Although COVID-19–related hospitalizations rose in the US after the SARS-CoV-2 B.1.617.2 (Delta) variant emerged this past summer, a recent analysis reported that the variant wasn’t linked with more severe disease among hospitalized patients.
Studies in Scotland and Canada have suggested that the Delta variant is associated with a higher risk of hospitalization, but it’s not certain whether the variant causes more severe disease in adults. To address that question, the CDC’s COVID-19–Associated Hospitalization Surveillance Network analyzed trends in disease severity among 7615 patients hospitalized with COVID-19 from January 1 through August 2021. The analysis found no difference in intensive care unit admissions, the need for invasive mechanical ventilation, or deaths in July and August compared with previous months when the Delta variant wasn’t the predominant strain.
However, the demographics of hospitalized patients did change. Almost three-quarters of people hospitalized during July and August were unvaccinated adults. The proportion of unvaccinated hospitalized patients aged 18 through 49 years increased from about 27% during the first 6 months of the year to about 44% in July and August. Fully vaccinated adults in this age group made up about 11% of patients hospitalized with COVID-19 during both periods.
The authors suggest that the growing share of younger hospitalized patients after the Delta variant emerged likely reflect lower vaccination rates in this age group than among older adults. As of late August, approximately 82% of US adults aged 65 years or older were fully vaccinated against SARS-CoV-2 compared with nearly 59% of those aged 18 through 64 years.
“COVID-19 vaccination is critical for all eligible adults, including those aged less than 50 years who have relatively low vaccination rates compared with older adults,” the authors wrote.