This study finds a surge of Google searches related to vaccine and the menstrual cycle following the initiation of national and state-level COVID-19 vaccination drives. While it may suggest that COVID-19 vaccines could affect menstrual regularity, it could also reflect the mere concerns of those not yet vaccinated. We also find that TikTok hashtag #periodproblems peaked at the beginning of the pandemic in March 2020, and again with the initiation of vaccination programs, early in 2021. This reflects menstrual irregularities being either a consequence s of the vaccine or a significant worry regarding such consequences, yet practically rules out claims that concerns about the menstrual cycle are merely an effect of pandemic-related stress.
The safety of COVID-19 vaccines in pregnancy and lack of discernable effects on fertility have been recently shown in several reports14,15. Studies of the possible effects of COVID-19 vaccines on menstruation have been initiated through questionnaires, doctors' reports and other experimental strategies16. However, these studies encompass limited amounts of data in comparison to that available by monitoring web and social media activity. Moreover, studies based on physicians' reports are lacking since women do not often report menstrual irregularities to their physicians, because of discomfort or inconvenience of going to the doctor, especially during the pandemic8. Our findings reflect menstrual cycle irregularities as a major worry of women in considering compliance with vaccination programs, suggesting possible effects of the vaccine on such irregularities, and highlight a clear need for scientifically sound studies testing possible effects of the vaccines on menstruation. Of note, our analysis deals with relative search volumes. Thus, significant changes in other searches at the same time and place might mask or distort the results.
This study highlights the use of an array of social media big data analyses, combining Google Trends and TikTok (representing a significantly younger cohort), in identifying public trends preventing vaccine compliance across different states and countries. Prior studies proved retrospectively through Google trends facts that were previously known, such as the initiation of the pandemic or effects of COVID-19 disease on smell. In contrast, this study highlights social media big data analysis as an effective massive-scale tool in the initial identification and determination of adverse effects (as well as positive effects) of the COVID-19 vaccine. Moreover, it verifies the findings across various states in the U.S. and other countries, ruling out effects of local trends, climates, publicities and regulations, as well as enables delineation of different effects of the various COVID-19 vaccines given in different states or countries. Thus, web and social media analyses enable improved strategies in identifying public health concerns and determining public health policies to improve vaccine compliance.