Should you receive COVID-19 vaccine during pregnancy? Here’s what the experts say.

For pregnant women, the launch of COVID-19 vaccines raises agonizing questions about whether it is safer to receive the vaccine or risk infection. Despite emerging evidence that vaccines are generally safe and effective, there are virtually no data to indicate whether this is true for those waiting, although they present a higher risk of complications from the disease.

The world’s regulators have sometimes issued conflicting advice on pregnancy and COVID-19 vaccines. The Centers for Disease Control and Prevention (CDC) said vaccines should be available to pregnant women, but ultimately leave the decision to future parents and their doctors. The World Health Organization (WHO) recommends against it, unless the pregnant woman is at high risk.

So how can someone make an evidence-based decision if it is safe to receive the vaccine in the absence of any safety data? “It’s all about the features of your life,” says Ruth Faden, founder of the Johns Hopkins Berman Institute for Bioethics in Maryland. Each person must balance what It is known about the vaccine with what is known about one’s own risk of infection.

Although experts suggest talking these decisions with a health care provider, here’s a look at the facts available, what is still resolved and why there are reasons to be optimistic.

Scientists generally know quite a bit about vaccines and pregnancy – although, historically, it took longer to obtain this evidence than general safety data. Because of the ethical complexity of pregnancy – in which parents and their fetuses face interconnected risks – and fears of legal liability, pregnant women are usually excluded from randomized clinical trials that are required to obtain approval for a drug or vaccine.

In the past, years have passed since vaccines were approved for general use to gather enough data to show how they work during pregnancy. Many of these follow-up studies are observational and involve fewer participants. As a result, pregnant women may be reluctant to get vaccinated, and doctors may drop their recommendation.

“The result has been decades of injustice to pregnant women,” says Faden, who also leads the Pregnancy Research Ethics project for vaccines, epidemics and new technologies (PREVENT). Although sometimes it may make sense not to include expectant parents in early education, she says, “we have protected pregnant women to death.”

But scientists have accumulated indisputable evidence that certain vaccines are safe, effective and, in some cases, extremely necessary. Today, the CDC encourages pregnant women to get vaccinated against the flu, which is known to cause severe complications in pregnant women. Medical experts also recommend the administration of the pertussis (or whooping cough) vaccine, which can be fatal for newborns. Future people may also receive immunizations for a handful of other diseases, including hepatitis and meningitis.

Lessons from these vaccines have shown that there is no reason to worry about the types of photos that use an inactivated virus to elicit an immune response because they can infect neither parent nor child, says Geeta Swamy, associate professor of obstetrics. and gynecology at Duke University School of Medicine in North Carolina and a principal investigator in maternal immunization.

On the other hand, vaccines that use a small amount of live virus – such as measles, mumps and rubella and chickenpox – can cause low-grade infections, which some scientists worry could harm the fetus. . But, says Swamy, “even that is based on theoretical risk concerns,” not on evidence that it appears.

Moderna and Pfizer-BioNTech vaccines for COVID-19 represent a new challenge. Until now, the RNA messenger platform it uses has not been authorized for human use. As such, the only available pregnancy-related data come from preclinical studies in laboratory animals and a handful of clinical trial participants who later found out they were pregnant. (Here are the latest COVID-19 vaccines.)

But we know quite a bit about how mRNA technology works. Instead of using inactivated or live viruses, these vaccines contain fragments of the genetic code embedded in lipids or fat globules, which protect the code from degradation. Once injected, the mRNA instructs the cells to produce the SARS-CoV-2 peak protein, which triggers the body’s immune response.

Theoretically, all this is promising because, like the vaccines of the past, it does not involve a living virus. “Everything that is understood to be biological in the case of mRNA vaccines is incredibly reassuring,” says Faden. “It should have no impact on pregnancy or pregnancy outcomes.”

Anthony Fauci, chief medical officer of the White House, also said that the data “so far do not have red flags” for pregnant women.

However, scientists have raised questions about how mRNA vaccines will actually work. The biggest concern is whether mRNA can cross the placenta and generate peak protein in the fetus. It would not necessarily be harmful if it did – and did not cause birth defects – but the concern is that the fetus could have side effects, including pain, swelling and fever. Swamy says animal studies have shown no signs of physical side effects, but this has not yet been tested in humans.

Side effects in the mother can also be a problem. Christina Chambers, a perinatal epidemiologist at the University of California, San Diego, is conducting a study of pregnant women vaccinated with COVID-19. She notices that it can be harmful to the baby when a pregnant woman has a high fever. “If it’s a side effect, you’d want to pay attention to it and talk to your provider about taking something to reduce the fever,” she says.

There are ongoing clinical trials to investigate the effects of vaccines in pregnant women. Faden wants these studies to begin as soon as the vaccines have received FDA approval, but she points out that the process is even faster than in the past.

“We felt like one or two drums alone there, beating our drums in this vast silence,” she says. Now we have as a whole percussion section that requires more data and the inclusion of pregnant women in the launch of the vaccine. And this is a very good thing. ”

On the other hand, we know a lot about the risks that COVID-19 poses to future parents. “There is no doubt that pregnant women are worse than non-pregnant women,” says Swamy.

Studies have shown that people pregnant with COVID-19 have an increased risk of hospitalization, ICU hospitalization and mechanical ventilation. In January, a study was published in the journal JAMA Internal Medicine found that COVID-19 was associated with a higher chance of blood pressure problems and premature birth, although there is no higher chance of stillbirth. And an October study found that one in four pregnant people could be COVID-19 “long carriers”, whose symptoms can persist for weeks or even months.

But the risk of severe disease is lower for those expected than for other high-risk groups, such as the elderly or those with heart disease. So it is essential to look at the individual factors that increase a person’s individual risks – including the number of daily contacts, access to testing and high quality PPE and comorbidities such as asthma or obesity – and whether anything can be done to reduce them.

The timing must also be taken into account. Swamy says there is no evidence that a vaccine can cause developmental problems or miscarriage in the first trimester. But women at lower risk of infection may choose not to get vaccinated during that period, which is vital for fetal development and is when miscarriages occur. (The flu vaccine is safe at any time during pregnancy.)

For pregnant women who are at high risk of exposure and do not have the option to reduce this risk, it may make sense to consider taking the vaccine as soon as they are eligible. But to find out for sure, says Chambers, “the urgency is to get data on people being vaccinated.”

There is reason to hope that scientists will soon have a better understanding of how COVID-19 vaccines work during pregnancy. In the short term, scientists are looking forward to the data from pregnant workers who started getting the vaccines in December. Faden says the data should be solid, as more than 15,000 vaccinated pregnancies have been reported to the CDC since Jan. 20.

Beyond mRNA vaccines, there are several new options on the horizon. Johnson & Johnson presented its vaccine for FDA approval on Feb. 4, while AstraZeneca and Novavax recently released critical phase data from study three. All three vaccines are based on technologies that have been studied in the past in pregnant women, which Swamy says could provide additional insurance. (Should people get more COVID-19 vaccine?)

Recent studies have also suggested that vaccination during pregnancy may have additional benefits. A study published in the journal JAMA Pediatrics showed that women who were infected with COVID-19 effectively transfer protective antibodies to their children – especially if they are infected earlier in pregnancy. The study does not suggest that this transfer will take place after vaccination, notes co-author Karen Puopolo, who visits the neonatologist at Pennsylvania Hospital. But Swamy says it’s good news that antibodies regularly cross the placenta in natural infection and that vaccination is expected to have a similar response.

“She tells us that vaccinating women could have that type of two for the price of one,” she says, “that by vaccinating women we also offer some benefits during early childhood.”