Pratiksha Bhattarai

At present, vaccines have become the most viable option in the battle against COVID-19. Nowadays, it is common to see vaccination centres overwhelmed by huge crowds seeking to receive their vaccine doses. Safe and effective vaccines can be a game-changer. Yes, everyone agrees to this, however, with more and more people being vaccinated, each of them is reacting differently to the effects and side effects of vaccines.
For COVID-19, there are mainly four types of vaccines: genetic, inactivated, attenuated and viral vector vaccines. Each of these vaccines works differently to introduce antigens in our body so that they can respond to build memory and fight against the virus.

Side Effects
Typical side effects include pain at the injection site, fever, fatigue, headache, muscle pain, chills and diarrhoea. Talking about the contraindications, these vaccines are not advisable for children under 18, as these vaccines have not been tested in these groups.
Similarly, those who had any form of allergic reaction to the COVID-19 vaccine previously should not use the vaccine. Those with an immediate allergic reaction to any vaccine or injectable therapy not related to a coronavirus vaccine component are relatively contraindicated.
It is not recommended for pregnant women. Experts suggest there is no foreseeable risk for breastfeeding women or the infant, and that those who became pregnant after receiving the vaccine are at no increased risk of harm. A preliminary report from the largest study on vaccine safety in pregnant women shows that Pfizer's and Moderna's vaccines are safe to be used during pregnancy.
However, along with the introduction of vaccines, different rumours, myths and hesitations came along. The public looked perplexed to either get vaccinated or not. Women, as we know, are at different phases of life - some planning to conceive, pregnant, postnatal, lactating, and some menstruating, in their teens or elderly remained puzzled. While most of these women choose not to vaccinate, the menstruating group remained baffled whether to receive vaccination or not.
As more and more women started receiving their first or second doses, some women started to report changes in their periods following the vaccine. Following the post on Twitter regarding her experience on post-vaccination menstruation, Dr Kate Clancy, an associate professor of anthropology at the University of Illinois, received several responses from females who experienced irregularities in their cycle. It was surprising to see a woman in menopause sharing that she had menstruation like bleeding in 28 months. Another lady reported that she had to have a blood investigation done as advised by her doctor for her unusual bleeding, while a third said she started her period in the middle of birth control pills - something that had never happened to her in 12 years of taking the pills.

Different Experiences
Furthermore, some women reported that their periods arrived earlier and the flow was much heavier than usual, while others reported changes in their menstruation cycle not after getting vaccinated but after contracting COVID-19 itself. Meanwhile, the stories from Israel as reported by Israeli women in newspapers revealed that they had been experiencing irregular menstrual cycles and abnormal vaginal bleeding after getting a vaccination.
These preliminary experiences shared by women with the help of social media are anecdotal; however, robust research can validate these claims. A person’s hormones are connected to their immune response. These changes appear to be temporary, with cycles returning to normal in a couple of months. That’s good news, and researchers are still working to understand more about why some women are experiencing these changes.
There are many reasons why vaccination could alter menstruation. The menstrual cycle involves timed series of hormones, including estrogen and progesterone, spiking and falling in preparation for a potential pregnancy. This means that periods also involve the immune system. The thickening and thinning of the uterine lining are facilitated by the various group of immune cells and the process of shedding this lining during menstruation is a part of the inflammatory response.
Since the cycle is immune-mediated, it is possible that the vaccines, which are designed to influence immune response, temporarily change the normal course of events. For example, an activated immune system might interfere with the usual balance of immune cells and molecules in the uterus. These disturbances can bring changes in periods, including heavy menstrual bleeding.
But no one can say whether this may explain potential post-vaccine disruptions to the menstrual cycle or not. To highlight the facts, we would need a controlled study with a placebo group. Clinical trials, including those for vaccines, typically omit the tracking of menstrual cycles, so we lack the evidence and it is very challenging to put these reports in context as there are a few mammals who menstruate, which makes the subject harder to study in animals. With various studies and ongoing research, experts say that, so far, no data is linking the vaccines to changes in menstruation. Even if there is a connection, one unusual period is not alarming.

Harmless
One does not need to reschedule the vaccination date depending on the periods. Notably, all women above 18 years of age irrespective of their periods, should get vaccinated. Recently, the American College of Obstetricians and Gynecologists(ACOG) has recommended that COVID-19 vaccines should be offered to all women irrespective of whatever phase of life they are facing be it pre-conception, pregnancy, lactating, post-natal or menstruation. For now, much work is needed to be done to shed light on this. It is adorable that the conversation on the vaccination and menstruation has begun, and women seem to be openly sharing their concerns.
In general, a variety of factors including changes in diet, weight, exercises', stress level and lack of sleep affect a women's menstrual cycles. Women typically mount a greater immune response to vaccines than men, which means they may react differently after any vaccination. The bottom line is that there is scarce evidence to show that the vaccine itself could affect menstrual cycles and even if it does, it is unlikely to have any effects on fertility or long-term effects.

(Bhattarai is a maternal and newborn health researcher. patriksha@gmail.com)