The original COVID-19 mRNA vaccines provided durable protection against the need for invasive mechanical ventilation and in-hospital death during the pandemic’s omicron period, a new federal study has found.
The study, lead by Jennifer DeCuir, MD, PhD, of the National Center for Immunization and Respiratory Diseases, aimed to determine durability of the vaccines against these two outcomes.
69% protection for seniors
The researchers analyzed data from immunocompetent adults admitted to 24 hospitals in 19 U.S. states. Results revealed that those who received 2 to 4 monovalent mRNA COVID-19 vaccine doses derived 62% protection overall against the need for COVID-19–associated invasive mechanical ventilation.
In addition, adults in the 65 years and older age group received 69% protection, the authors reported.
The most significant protection was seen in the first six months after the patients’ last monovalent doses, with ongoing efficacy sustained at 1 to 2 years, DeCuir and colleagues reported. When vaccine efficacy (VE) was categorized by time since last dose, they found VE was 76% at 7 to 179 days; 54% at 180 to 364 days; and 56% at 365 days or later.
Time since last dose is key
Since the beginning of the pandemic, approximately 1.1 million deaths have been attributed to COVID-19, with most occurring among patients aged 65 years and older, the researchers reported. According to the new study findings, protection against critical outcomes appears to correlate more closely with time since the last vaccine dose than with the total number of doses received, they reported.
To date, only 42% U.S. seniors have received a bivalent mRNA COVID-19 vaccine dose and are up to date with their COVID-19 vaccinations, the authors added.
The CDC recommends that all adults remain current with their COVID-19 vaccinations, including the updated bivalent vaccine, to prevent critical outcomes, they concluded in the CDC’s Morbidity and Mortality Weekly Report.
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