Risk of neonatal RDS (respiratory distress syndrome) is 3.06 times greater for full-term neonates exposed to SARS-CoV-2 in utero if their mothers were not vaccinated prior to infection, according to research published in Nature Communications.1

In the study, researchers at David Geffen School of Medicine at UCLA examined the relationship between maternal COVID-19 vaccination and neonatal RDS. To do so, they conducted a longitudinal study of 221 mothers with laboratory-confirmed COVID-19 and 199 SARS-CoV-exposed infants until 6-months of age.

Study by the Numbers1

Researchers reported unusually high rates of neonatal RDS in SARS-CoV-2 exposed uninfected (SEU) infants (34 of 199, or 17% of infants in the study).

  • The study enrolled 221 mothers with laboratory-confirmed COVID-19.
    • Sixty-eight percent (n = 151) were unvaccinated
      • 16% of these unvaccinated mothers (n = 23) had severe or critical disease present.
      • By comparison, 4% of vaccinated mothers (n = 3) had severe or critical disease.
        • The prevalence of severe or critical COVID-19 in mothers was significantly higher among infants with RD compared to those without RD (21% vs 6%), respectively.
  • The study followed 199 SARS-CoV-exposed infants until 6-months of age
    • 0% of infants tested positive for SARS-CoV-2 at birth
    • 17% (n=34) were diagnosed with respiratory distress
      • 15% of infants with RD were born to mothers vaccinated prior to SARS-CoV-2 infection
      • 85% of infants with RD were born to mothers not vaccinated prior to SARS-CoV-2 infection
      • 13 infants with RD were full-term (38.2%)
      • 23 infants had a low birth weight (68%)

According to data, 85% of infants with respiratory distress were born to mothers not vaccinated prior to SARS-CoV-2 infection (compared to 15% born to vaccinated mothers). In addition, prevalence of severe or critical COVID-19 in mothers was significantly higher among infants with RD compared to those without RD (21% vs 6%, respectively).1

“Not only do our results show higher rates of [respiratory distress] in [SARS-CoV-2 exposed uninfected] infants when compared to the general population,” the researchers write, “but we observed more cases of RD at later gestational ages than anticipated, when neonates should presumably have more mature lung anatomy.”

Researchers concluded that the odds of neonatal respiratory distress were significantly reduced among full-term infants if mothers received at least one mRNA COVID-19 vaccine prior to infection.

“Moreover, our study highlights the importance of public health interventions and vaccination efforts that target pregnant individuals due to the potential for lasting effects on the health of both the mother and the infant,” the authors wrote, while also acknowledging that the small sample size of the study warrants further research and caution in interpreting current results.1


Reference

  1. Man O, et al. Respiratory distress in SARS-CoV-2 exposed uninfected neonates followed in the COVID Outcomes in Mother-Infant Pairs (COMP) Study. 2024. Nature Communications, 15:399. https://www.nature.com/articles/s41467-023-44549-5

sars-cov-2 rds