People aged 65 and older are a priority target group for flu vaccination because the risk of suffering serious complications from influenza rises with age.
Unfortunately, as the immune system ages, the response to vaccines can fall too. This may create a serious problem: it means one of the groups at highest risk of serious illness or death following flu infection benefits least from vaccination.
To be clear, flu vaccination is recommended by the WHO, national health authorities and professional medical societies especially for older people. If in doubt, ask your own doctor. While the effectiveness of the flu vaccine varies somewhat from year to year, it is always better to be vaccinated than to be unprotected.
Herd immunity
Experts have been exploring new ways to protect vulnerable older people from flu. In addition to encouraging everyone over 65 to be vaccinated annually, vaccinating other people in the community helps to reduce the risk of the disease spreading to those at risk.
In the UK, for example, a childhood flu vaccination programme is helping to curb the rate of flu infections in children but also protects their grandparents and other senior members of the community.
Now, a new study in Clinical Infectious Diseases, a scientific journal, shows that when younger adults – aged between 18 and 64 – are vaccinated, the risk to older people is reduced. This adds to the case of building herd immunity against flu outbreaks.
The US-based researchers behind the new study looked at data from more than 3 million people across eight flu seasons. They found that over 65s were 21% less likely to be diagnosed with flu-related illness if they lived in areas where more adults under 65 were immunised.
The study showed that if around one in three adults between the ages of 18 and 64 were vaccinated, they could spare some older people the pain, discomfort and cost of serious illness or hospitalisation.
“Our findings suggest that flu vaccination should be encouraged among low-risk adults not just for their own benefit, but also for the benefit of higher-risk adults in their community, such as the elderly,” said Dr Glen B. Taksler of the Cleveland Clinic who led the study.
Interestingly, the reduction in risk for flu-related illness that the researchers observed was more than twice as large for over 65s who were also vaccinated against flu themselves, compared to older adults who were not immunised. This suggests that communitywide vaccination may somehow boost the protection provided by individual vaccination, according to the authors.
Question: do younger adults have a social responsibility to have a flu vaccine?
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