ABSTRACT
BACKGROUND: Despite anecdotal reports, the impacts of SARS-CoV-2 infection or COVID-19 vaccination on menstrual health have not been systemically investigated. OBJECTIVE: This study aimed to examine the associations of SARS-CoV-2 infection and COVID-19 vaccination with menstrual cycle characteristics. STUDY DESIGN: This study prospectively observed 3858 premenopausal women in the Nurses' Health Study 3 living in the United States or Canada who received biannual follow-up questionnaires between January 2011 and December 2021 and completed additional monthly and quarterly surveys related to the COVID-19 pandemic between April 2020 and November 2021. History of positive SARS-CoV-2 test, COVID-19 vaccination status, and vaccine type were self-reported in surveys conducted in 2020 and 2021. Current menstrual cycle length and regularity "before COVID-19" were reported at baseline between 2011 and 2016, and current menstrual cycle length and regularity "after COVID-19" were reported in late 2021. Pre- to post-COVID change in menstrual cycle length and regularity was calculated between reports. Logistic or multinomial logistic regression models were used to assess the associations between SARS-CoV-2 infection and COVID-19 vaccination and change in menstrual cycle characteristics. RESULTS: The median age at baseline and the median age at end of follow-up were 33 years (range, 21-51) and 42 years (range, 27-56), respectively, with a median follow-up time of 9.2 years. This study documented 421 SARS-CoV-2 infections (10.9%) and 3527 vaccinations (91.4%) during follow-up. Vaccinated women had a higher risk of increased cycle length than unvaccinated women (odds ratio, 1.48; 95% confidence interval, 1.00-2.19), after adjusting for sociodemographic and behavioral factors. These associations were similar after in addition accounting for pandemic-related stress. COVID-19 vaccination was only associated with change to longer cycles in the first 6 months after vaccination (0-6 months: odds ratio, 1.67 [95% confidence interval, 1.05-2.64]; 7-9 months: odds ratio, 1.43 [95% confidence interval, 0.96-2.14]; >9 months: odds ratio, 1.41 [95% confidence interval, 0.91-2.18]) and among women whose cycles were short, long, or irregular before vaccination (odds ratio, 2.82 [95% confidence interval, 1.51-5.27]; odds ratio, 1.10 [95% confidence interval, 0.68-1.77] for women with normal length, regular cycles before vaccination). Messenger RNA and adenovirus-vectored vaccines were both associated with this change. SARS-CoV-2 infection was not associated with changes in usual menstrual cycle characteristics. CONCLUSION: COVID-19 vaccination may be associated with short-term changes in usual menstrual cycle length, particularly among women whose cycles were short, long, or irregular before vaccination. The results underscored the importance of monitoring menstrual health in vaccine clinical trials. Future work should examine the potential biological mechanisms.
ABSTRACT
Objectives. To characterize COVID-19 vaccine uptake and hesitancy among US nurses. Methods. We surveyed nurses in 3 national cohorts during spring 2021. Participants who indicated that they did not plan to receive or were unsure whether they planned to receive the vaccine were considered vaccine hesitant. Results. Among 32 426 female current and former nurses, 93% had been or planned to be vaccinated. After adjustment for age, race/ethnicity, and occupational variables, vaccine hesitancy was associated with lower education, living in the South, and working in a group care or home health setting. Those who experienced COVID-19 deaths and those reporting personal or household vulnerability to COVID-19 were less likely to be hesitant. Having contracted COVID-19 doubled the risk of vaccine hesitancy (95% confidence interval [CI] = 1.85, 2.53). Reasons for hesitancy that were common among nurses who did not plan to receive the vaccine were religion/ethics, belief that the vaccine was ineffective, and lack of concern about COVID-19; those who were unsure often cited concerns regarding side effects or medical reasons or reported that they had had COVID-19. Conclusions. Vaccine hesitancy was unusual and stemmed from specific concerns. Public Health Implications. Targeted messaging and outreach might reduce vaccine hesitancy. (Am J Public Health. 2022;112(11):1620-1629. https://doi.org/10.2105/AJPH.2022.307050).