Moderna was aware of reports linking its vaccine to a pain associated with menstruation.Mike Blake/Reuters
A European Medicines Agency (EMA) committee on Friday recommended adding heavy menstrual bleeding to the list of side effect of mRNA COVID-19 vaccines made by Moderna, as well as Pfizer and its partner BioNTech.
Reports of heavy periods - bleeding characterized by increased volume and/or duration that interferes with the quality of life - have been observed during clinical trials, from cases in the real world and in medical literature, the EMA said.
The cases - which have mostly been non-serious and temporary in nature - have been reported after the first, second and booster doses of Pfizer-BioNTech’s Comirnaty and Moderna’s Spikevax, it added.
The regulator has now concluded that there is at least a “reasonable possibility” that heavy menstrual bleeding is causally associated with these vaccines.
A Moderna spokesperson said the company was aware of reports linking its vaccine to dysmenorrhea, or pain associated with menstruation.
“However, at this point, we have not identified a causal association with Moderna’s COVID-19 vaccine, Spikevax.”
Pfizer and BioNTech were not immediately available for comment.
The EMA also said that there was no evidence to suggest that the menstrual disorders experienced by some have any impact on reproduction and fertility.
The mRNA vaccines do not cause pregnancy complications for expectant mothers or their babies and they are as effective at reducing the risk of hospitalization and deaths in pregnant people as they are in non-pregnant people, a review carried out by the EMA’s Emergency Task Force has shown.
Overall, the totality of data continues to show that the benefits of these vaccines greatly outweigh the risks, the agency reiterated on Friday.
Menstrual disorders can occur due to a range of reasons, including underlying medical conditions as well as stress and tiredness. Health authorities have highlighted that cases have also been reported following COVID-19 infection.