenza vaccine effectiveness against medically attended acute respiratory illness’ by Saad B. Omer et al. published in the Journal of Infectious Diseases on Thursday 29 October 2015.

Declared interests

Sotiris Antoniou: “I have no interests to declare relating to this report.”

Prof. Sarah Gilbert: “I am employed by the University of Oxford and work on the development of improved influenza vaccines.”

None others received.