The updated COVID-19 vaccines can reduce the risk of symptomatic infection by 54% among healthy adults, according to early estimates from the CDC.
The findings are based on more than 9,000 adults who were tested for COVID at participating CVS and Walgreens pharmacies between mid-September and early January. The results are based on people who did not have an immunocompromising condition, with the CDC noting it plans to continue conducting analyses to monitor when effectiveness may wane and how well they're working to prevent severe disease.
"Everything from this study is reassuring that the vaccines are providing the protection that we expected," Ruth Link-Gelles, PhD, lead author of the study and head of the CDC's vaccine effectiveness program for COVID and respiratory syncytial virus, told CNN. "While we don’t have an estimate of vaccine effectiveness specific to immunocompromised people, the fact that the vaccine is working in the general population provides, I think, reassurance for the whole population."
The latest COVID shots became available in September and were designed to target XBB.1.5, which was the predominant strain when regulators advised vaccine makers to alter the formulas last summer. While there had been concerns as to how effective the vaccines would be against JN.1, which has since become the dominant strain in the U.S, the new CDC findings indicate they offer similar protection against it.
The study authors acknowledged a number of limitations in the report, including that vaccination status and underlying medical conditions were self-reported, leaving open the possibility of recall bias.