Last December, I cried into my mask on the subway home after getting the only holiday gift I wanted: the Pfizer vaccine. As a gastroenterologist treating hospitalized Covid patients, it brought back a flood of difficult memories from the past year. Among the most haunting were the pregnant people with severe liver injury I cared for in the intensive care unit who couldn’t see their newborns.
Two months later, I became pregnant myself.
The pandemic has transformed pregnancy, an already stressful life event, into a unique minefield. Pregnant people faced early bans on hospital visitors during labor, exclusion from the original vaccination studies and disproportionate devastation from the Delta variant, which in August cost 22 lives — the highest number of Covid-19 deaths in a single month among pregnant people since the pandemic started.
Since January 2020, at least 180 pregnant people have died from Covid-19. The recent pleas from federal health officials for all pregnant people to get vaccinated as soon as possible has provided the kind of no-nonsense clarity that expecting parents might have been waiting for. But what does that mean for boosters?
The Centers for Disease Control and Prevention lists pregnancy as a medical condition that would make someone eligible for a Covid-19 booster. Official guidelines firmly declare that you “should” get a booster if you meet certain criteria — for instance if you work in a high-exposure field, like as a nurse or teacher (both professions that incidentally make up the two most common occupations for pregnant workers in the United States). But the guidelines recommend that people who fall into other high risk categories, including those who are pregnant, weigh the individual risks and benefits of the booster.
This can leave many pregnant people like myself wondering if they should rush to get a third shot. Dr. Dana Meaney-Delman, the lead scientist for maternal Covid-19 immunization at the C.D.C., has been considering these questions carefully. “There’s nothing to suggest boosters are a safety issue. We have great confidence in these vaccines,” she said, adding that anyone who is pregnant, postpartum, considering pregnancy or who might be pregnant in the future should get the vaccine. “That’s the most urgent message,” she said.
She noted that, as an OB-GYN herself, she encourages a third dose for her pregnant patients. “From a biological plausibility perspective, there’s really no reason not to recommend a booster,” she said.
The American College of Obstetricians and Gynecologists, as well as the Society for Maternal-Fetal Medicine, also did not mince words in the advisories they updated on Oct. 1: Yes, pregnant people who completed the Pfizer-BioNTech vaccine series at least six months ago should get the booster shot. (Other vaccines will likely soon be authorized as boosters.)
Their recommendations underscore the risks of severe consequences from Covid-19 during pregnancy, as well as evidence of waning immunity.
Many experts suggest that pregnant people are not so much immunocompromised, as once believed, but that their immune systems change in unique ways during each stage of pregnancy, opening windows of vulnerability to Covid-19. Besides these changes, the physical demands of pregnancy — the growing fetus’ strain on the diaphragm and lungs, the increased strain on the cardiovascular system — put pregnant people at higher risk of being hospitalized and dying from Covid-19 without the vaccine.
Signing up for a booster shot might also help the unborn baby. Dr. Andrea Edlow, an OB-GYN and researcher at Massachusetts General Hospital, demonstrated that the immune response induced by Covid-19 mRNA vaccines in pregnant and lactating women was far greater than the response produced by a coronavirus infection. They also found that those antibodies were robustly passed to the fetus through the placenta, as well as through breast milk.
Although countries like Israel and most recently the United States have started giving booster shots to pregnant people, experts are still collecting data on their outcomes. It might be months, or more, before we have more information.
Nonetheless, there is no reason to expect that the booster side effects in pregnant people will be different than those in the general population, according to Dr. Meaney-Delman, who led a C.D.C. study on vaccinations in pregnancy.
The study, which analyzed the self-reported side effects from more than 35,000 pregnant people, demonstrated that vaccine reactions were similar among pregnant women compared with nonpregnant women. Among the most common were pain at the injection site and fatigue.
What to Know About Covid-19 Booster Shots
The F.D.A. authorized booster shots for a select group of people who received their second doses of the Pfizer-BioNTech vaccine at least six months before. That group includes: vaccine recipients who are 65 or older or who live in long-term care facilities; adults who are at high risk of severe Covid-19 because of an underlying medical condition; health care workers and others whose jobs put them at risk. People with weakened immune systems are eligible for a third dose of either Pfizer or Moderna four weeks after the second shot.
Regulators have not authorized booster shots for recipients of Moderna and Johnson & Johnson vaccines yet. A key advisory committee to the F.D.A. voted unanimously on Oct. 14 to recommend a third dose of the Moderna vaccine for many of its recipients. The same panel voted unanimously on Oct. 15 to recommend booster shots of Johnson & Johnson’s one-dose vaccine for all adult recipients. The F.D.A. typically follows the panel’s advice, and should rule within days.
The C.D.C. has said the conditions that qualify a person for a booster shot include: hypertension and heart disease; diabetes or obesity; cancer or blood disorders; weakened immune system; chronic lung, kidney or liver disease; dementia and certain disabilities. Pregnant women and current and former smokers are also eligible.
The F.D.A. authorized boosters for workers whose jobs put them at high risk of exposure to potentially infectious people. The C.D.C. says that group includes: emergency medical workers; education workers; food and agriculture workers; manufacturing workers; corrections workers; U.S. Postal Service workers; public transit workers; grocery store workers.
For now, it is not recommended. Pfizer vaccine recipients are advised to get a Pfizer booster shot, and Moderna and Johnson & Johnson recipients should wait until booster doses from those manufacturers are approved. The F.D.A. is planning to allow Americans to receive a different vaccine as a booster from the one they initially received. The “mix and match” approach could be approved once boosters for Moderna and Johnson & Johnson recipients are authorized.
Yes. The C.D.C. says the Covid vaccine may be administered without regard to the timing of other vaccines, and many pharmacy sites are allowing people to schedule a flu shot at the same time as a booster dose.
Regarding timing, the sooner you get a booster during your pregnancy, the better, Dr. Edlow said. Not only does an earlier booster likely mean a lower chance of a breakthrough infection (which could increase the risk of preterm birth), but, as is the case with other recommended vaccines in pregnancy, an earlier shot could translate to more antibodies passed to the fetus.
Waiting until just before delivery means you will have lower antibody levels, “and you don’t have as much time for the antibodies to transfer across the cord, so it’s just less effective,” Dr. Edlow said. “You’re going to give your baby the best protection if you do it earlier.”
Another reason eligible pregnant people shouldn’t wait to get a booster is that the types of antibodies that pass through the umbilical cord are different from those that pass through breast milk. The blood-borne antibodies that cross the umbilical cord are much longer lasting than those primarily passed through breast milk, Dr. Edlow said. By getting the booster during pregnancy, the baby gets the benefit of both.
In the end, I decided to receive the booster shot two weeks ago at 33 weeks pregnant. I had some fatigue (and took a nap in the evening) as well as muscle aches the next day. By the following morning, I felt completely back to normal.
“You shouldn’t think, ‘I need to get boosted or I’m going to die from Covid.’ That’s the rationale for the first vaccine doses,” Dr. Edlow said. The booster, however, can prevent pregnant people from symptomatic illness or from transferring the virus to young children at home in addition to providing protection to their newborns.
“I don’t think there are any special considerations. I think they should just go get the booster,” she said.
Dr. Trisha Pasricha is a writer and physician at Massachusetts General Hospital. Her work has appeared in the Washington Post, the Los Angeles Times and The Atlantic.