Menstrual Adverse Events Post COVID-19 and HPV Immunization

Some women are experiencing menstrual adverse events including heavier bleeding following Coronavirus disease 2019 (COVID-19) spike immunization. The etiology of these menstrual adverse events associated with COVID-19 spike immunization remains unknown. The United States Department of Health and Human Services Vaccine Adverse Event Reporting System (VAERS) database was retrospectively analyzed for data reported adverse events affecting menstrual cycles by vaccine. Elevated normalized frequencies for menstrual adverse events were detected for multiple vaccines, including COVID-19 vaccines and human papillomavirus (HPV) vaccines. Lower normalized frequencies were detected for both COVID-19 bivariant vaccines and the HPV Gardasil 9 vaccines compared to higher normalized frequencies for COVID-19 Pfizer-BioNTech, COVID-19 Moderna, HPV Cervarix, and HPV Gardasil vaccines. Chi-squared 2x2 statistically significant differences in normalized frequencies were observed between different COVID-19 Pfizer-BioNTech lots (p < 0.00001) and also COVID-19 Moderna lots (p < 0.00001). Manufacturing contaminants (e.g., endotoxins) are likely candidates consistent with the observed data for reported menstrual adverse events.