Warning of heavy bleeding during menstruation from Covid vaccines

The Spanish Agency for Medicines and Health Products (AEMPS), which reports to the Ministry of Health, has announced two new side effects of coronavirus vaccines following the publication of its eighteenth Pharmacovigilance Report: urticaria and heavy bleeding during menstruation.

In the case of urticaria – a rash with swelling, redness and itching –, this side effect has only been detected in the Moderna vaccine (renamed Spikevax) and in the cases observed, it can appear a few days after vaccination and up to about two weeks after vaccination. "It has been identified as a possible hypersensitivity reaction after receiving Spikevax, the frequency of occurrence of which is rare," the report states. This symptom appears days after vaccination and, at the latest, after 15 days. Only 292 cases have been reported in Spain.

The report notes that heavy bleeding during menstruation can occur as a possible adverse reaction in both the Moderna and Pfizer (also known as Comirnaty) vaccines. "It is a possible adverse reaction of the mRNA vaccines," AEMPS said, and they have asked that it be included in the data sheet and package leaflet of these vaccines. AEMPS said there is no evidence to suggest that these alterations have an effect on reproduction or fertility.

Around 9,000 cases of this effect have been reported worldwide in first, second or booster doses. In Spain, the number of reported cases rises to 921 with Comirnaty and 299 with Spikevax. "The available information indicates that the vast majority of these cases are transient and self-limited, without gravit," the report adds.

According to Ministry of Health data, 108,694,855 doses of Covid vaccines had been administered in Spain by 13 November, with 83,093 reports of adverse events. The most frequently reported effects continue to be general disorders of fever and malaise, nervous system disorders with reports of headache and dizziness and the musculoskeletal disorders of myalgia and arthralgia.