moderna vaccine
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A preprint study posted late last week on the server medRxiv reveals that the current Moderna COVID-19 vaccine is 53% effective against COVID-19–related hospitalization and 39% protective against medically attended COVID-19 over a median follow-up period of 57 days.
The study, which has not yet been peer-reviewed, evaluated the effectiveness of Moderna's updated vaccine targeting the KP.2 variant at preventing hospitalizations and medically attended COVID-19 illness. Outcomes among recipients of the vaccine were compared to people who did not receive any 2024-25 COVID vaccine.
The retrospective matched cohort study used electronic health records to determine vaccinations from August 23, 2024, through December 24, 2024, and with follow-up through December 31, 2024. Overall, 465,073 KP.2 vaccine recipients were matched 1:1 to unexposed adults.
70% had underlying medical conditions
The average age of participants was 63 years, with more than half being 65 years or older. Seventy percent of people in the study had an underlying medical condition that made them high risk for severe COVID-19 outcomes.
The most common underlying medical conditions were obesity (exposed, 25.3%; unexposed, 26.5%), diabetes mellitus (21.7% and 23.5%, respectively), and heart conditions (17.9% and 19.7%, respectively).
"Most patients (73%) in the study population had documentation of a previous vaccination for COVID-19," the authors said.
Lower protection in those with underlying conditions
Vaccine effectiveness (VE) was 52.8% (95% confidence interval [CI], 34.8% to 65.8%) against COVID-19–related hospitalization, and 39.4% (95% CI; 35.0% to 43.5%) against medically attended COVID-19 over a median follow-up of 57 days.
Adjusted VE against COVID-19–related hospitalization was 53.1% for adults 50 years old or older, 53.2% among adults 65 years old or older, and 46.5% among adults with at least one underlying medical condition. Adjusted VE against medically attended COVID-19 was 41.2% for adults ages 50 years old and older, 46.7% among those 65 years old or older, and 40.4% among adults with at least one underlying medical condition.
"Most individuals in the study (over 70%) previously received a 2023-2024 mRNA-1273 [Moderna] vaccine targeting the XBB.1.5 variant. Thus, the results of this study should be interpreted in the context of the incremental protection against hospitalization provided by the most updated COVID-19 against the circulating variants in a real-world setting regardless of exposure and/or vaccination history," the authors said.