Women are more than twice as likely as men to report local adverse events (AEs) following influenza or COVID-19 vaccination, with greater disruption to daily life, a study has concluded. Study published in Biology of sex differences,
Johns Hopkins researchers surveyed healthcare workers (HCWs) recruited from the medical center’s mandatory fall flu vaccination campaign from 2019 to 2022 and the fall 2022 bivalent (two-strain) COVID-19 vaccination campaign. Vaccinated individuals enrolled on the day of vaccination and completed an AE survey 2 days later.
A total of 300 healthcare workers were vaccinated against the flu (50 women and 50 men per year), with AE data available for 88% of recipients (50.2% women). The mean age of flu-vaccine recipients was 30.8 years, 60.8% were white, 19.4% were Asian, 13.2% were Hispanic, and 12.9% were black.
AE data were available for 92% (76.5% women) of 212 COVID-19 vaccine recipients. The mean age was 38.4 years, 64.8% were white, 20.9% were Asian, and 8.7% were Black.
No difference in systemic side effects
Of 265 flu vaccine recipients over three years, 62% reported one or more AEs, of which 57% had only localized AEs, 21% had only systemic AEs, and 21% had both AEs.
Of the 178 flu vaccine recipients who answered the discomfort question, 80% said they had no discomfort, 17% reported mild discomfort, where they were able to perform 75% to 99% of their daily activities, 2% reported moderate discomfort, where they were able to perform 25% to 75%, and 1% said they had severe discomfort, where they were able to perform 0% to 25%.
Overall, 86% of the 196 COVID-19 vaccine recipients reported at least one AE (30% local only, 18% systemic only, and 51% both). Most (53%) reported no discomfort, 23% reported mild discomfort, 18% reported moderate discomfort, and 5% reported severe discomfort.
“Overall, these data suggest that experiencing mild AEs after vaccination is common, and has minimal impact on daily activities,” the researchers wrote.
Women were more likely than men to experience local (injection-site) AES after vaccination against the flu (likelihood ratio [OR]But rates of systemic AEs (i.e., malaise, muscle aches, insomnia, headache, fever, chills, and sweats) were similar for men and women after receiving either the flu (OR, 1.18) or COVID-19 (OR, 0.96) vaccine. Use of hormonal birth control in women of reproductive age did not significantly affect AE rates.
Gender considerations in workplace vaccination policies
Women reported more disruption to daily life than men after COVID-19 vaccination. 38.7% of women cited disruption in sleep or changes in daily routine, while 31.1% of men said so. They also said AES hinders their ability to care for their family and Women were more likely to use over-the-counter medications (24.% vs. 15.6% in men) and to schedule a COVID-19 vaccination before taking time off from work in anticipation of AE.
Further research is needed separately by sex and gender to create more equitable and effective vaccine strategies that take into account differences in AES.
“Women tend to have greater immune activation, greater antibody production, and increased T cell activation as a result of infection or vaccination, possibly making them more likely to experience AES than men,” the study authors wrote, noting that women make up about 80% of the healthcare workforce.
They added that AEs after vaccination may influence attitudes and acceptance patterns toward vaccination: “In the general population, vaccination hesitancy related to influenza and COVID-19 is higher among women than men, which we and others speculate is due to women being more likely to experience AEs than men.”
The results underscore the need for gender-inclusive policies for more effective commercial vaccination strategies, the researchers said. They concluded that “further sex- and gender-segregated research is needed to create more equitable and effective vaccine strategies that take into account differences in AES.” “The development of such strategies is important not only for seasonal vaccination planning, but also for planning effective vaccination campaigns for HCWs during pandemics.”