ANN ARBOR, Mich. – New research out of the University of Michigan sheds light on the effectiveness of COVID-19 vaccine boosters in preventing severe outcomes and highlights the importance of annual vaccine updates. The study, conducted by a team of researchers, analyzed over 80 studies and 150 million patient observations to evaluate the benefits of monovalent and bivalent COVID-19 boosters in preventing hospitalization and death.
The researchers delved into the various vaccine regimens, including monovalent boosters targeting the original strain, second monovalent boosters with the original formulation, and the new bivalent vaccine updated to target newer Omicron variants. They found that all sequential doses provided a substantial benefit in preventing hospitalization and death, with the most significant estimates coming from the fall 2022 Omicron-specific vaccine dose.
The findings support the practice of periodically updating COVID-19 vaccines to match currently circulating variants, and the researchers anticipate that the conclusions on the utility of updating vaccines should apply to any future annual vaccine formulations. However, they stress the need for additional monitoring and study of the real-world effectiveness of annual vaccines.
Biostatistics and epidemiology played a significant role in the research, providing a toolbox for the complex process of evaluating vaccine effectiveness in scientific observational studies. The researchers found that vaccine effectiveness estimates remain stable and do not heavily depend on the choice of methods for the outcomes of hospitalization and mortality.
The results of the study convey a crucial message to the public regarding the power of COVID-19 boosters in preventing severe illness and hospitalization. The fall 2022 bivalent vaccine, along with other COVID-19 vaccines examined in the study, provided strong protection against hospitalization and death. However, continued study of future vaccines is warranted, and the findings provide important points of consideration for these upcoming studies.
The full study, titled “Design and analysis heterogeneity in observational studies of COVID-19 booster effectiveness: A review and case study,” was published in Science Advances. The study was a part of the School of Public Health’s IDEAS initiative, promoting interdisciplinary collaboration among researchers.