European Medicines Agency investigates possible menstrual issues linked to COVID vaccines

The European Medicines Agency’s safety committee said it was reviewing reports of heavy menstrual bleeding and absence of menstruation from women who had received COVID vaccines from Pfizer/BioNTech and Moderna.

The EMA’s Pharmacovigilance Risk Assessment Committee (PRAC), which oversees the safety of medicines, is carrying out the assessment.

It will review all available evidence on mRNA vaccines and period changes among women, including reports from vaccinated women, clinical trials and studies.

The assessment comes after reports surfaced of menstrual disorders after receiving either of the two vaccines, both based on messenger RNA technology.

However, it is not yet clear whether there is any a causal link between the vaccines and the reports, the agency said.

Menstrual disorders can occur as a result of a range of underlying medical conditions as well as from stress and tiredness, the EMA said, adding that cases of such disorders had also been reported following COVID-19 infection.

Vaccination against COVID-19 was linked with a small, temporary change in menstrual cycle length, according to a recent study funded by the National Institutes of Health, which collected data from nearly 4,000 users of a smartphone app that tracks menstrual cycles.

However, the EMA said in December it had not established a link between changes in menstrual cycles and COVID-19 vaccines, after a study in Norway suggested some women had heavier periods after being inoculated.

Other studies have also found only minor effects as a result of COVID vaccination.

A recent study of more than 4,000 women in the US found periods lasted 15 hours longer in women who had a first dose and 19 hours longer among double-jabbed.

However, the Oregon Health and Science University scientists leading the study said the changes were ‘small’ and ‘temporary’.

And an Imperial College London study of 1,200 women also revealed no definitive link between period changes among vaccinated women.

The EMA added that there was also no evidence to suggest that COVID-19 vaccines affected fertility.

In a statement Pfizer said: “We will support the EMA Pharmacovigilance Risk Assessment Committee (PRAC) in its evaluation to determine whether there is a causal relationship between COMIRNATY and reports of menstrual irregularities. Abnormal menstruation was not a reported adverse event in the BNT162b2 phase 3 clinical trial; we continue to monitor trial participants’ health for two years after they receive their vaccinations. Menstrual irregularities and disorders are very common and can occur with a wide range of underlying medical conditions as well as from lifestyle changes such as stress and tiredness. Cases of these irregularities have also been reported following COVID-19 infection.”

Moderna did not respond to requests for comment from Emerging Risks.

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