All three COVID-19 vaccines in use in the United States are effective at preventing hospitalisations and urgent or emergency care visits caused by the Delta variant of the coronavirus, although Moderna's shots appear to be most effective, according to national data collected in June, July and August as Delta became predominant.
Researchers with the US Centers for Disease Control and Prevention (CDC) tracked nearly 33,000 urgent care or emergency department visits and hospital admissions of adults with COVID-19-like illnesses.
Compared to people who were fully vaccinated, unvaccinated individuals were five- to seven-times more likely to test positive for the coronavirus, the researchers found.
Vaccine efficacy against urgent care or emergency department visits "was highest among Moderna vaccine recipients (92 percent), followed by Pfizer/BioNTech vaccine recipients (77 percent), and was lowest (65 percent) for Janssen (Johnson & Johnson) vaccine recipients," the researchers reported in the CDC's Morbidity and Mortality Weekly Report.
The pattern was similar for hospitalisations.
"These findings reaffirm" that all three vaccines afford "high protection" against coronavirus infections that make people sick enough to seek urgent or emergency care or be hospitalised, the CDC said.