Shana Clauson was in line to get her first dose of the Moderna shot in March when she saw menstruators on social media discussing how their periods had been altered – earlier, heavier and more painful than usual – after they got their coronavirus vaccinations.

Clauson, a 45-year-old who lives in Hudson, Wis., went ahead and got the shot – and, a few days later, also got an earlier and heavier period than she was used to. A few weeks later, in early April, she told The Washington Post that she was frustrated with the lack of research on whether the vaccines impacted menstrual cycles.

“Is this not being discussed, or is it even being looked at or researched because it’s a ‘woman’s issue?’ ” Clauson asked at the time. “I hope that if this is going to be a side effect for women, that it’s being addressed and women know this could happen.”

Last week, she got her wish: The National Institutes of Health has awarded $1.67 million to researchers at five institutions to study potential links between coronavirus vaccinations and menstruation, the agency announced Aug. 30.

Combined, the five NIH-funded studies – conducted by researchers at Boston University, Harvard Medical School, Johns Hopkins University, Michigan State University and Oregon Health and Science University – will likely incorporate between 400,000 and 500,000 participants, including adolescents and transgender and nonbinary people, according to Diana Bianchi, director of the agency’s Institute of Child Health and Human Development, which is funding the research along with NIH’s Office of Research on Women’s Health.

The year-long studies will exclusively incorporate participants who have not yet been vaccinated – both those who intend to be as well as those who don’t – to be able to study possible changes to their menstrual cycle before and after vaccination, Bianchi said.

“Our goal is to provide menstruating people with information, mainly as to what to expect, because I think that was the biggest issue: Nobody expected it to affect the menstrual system, because the information wasn’t being collected in the early vaccine studies,” said Bianchi, who credited The Post’s early coverage of the issue, in April, with first making her and her staff aware of it.

The researchers hope that, following a peer review process, findings will be published by the end of 2022 or soon after.

The news of the forthcoming research came later than Clauson would’ve liked – but better late than never, she said: “I’m glad that it’s going to be looked at. I think it’s unfortunate that it took this long.”

Menstrual changes after coronavirus vaccinations could be attributed to immune responses to the vaccines and their impacts on the uterus, as well as to pandemic-related stress, lifestyle changes and contracting the virus itself, according to the National Institutes of Health. But so far, no published studies have examined – or offered conclusive evidence – of possible linkages between the vaccines and menstruation.

The coronavirus vaccine trials did not specifically ask participants whether they saw adverse side effects in their menstrual cycles or volumes – an omission that Bianchi attributes to the fact that “the (FDA) emergency use authorization was really focused on critical safety issues” and “changes to your menstrual cycle is really not a life and death issue,” she said.

But the lack of formal research on the potential link between the two “points out the fact that safety studies for vaccines … are not necessarily thinking about the reproductive health of women,” Bianchi added. “We hope that one of the things that’s going to come out of this is that questions will be added to clinical trial studies to include any changes in menstrual health.”

The NIH funding “signifies that they’re recognizing that there’s an important gap in our understanding of how vaccines influence menstrual health and ultimately reproductive health,” according to Leslie Farland, an assistant professor in the department of epidemiology and biostatistics at the University of Arizona’s College of Public Health, who is researching the impacts of the vaccinations on Arizona women but said she did not apply for the NIH funding.

Three of the five NIH studies will exclude participants who are on birth control or gender-affirming hormones due to the possible impacts of those hormones on menstrual patterns and flow. Researchers in the two studies that will allow participants on hormones – at Johns Hopkins and Michigan State – will need to consider those possible impacts in their analyses, according to Linda Huynh, a science writer for the National Institute of Child Health and Human Development.

Funding typically takes a year or two to approve, but Bianchi’s staff published a call for funding applications in May, with a June deadline, given the demand for answers and concern among menstruators, Bianchi said: “There was an urgency to it, the fact that this was getting so much attention. We were worried this was contributing to vaccine hesitancy in reproductive-age women.” Researchers say there is no evidence that the vaccines cause infertility, and the Centers for Disease Control and Prevention recommends pregnant people get vaccinated.

Earlier this year, a number of women and menstruators took to Facebook groups and Reddit threads to share their accounts of their post-vaccination periods. A Twitter thread authored by Kate Clancy, an associate professor of anthropology who studies reproductive justice at the University of Illinois, attracted more than 1,000 responses from menstruators about how their cycles were altered following their vaccinations – another source of information that Bianchi said was crucial in shaping the agency’s understanding of the prevalence of the issue.

(Clancy and Katharine Lee, a postdoctoral scholar in the division of public health sciences at Washington University, are co-leading the first study that was designed to specifically look at linkages between the vaccines and menstruation, which has more than 150,000 English and Spanish-speaking respondents, according to Lee. The pair applied for the NIH funding but were not successful. Bianchi said information about unsuccessful applications is confidential.)

The funding was awarded to researchers who were already conducting research on menstruation and reproductive health with NIH-funded grants, Bianchi said.

One of those includes Laura Allen Payne, an assistant professor of psychiatry at Harvard Medical School who is leading a two-year study on adolescent girls’ menstrual pain. That age group is crucial to study, Payne said, given that they’re “at risk for potential hormonal, biological and neurological changes that could put them at risk for (chronic) pain,” which affects women on average more than men, according to a 2016 CDC study.

Within that larger study, Payne will focus on the menstrual cycles of about 80 girls before and after they get vaccinated to determine if and how the vaccines impact their cycles – and, potentially, their pain, she said.

Three of the other research projects – at BU, Johns Hopkins and OHSU – will partner with period-tracking apps Clue, Natural Cycles and Kindara, which will provide researchers with de-identified data from users who have consented to participate, according to Bianchi.

Stacey Missmer, a professor of obstetrics, gynecology and reproductive biology at Michigan State University, will use the funding to expand two studies she’s leading that are already underway – on infertility and endometriosis – to determine whether the vaccines and pandemic-related stress and anxiety are impacting periods.

Missmer characterizes the research funding as crucial to combating vaccine-related misinformation by offering menstruators clear answers, supported by evidence, to their questions about the vaccines’ impacts. “Anytime we can clarify what people can expect and understand better what the impacts of any changes are, hopefully that will help to decrease vaccine hesitancy,” she said.

The coronavirus vaccines are not the first vaccines to lead menstruators to report changes to their cycles, according to Farland, the Arizona researcher who is not involved with the NIH studies.

Farland pointed to a study published last year that found that the CDC’s Vaccine Adverse Event Reporting System – a national vaccine safety surveillance program to which anyone can submit their reports of post-vaccine side effects – included disproportionate reports of menstrual irregularities, among other reproductive health issues, following HPV vaccinations. (That database also includes more than 3,700 reports of menstruation discomfort, delays, disorders and irregularities following coronavirus vaccinations. The CDC’s Vaccine Safety Datalink, a collaborative project between the agency’s Immunization Safety Office and nine health-care organizations that monitors the safety of vaccines, is exploring the feasibility of conducting a study of menstrual irregularities following coronavirus vaccinations, according to CDC spokesperson Martha Sharan.)

Another study that Farland pointed to, dating back to 1913, found that a little more than half of 100 women who received the typhoid vaccine experienced some sort of disturbance to their cycle – including having longer, earlier, missed or more painful periods – and that 14 of those cases saw “very distinct changes” to the menstrual cycle, including multiple altered cycles in the months following vaccination.

But even so, “information on reproductive health has not been historically collected in our vaccine trials and in our current vaccine surveillance system,” Farland said – in part, because it was not until 1993, when the Revitalization Act was signed into law, that the NIH established federal guidelines requiring “women and minorities” to be included in clinical research.

“Ultimately, I think we need to know whether or not these (menstrual) changes exist, how severe these changes are, and the duration of these changes so that we can better counsel individuals who are menstruating about what to expect,” Farland added.

The fact that this funding ultimately came as the result of menstruators taking to social media and speaking up about their experiences, Clauson said, shows that “we have to stand up for ourselves.”

As she put it: “It just feels like that’s how we have to get stuff done when it comes to our well-being and our health, because it is so often ignored.”