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.
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.