A new study by Centers for Disease Control and Prevention researchers found no obvious safety concerns in some 35,000 pregnant people who were vaccinated, including in the third trimester.

A new study by Centers for Disease Control and Prevention researchers found no obvious safety concerns in some 35,000 pregnant people who were vaccinated, including in the third trimester. / San Francisco Chronicle via Getty Images

The Centers for Disease Control and Prevention "recommends that pregnant people receive the COVID-19 vaccine," CDC Director Rochelle Walensky said Friday, citing a new study on the Moderna and Pfizer-BioNTech vaccines.

Early clinical trials of the two-dose shots did not include pregnant individuals, limiting data and creating a sense of uncertainty for many.

COVID-19 vaccines made by Moderna and Pfizer-BioNTech appear to be safe for people who are pregnant, according to new research from the CDC.

Preliminary findings published this week in The New England Journal of Medicine evaluated data from more than 35,000 pregnant individuals who received the mRNA vaccines, and found no obvious safety concerns.

"Importantly, no safety concerns were observed for people vaccinated in the third trimester, or safety concerns for their babies," Walensky said at a Friday briefing. "As such, CDC recommends that pregnant people receive the COVID-19 vaccine."

The CDC, American College of Obstetricians and Gynecologists and American Academy of Pediatrics have all previously issued guidance "indicating that COVID-19 vaccines should not be withheld from pregnant persons," as the study noted.

Researchers looked at data between Dec. 14 and Feb. 28 from three federal databases and registries through which vaccine recipients nationwide can report side effects and provide information about their health.

Pregnant individuals reported pain at the injection site more frequently than their nonpregnant counterparts but fewer follow-up symptoms such as headache, chills, muscle pain and fever.

Researchers said that the rates of preterm births and miscarriages among the vaccinated people who completed their pregnancies during the study period were similar to those of the general pregnant population.

"Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA Covid-19 vaccines," they wrote. "However, more longitudinal follow-up, including follow-up of large numbers of women vaccinated earlier in pregnancy, is necessary to inform maternal, pregnancy, and infant outcomes."

This study did not look at the Johnson & Johnson vaccine, which was first authorized for use in the U.S. in late February.

Another study published last month found that the Pfizer and Moderna vaccines were safe and effective for pregnant and nursing individuals, and may even offer some protection to their babies. Like this week's study, it noted that people who are pregnant face a higher risk of severe disease and death from COVID-19 than those who are not, though it remains low overall.

The CDC's Walensky acknowledged the decision to get vaccinated while pregnant is a "deeply personal" one and encouraged those who are deliberating to talk to their doctors or primary care providers.

She also highlighted what she described as the latest victories and concerns in the country's effort to vaccinate its way out of the pandemic.

There has been a 10% drop in the seven-day average of new reported cases, with the latest figure showing 62,500 cases per day. The number of daily confirmed deaths is declining but still hovering around 690 per day.

More than 65% of the U.S. population ages 65 and older is fully vaccinated as of Friday, which Walensky called "a reason to celebrate." But she also urged caution, noting that county-level data reveals "unsettling gaps" in the pace of vaccinations.

Some counties have vaccinated more than 65% of their elderly population, while other areas remain below 50%, she said.

"Because this virus is an opportunist, we anticipate that the areas of lightest vaccine coverage now might be where the virus strikes next, and with modest protection for our oldest population, many more deaths could ensue," Walensky warned. "So while we have many reasons to celebrate, we also have the potential — indeed the need — to do more to protect people now."

Nearly 27% of the U.S. population has been fully vaccinated as of Friday, according to NPR's vaccine tracker.

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Tags: COVID-19 vaccine  Centers for Disease Control and Prevention  pregnancy  Series: The Coronavirus Crisis