Study: 75% of infants hospitalized with COVID-19 born to unvaccinated women



This week, studies in Morbidity and Mortality Weekly Report describe the landscape of COVID-19 vaccination among women of reproductive age and those who are pregnant, showing better outcomes for infants whose mothers were vaccinated during pregnancy.

Maternal mRNA vaccines against COVID-19 have been widely recommended by providers for more than 2 years, and now evidence from the Omicron surge shows they were effective in preventing hospitalizations for infants ages 6 months or less.

Currently, babies 6 months and older can get vaccinated.

VE of 54% for babies under 3 months

A case-control study conducted from March 9, 2022, to May 31, 2023, evaluated the vaccine effectiveness (VE) of maternal receipt of a COVID-19 vaccine dose during pregnancy for infants under 6 months of age and a group of infants under 3 months. A total of 716 hospitalized infants (377 case-patients and 339 control patients) were included in the final study, and the median age was 2.3 months.

Of the 377 case-patients, 82 (22%) were born to mothers who had received a COVID-19 vaccine dose during pregnancy, compared with 94 (28%) born to mothers of control patients. Fifty babies in the study required life support, and mothers of 42 of those 50 were unvaccinated.

VE of maternal vaccination during pregnancy against COVID-19–related hospitalization was 35% (95% confidence interval [CI], 15% to 51%) among infants aged less than 6 months and 54% (95% CI , 2% to 68%) among infants aged less than 3 months.

Invasive mechanical ventilation was more common among infants of unvaccinated (9%) than vaccinated mothers (1%), the authors said.

"These findings indicate that maternal vaccination during pregnancy could help prevent COVID-19–related hospitalization in infants too young to be vaccinated, particularly during the first 3 months of life," the authors wrote. "Expectant mothers should be counseled to remain current with COVID-19 vaccination to protect themselves and their infants from hospitalization and severe outcomes associated with COVID-19."

Only 54.7% of HCPs offered vaccines to women

In another study published in MMWR, authors used answers from the fall 2022 DocStyles survey to see which type of healthcare providers (HCPs) recommended and administered COVID-19 vaccines to women of reproductive age.

Though 83% of those surveyed said they recommended the vaccine to women of reproductive age, only 54.7% administered the vaccine in their practice.

Provider recommendation for vaccination is strongly associated with patient acceptance of vaccine and with vaccination coverage.

Obstetrician-gynecologists were more likely to recommend COVID-19 vaccination to pregnant patients (94.2%) than were family practitioners or internists (82.1%) (adjusted prevalence ratio, 1.1).

"Provider recommendation for vaccination is strongly associated with patient acceptance of vaccine and with vaccination coverage," the authors concluded. "Encouraging HCPs to recommend, offer, and administer COVID-19 vaccines, along with influenza or tetanus, diphtheria, pertussis (Tdap) vaccines, might help reinforce vaccine confidence and increase vaccination coverage among women of reproductive age, including pregnant women.”

Another recent study in MMWR shows that during the 2022-2023 influenza season, 47.2% of women were vaccinated against influenza before or during pregnancy, 55.4% of women with a recent live birth received Tdap vaccination during pregnancy, and 27.3% of women received a COVID-19 bivalent (two-strain) booster vaccine before or during pregnancy.

That study was based on survey responses from 1,814 women who were pregnant at any time during October 2022 through January 2023.

Influenza vaccine uptake among pregnant women in the 2022-2023 flu season was 10 percentage points lower than during the 2019-2020 flu season.

"Maternal vaccination coverage remains suboptimal," the authors concluded. "Culturally relevant vaccination recommendations from health care providers are critical to improving vaccination coverage, decreasing persistent disparities in vaccination coverage, combatting increases in vaccine hesitancy observed since the start of the COVID-19 pandemic."

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