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

For people who are pregnant, the launch of the COVID-19 vaccines is raising agonizing questions about whether it is safer to get the vaccine or whether there is a risk of infection. Despite the emerging evidence that vaccines are generally safe and effective, there is virtually no data on whether this is true for those who are pregnant, although they are at a higher risk of complications from the disease.

Regulatory bodies around the world have sometimes issued mixed advice on pregnancy and COVID-19 vaccines. The Centers for Disease Control and Prevention (CDC) said that vaccines should be available for pregnant women, but ultimately leaves the decision to future parents and their doctors. The World Health Organization (WHO) does not recommend it, unless the pregnant person is at high risk.

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

Although experts suggest talking These decisions with a medical provider, here is a look at the facts available, what is still being resolved and why there are reasons to be optimistic.

Scientists generally know a lot about vaccines and pregnancy – although it has historically taken longer to obtain this evidence than general safety data. Due to the ethical complexities of pregnancy – where parents and their fetuses face interconnected risks – and fears of legal liability, pregnant women are normally excluded from the randomized clinical trials that are required to obtain approval for a drug or vaccine.

In the past, it took years after vaccines were approved for general use to gather enough data to show how they work during pregnancy. Many of these subsequent studies are observational and involve fewer participants. As a result, pregnant women may hesitate to get the vaccine and doctors may postpone their recommendation.

“The result of this was decades of injustice towards pregnant women,” says Faden, who also leads the Ethics in Pregnancy Research project for Vaccines, Epidemics and New Technologies (PREVENT). Although it can sometimes make sense not to include pregnant women in the first tests, 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, sorely needed. Today, the CDC strongly encourages pregnant women to get flu shots, which are known to cause serious complications in pregnant women. Medical experts also advise vaccination against pertussis (or whooping cough), which can be fatal for newborns. Pregnant people can also receive immunizations for a handful of other illnesses, including hepatitis and meningitis.

The lessons from these vaccines have shown that there is no reason to worry about the types of vaccines that use an inactivated virus to elicit an immune response, as they cannot infect parents or the baby, says Geeta Swamy, associate professor of obstetrics and gynecology Duke University School of Medicine in North Carolina and a leading researcher on maternal immunization.

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

The Moderna and Pfizer-BioNTech vaccines for COVID-19 represent a new challenge. So far, the messenger RNA platform they use has not been licensed for human use. Thus, the only available data related to pregnancy are 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 a lot about how mRNA technology works. Instead of using inactivated or live viruses, these vaccines contain fragments of the genetic code encased in lipids, or fat globules, which protect the code from degradation. Once injected, the mRNA instructs cells to produce the SARS-CoV-2 spike protein, which activates the body’s immune response.

Theoretically, all of this is promising because, like previous vaccines, it does not involve a live virus. “Everything that is considered biologically the case for mRNA vaccines is incredibly comforting,” says Faden. “It should not have any impact on the pregnancy or the results of the pregnancy.”

Anthony Fauci, chief medical adviser to the White House, also said the data “so far do not bring any warning signs” for pregnant women.

Still, scientists have raised questions about how mRNA vaccines will actually work. The biggest concern is whether the mRNA can cross the placenta and generate the spike protein in the fetus. It wouldn’t necessarily be harmful if it did – and it wouldn’t cause birth defects – but the concern is that the fetus may 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 on 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 notes that it can be harmful to the baby when a pregnant woman has a high fever. “If this is a side effect, you would like to pay attention to this and talk to your provider about taking something to reduce the fever,” she says.

Clinical trials are underway to investigate the effects of vaccines on pregnant women. Faden would have liked these tests to have started as soon as the vaccines received FDA approval, but she points out that the process is still moving faster than in the past.

“We used to feel like one or two lonely batteries out there, beating our battery in this vast silence,” she says. “Now we have an entire percussion section asking for more data and the inclusion of pregnant women in the launch of the vaccine. And this is really good. “

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

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

But the risk of serious illness is lower for pregnant women than for other high-risk groups, such as the elderly or people with heart disease. Therefore, it is critical to look at the individual factors that increase a person’s individual risks – including the number of daily contacts, access to tests and high-quality PPE and comorbidities such as asthma or obesity – and whether there is anything that can be done to reduce them.

Time must also be taken into account. Swamy says there is no evidence that a vaccine could cause developmental problems or miscarriage in the first trimester. But women with a lower risk of infection may choose not to be vaccinated during this period, which is vital for the development of the fetal organ and is when spontaneous abortions usually occur. (The influenza vaccine is safe at any time during pregnancy.)

For pregnant women at high risk of exposure and who do not have the option to reduce that risk, it may make sense to consider getting the vaccine as soon as they are eligible. But to find out for sure, Chambers says, “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 the COVID-19 vaccines work during pregnancy. In the short term, scientists are anxiously awaiting data from pregnant health professionals who started taking vaccines in December. Faden says the data must be robust, as more than 15,000 pregnancies among those vaccinated were reported to the CDC on January 20.

In addition to mRNA vaccines, there are some new options on the horizon. Johnson & Johnson submitted its vaccine for FDA approval on February 4, while AstraZeneca and Novavax recently released critical phase three test data. All three vaccines depend on technologies that have been studied in pregnant women in the past, which, says Swamy, may provide more guarantees. (Should people get more than one type of COVID-19 vaccine?)

Recent studies have also suggested that there may be extra benefits from vaccination during pregnancy. A study published in the journal JAMA Pediatrics showed that women who were infected with COVID-19 efficiently transfer protective antibodies to their babies – especially if infected early in pregnancy. The study does not suggest that this transfer occurs after vaccination, notes co-author Karen Puopolo, a neonatologist at the Pennsylvania Hospital. But Swamy says it is good news that antibodies regularly cross the placenta in natural infections and that she hopes that vaccination will have a similar response.

“It tells us that vaccinating women could have that kind of two for the price of one,” she says, “that by vaccinating women, we are also providing some benefit during early childhood.”