By Ethan Covey

COVID-19–associated hospitalization rates of infants younger than 6 months, who are too young to be vaccinated, are high compared with other pediatric age groups and adults over 65 years of age, according to a report from the CDC.
The report, experts say, highlighted the unique risks COVID-19 poses to the youngest members of the population (MMWR Morb Mortal Wkly Rep 2022;71[45]:1442-1448).

“It’s been well recognized that older adults are at high risk of severe COVID-19 outcomes, including hospitalization,” Sarah Hamid, PhD, an epidemiologist with the CDC’s National Center for Immunization and Respiratory Diseases, told Infectious Disease Special Edition.

“At this point in the pandemic, immunity in older age groups has increased through vaccination, previous infection or both,” Dr. Hamid added. “However, infants are more likely to be immunologically naive, and vaccines are not approved for infants aged less than 6 months.”

The report focused on COVID-19–associated hospitalization rates (hospitalizations per 100,000 population) and clinical characteristics of infants under 6 months of age from June 20, 2021, through Aug. 31, 2022. The time frame included periods of predominance of the delta, omicron BA.1, omicron BA.2 and omicron BA.5 variants.

During the omicron BA.2/BA.5–predominant period, hospitalizations of infants under 6 months of age increased 11-fold, from 2.2 during the week ending on April 9 to 26.0 during the week ending on July 23, 2022, after which, rates began to decline.

Even with the notable increase in hospitalizations, indicators of the most severe disease fortunately did not rise among hospitalized infants.

Previous studies found that maternal completion of a two-dose, primary monovalent mRNA COVID-19 vaccination series during pregnancy is estimated to be 52% effective against COVID-19 hospitalization among infants younger than 6 months (N Engl J Med 2022;387:109-119). The data showcased the importance of vaccination among those who are, or plan to become, pregnant.

“Pregnant people should stay up to date with their COVID-19 vaccination to help protect themselves and infants too young to be vaccinated,” Dr. Hamid said. “If they have a COVID-19 infection, caregivers of infants should take precautions such as physical distancing, masking and frequent handwashing with soap and water.”

Dr. Hamid reported no relevant financial relationships.