Women are more likely than men to experience reactions such as fever, headache, and sore arm after receiving the flu vaccine.
Side effects after the flu vaccine are more common in women, whose immune system may react more strongly.
The researchers analyzed data from more than 34,000 people who participated in 18 scientific studies looking at reactions to flu vaccines.
Among people over 65, who make up the largest group to receive the flu vaccine in the United Kingdom, women were 43 percent more likely than men to have a problem in the arm they received. injected, such as pain or swelling.
In this age group, women were also 27 percent more likely to have a “systemic reaction” such as fever, muscle pain or headache, which were individually more common in women than men.
The researchers analyzed data from more than 34,000 people who participated in 18 scientific studies looking at reactions to flu vaccines. Among people over 65, who make up the largest group to receive the flu vaccine in the United Kingdom, women were 43 percent more likely than men to have a problem in the arm they received. injected, such as pain or swelling.
In a bid to “get back to normal,” invitations will not be distributed to millions of people ages 50 to 64 who were eligible during the pandemic.
Women under 65 were also more likely than men to experience side effects from the flu vaccine.
Younger people, such as pregnant women and people with certain health conditions, are offered the vaccine on the NHS each winter.
Dr Marilou Kiely, who led the study from the University of Montreal, said: “We found that women were more likely than men to have reactions to the flu vaccine, regardless of their age or the type of flu vaccine. what did you recieve”.
“However, the likelihood of these flu vaccine reactions decreases as people age, for both women and men.
“Women should be aware that these reactions after vaccination are usually mild and improve on their own, as well as the potential benefits of the flu vaccine, which is most important for vulnerable people, such as those who are older or They already have certain health conditions.’
The study, published in the Journal of Epidemiology & Community Health, found that pain was the most common problem in the arm of people who received the flu vaccine.
Muscle pain and headaches were the most common reactions that affected the entire body.
The greater likelihood of this type of whole-body reaction in women would not affect many people: only 74 more women than men out of every 1,000 people vaccinated, the researchers estimate.
But the results suggest that women may also be more likely to have reactions that impact their lives.
Women over 65 were 51 percent more likely than men to have a more serious problem with the injected arm that, for example, made it temporarily difficult to perform daily activities such as housework.
They were 48 percent more likely to have a more serious reaction affecting the entire body, such as muscle aches and fever, which made it difficult to perform daily activities.
However, the difference between women and men in severe whole-body reactions was smaller in those over 65 than the difference between younger women and men.
Older women may have immune systems that react less to the flu vaccine than those of younger women.
In fact, older people in general tend to react less strongly to vaccines.
Analysis of studies conducted between 2010 and 2018, which looked at reactions within seven days of a flu shot, found that women were more likely than men to report reactions to flu vaccines, regardless of whether They had received the trivalent or quadrivalent vaccine, which protects against three or four strains of flu.
The study authors note that women are generally more likely to report and seek help for health problems, based on previous evidence, which may also make it appear that their risk of flu vaccine reactions is higher, compared to men. the men.
The quality of evidence in the studies reviewed was also moderate at best, meaning more research is needed.
More than 2.8 million people in England have received the flu vaccine since the start of the autumn booster campaign on September 11, according to figures from NHS England.