Menstrual cycle changes increased following COVID-19 mRNA vaccination: Social media validation and self-controlled case series analysis.

ObjectivesTo investigate if there was an increase in menstrual abnormality related presentation post COVID-19 vaccination. DesignBERTopic machine learning, with a guided topic modelling option was used to analyse mentions of menstrual change in relation to COVID-19 vaccination on the social media platform Reddit. Self-controlled case series (SCCS) analysis using general practice data collected via the POpulation Level Analysis and Reporting (POLAR) tool with permission from Primary Health Networks (PHNs) as the de-identified dataset owners in Victoria and New South Wales. SettingGlobally for social media analysis. Victoria and New South Wales (NSW), Australia for POLAR ParticipantsFor social media analysis, people who made a Reddit post about menstrual concerns post COVID-19 vaccine. For the SCCS analysis, people who presented to a POLAR GP registered practice with a new menstrual abnormality diagnosis. ExposuresCOVID-19 vaccination with adenovirus vector [AstraZenecas Vaxzervria(R) ChadOx1-S], mRNA [Pfizer-BioNTechs Comirnaty(R) BNT162b2 and Modernas Spikevax(R)] or protein-subunit [Novavaxs Nuvaxovid(R)]). Outcomes and MeasuresScraped social media posts were pre-processed, analysed for positive, negative, and neutral sentiments and topic modelled. Menstrual abnormality presentations of interest were isolated from the general practice dataset aggregated by POLAR, by searching for relevant SNOMED CT codes. Similarly, relative incidence (RI) was calculated for all COVID-19 vaccine types. ResultsSocial media analysis saw peaks in menstrual change posts on Reddit since the global COVID-19 vaccine rollout. The SCCS analysis demonstrates an increase in general practice presentations of menstrual abnormality diagnosis following mRNA vaccines (RI= 1.14, 95% CI: 1.07 to 1.22, P <0.001). Conclusions and RelevanceThis study demonstrates an increase in menstrual abnormality presentations following COVID-19 mRNA vaccination. Our findings validate the concerns raised on social media so people who are vaccinated or are considering future vaccines feel heard, supported, and validated. Our analysis highlights the importance of using large real-world datasets to gather reliable evidence for public health decision making. Summary box O_TEXTBOXSection 1: What is already known on this topic?O_LISurveys and spontaneous surveillance systems suggested and association of menstrual cycle changes with COVID-19 vaccination. C_LIO_LIHeavy menstrual bleeding was added to the product information for mRNA vaccines in the European Union C_LI Section 2: What this study adds?O_LIOur study is the first to prove an increase in menstrual abnormality related presentations post mRNA COVID-19 vaccines using routinely collected general practice data. C_LIO_LIOur findings validate the concerns raised by people who menstruate and help them with their future decision to vaccinate. C_LI C_TEXTBOX