In a recent report published on the United States Center for Disease Control and Prevention (US-CDC) website, researchers evaluated the durability of protection conferred by monovalent messenger ribonucleic acid (mRNA) coronavirus disease 2019 (COVID-19) vaccines against invasive mechanical ventilation (IMV) and in-hospital death during the period of the predominance of Omicron, i.e., between February 1, 2022, and January 31, 2023.
Study
In the present case-control analysis, researchers recruited immunocompetent adults aged ≥18 between February 1, 2022, and January 31, 2023, using the Investigating Respiratory Viruses in the Acutely Ill (IVY) network data to measure the VE of mRNA-based monovalent COVID-19 vaccines against COVID-19–related in-hospital death and IMV.
They collected demographic and clinical patient data through electronic health record (EHR) review, or patient/proxy interview, including IMV receipt and in-hospital death within 28 days of hospital admission.
The researchers used logistic regression to compute VE against IMV and in-hospital mortality as (1 − adjusted odds ratio [aOR]) x 100%; additionally, they compared the odds of monovalent mRNA vaccine against unvaccinated COVID-19 cases and control patients. The study model accounted for the U.S. Department of Health and Human Services region, age, gender, calendar time, and self-reported ethnicity/race.
The team stratified study results by age group, time elapsed since the last vaccine dose, and number of vaccine doses taken. They considered varying VE estimates with 95% Confidence Intervals (CIs) statistically significant. This study adhered to the CDC policy and applicable federal laws.
Results
The number of enrollees with IMV or in-hospital mortality in the IVY Network between February 1, 2022, and January 31, 2023, was 6,354; however, the final analysis sample set had only 70% of 6354, i.e., 4,421 individuals, of which 362 were cases, and 4,059 were controls. The average age of all included patients was 64 years. Notably, ~91% of COVID-19 patients had one or more persistent health issues, and 20% had experienced COVID-19 at least once.
Moreover, 146, 216, 293, and 156 of 362 COVID-19 case-patients who received IMV or suffered in-hospital death were unvaccinated, monovalent-vaccinated, received IMV, and died within 28 days of hospital admission, respectively. Of 4,059 controls, 979 (24%) and 3080 (76%) were unvaccinated and monovalent-vaccinated, respectively. Among monovalent vaccine recipients, the average time lapsed from vaccine receipt to illness onset was 248 days.
VE of two to four doses of monovalent mRNA vaccine against IMV and in-hospital mortality was 62% among adults aged ≥18 years and 57% and 69% among patients aged 18–64 years and ≥65 years, respectively. Stratifying by time since the last dose yielded VE of 76%, 54%, and 56% at seven to 179 days, 180 to 364 days, and ≥365 days, respectively.
Overall, monovalent mRNA vaccines showed a 76% efficacy in preventing COVID-19–related IMV and death up to six months after the last dose and up to 56% efficacy between one to two years. Thus, the authors recommended that all eligible adults take COVID-19 vaccines to prevent critical outcomes of COVID-19, such as IMV.
Conclusion
The current analysis reported VE for monovalent mRNA COVID-19 vaccine against IMV and in-hospital death for 12 months during the Omicron VOC era. Its results suggested that protection against IMV and death after six months from receipt of the last dose waned substantially but still remained clinically significant and offered durable immune protection for over 12 months.
In stratified subanalyses of this study, VE correlated more with time elapsed since the last dose than the number of vaccine doses received. Overall, these findings reinstate the importance of staying up to date with COVID-19 vaccination to prevent critical outcomes of COVID-19, including additional bivalent mRNA booster shots for individuals at the highest risk of progression to severe disease.
Source
https://www.news-medical.net/news/20230502/Monovalent-mRNA-COVID-19-vaccines-provide-durable-protection-against-critical-outcomes.aspx