COVID-19 vaccines prove safe for pregnant women, yet hesitancy remains high

When the COVID-19 vaccines first hit the market, there was little to no vaccine safety data for pregnant women. That’s because the manufacturers didn’t test the vaccines on this population, a move that spoke to a long-lived trend in America's healthcare system in which pregnant women are actively excluded from the clinical vaccine trials and critical research in healthcare.

At the time, experts told Salon that the move blatantly failed to protect pregnant women, especially those who were frontline workers. It also fueled vaccine hesitancy, which was already a problem within the pregnant and non-pregnant community. 

But since then, multiple studies including hundreds of thousands of people have effectively demonstrated that the COVID-19 vaccines are safe for pregnant women both before and after pregnancy. In contrast, COVID-19 infection during pregnancy appears to be much more dangerous. Several studies have found that those who have COVID-19 during pregnancy are more likely to be at risk of preterm birth, stillbirth, preeclampsia and other pregnancy complications.

This week, a new study published in the journal Nature Communications found that infants born full-term to mothers who were infected with COVID-19 during pregnancy were three times more likely to have trouble breathing immediately after birth compared to infants whose mothers weren't infected with the virus. The study had 221 mothers who were enrolled; 68 percent of which were unvaccinated prior to their COVID-19 infection. Of the 34 infants who were born with respiratory issues, only 5 were born to mothers who had been vaccinated — indicating that COVID-19 vaccines have a protective effect.

“Babies who had been born to mothers who had received at least one dose of the COVID vaccine in pregnancy before they got sick, actually had no respiratory distress,” senior author Dr. Karin Nielsen, a professor of pediatrics in the division of pediatric infectious diseases at University of California-Los Angeles, told Salon. “There was a three-chance higher risk of having respiratory distress for the babies born to unimmunized mothers.” 

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The study went beyond identifying this association and dug deeper into the potential mechanism as to why this could be happening. Importantly, the infants who had respiratory distress weren’t infected with COVID-19 themselves, but something was going on that made it difficult for them to breathe. Nielsen and her colleagues proceeded to do a molecular analysis called proteomics which looks at markers of inflammation in the blood. They found that the infants who experienced respiratory distress had malfunctioning cilia in their airways, which refers to the hair-like structures that cleanse the airways of inhaled particles and pathogens.

“Babies that had the respiratory distress, at least at the molecular level, it seemed that the cilia weren't functioning very well,” she said. “They also had much higher inflammation in their blood markers, and they also had higher IgE levels, an immunoglobulin associated with reactive airway disease, asthma and other breathing problems.”

Nielsen said that the inflammation caused by COVID-19 leads to an inflammatory response in the infants as well. 

“It’s not like the inflammation of the mother crosses the placenta and reaches the baby, those proteins in the mother's blood don't cross the placenta, but the baby develops an inflammatory response of their own developing in the womb in the presence of ongoing inflammation,” she said. “It’s important because this is a serious condition, a newborn that can't breathe is a life-threatening condition.”

The COVID-19 vaccine doesn’t entirely protect against infection, but it decreases the likelihood of someone having a severe case of the SARS-CoV-2 virus responsible. Long COVID, a condition in which the symptoms of COVID last for months or never resolve, is uncommon in infants, but it does happen and it can be very debilitating in children. The symptoms can also look different from adults, according to the National Institutes of Health.

A study published this month in The Lancet reported "Vaccination against COVID-19 consistently reduced the risk of long COVID symptoms." The American College of Obstetricians and Gynecologists strongly recommends COVID vaccines for pregnant individuals, no matter what trimester. Unfortunately, only about 1 in 5 people over age 18 have gotten the latest COVID vaccines, according to data from the Centers for Disease Control and Prevention.

The way the vaccines help, according to Nielsen, is it primes the immune system by potentially reducing the inflammatory response, which could be why it helps decrease the chances of an infant being born with breathing issues. Nielsen said the potential impact can extend beyond the first few days of an infant’s life, too.In fact, the researchers are looking ahead to doing another analysis to see if these infants have breathing issues or asthma. 

“They could have problems later in terms of more recurrent respiratory infections” she said.  “This could trigger more reactive airway disease or even damage to the lung tissue, so we are going to look at that.”