The possible link between CCP virus vaccinations and menstrual changes should be investigated to clear up the doubts, a reproductive immunology lecturer from Imperial College London said.
According to the editorial, by Sept. 2 more than 30,000 cases of menstrual disorders and unexpected vaginal bleeding after vaccination had been reported in the UK to the Medicines and Healthcare products Regulatory Agency’s (MHRA) yellow card surveillance scheme for adverse drug reactions.
The document says the number of reports of menstrual disorders and vaginal bleeding were low in relation to both the number of people who have received CCP virus vaccines to date and how common menstrual disorders are generally.
It also said the reported disorders were mostly transient in nature and that there had been no evidence to suggest that the vaccines would affect fertility and the ability to have children.
Male corroborated MHRA’s statement, saying most reported post-vaccine menstrual disorders only occurred for a single cycle before they returned to normal.
She also added that both unintended pregnancy rates and pregnancy rates in assisted reproduction clinics have been similar in vaccinated and unvaccinated patients in clinical trials.
However, Male argues that further investigation will be needed to eliminate uncertainties.
The yellow card scheme relies on voluntary reporting of suspected side effects or medical device incidents to be reported by health professionals and the public, including patients, carers, and parents.
Male said the nature of the system’s information collection method makes it difficult to draw firm conclusions.
The reproductive immunology lecturer suggested that she doesn’t believe the vaccines affect women’s fertility based on the evidence available.
Three CCP virus vaccines are currently available in the UK. Two of them—Pfizer-BioNTech and Spikevax (developed by Moderna)—are mRNA vaccines, while the Oxford-AstraZeneca jab is an adenovirus vectored vaccine.
The menstrual changing events occurred across all three vaccines. Male said it suggests that if there is a connection between the vaccines and menstrual disorders, it’s likely to be a result of the immune response to vaccination rather than a specific vaccine component.
According to Male, menstrual cycles can be affected by immune activation in response to various stimuli, such as other vaccines and viral infections, including CCP virus infection.
In one study of menstruating women, around a quarter of those infected with the CCP virus experienced menstrual disruption, the editorial said.
Male believes an investigation may also help understand the mechanism behind the menstrual changes following vaccinations, and it will also help clear any unnecessary fears and mistrust towards the vaccines.
“Although reported changes to the menstrual cycle after vaccination are short-lived, robust research into this possible adverse reaction remains critical to the overall success of the vaccination programme,” she wrote.
Dr. Jo Mountfield, vice president of the Royal College of Obstetricians and Gynaecologists, said the college wants to “reassure women that any changes generally revert back to normal after one or two cycles,” but it also supports calls for more research into the possible association.
The MHRA said period problems can be caused by stressful life events and added that changes to the menstrual cycle have also been reported after people have had the virus or are suffering from so-called long-COVID.
Dr. Alison Cave, chief safety officer at the MHRA, said they are “closely monitoring reports of suspected menstrual disorders” through the “robust” yellow card scheme.
“As outlined in our vaccine safety surveillance strategy, the yellow card scheme is one of several sources of evidence we use when evaluating the safety of vaccines,” she said.
“Based on our current rigorous safety monitoring, women can be reassured that the current evidence does not show a link with any changes in women’s periods or symptoms, nor is there any evidence to suggest that COVID-19 vaccines will affect fertility. This is also the conclusion of our expert scientific advisory committee, the Commission on Human Medicines,” Cave said in a statement.
“Whilst uncomfortable or distressing, period problems are extremely common and stressful life events can disrupt women’s periods. Changes to the menstrual cycle have also been reported following infection with COVID-19 and in women affected by long-COVID,” she added.
“Our advice remains that the benefits of vaccination outweigh the risks for most people.”
