Impact of Differential Vaccine Effectiveness on COVID-19 Hospitalization Cases: Projections for 10 Developed Countries where Booster Vaccines were Recommended

Background & ObjectivesIn a previous analysis, a decision-analytic model was used to analyze the clinical and economic impact of the differences in effectiveness between the two licensed mRNA COVID-19 booster vaccines, mRNA-1273 and BNT162b2, in 2022 for adults aged 18 years and older in the United States (US). In this analysis, the same model was used to estimate the impact that administering first booster doses with mRNA-1273 could have had on COVID-related hospitalizations and costs over a 6-month period in 10 developed countries (Australia, Canada, France, Germany, Italy, Japan, South Korea, Spain, United Kingdom [UK], and US), considering updated effectiveness data. MethodsThe model was used to estimate number of hospitalizations and related costs using the actual vaccine distribution for the first COVID-19 booster from each country. These estimates were compared to a scenario where 100% of doses for that 6-month period was assumed to be mRNA-1273. The effectiveness of mRNA-1273 compared to BNT162b2 was estimated from real world data from the UK. ResultsThe total number of doses switched to the mRNA-1273 booster would range from 4.3 million in Spain to 39.4 million in Japan. The number of hospitalizations and associated hospitalization costs would be expected to fall in all countries, with the proportional decrease ranging from 1.1% (16,800 fewer) in Germany to 8.8% (25,100 fewer) in Australia. ConclusionsReal-world effectiveness data suggest that a booster dose of the mRNA-1273 vaccine may be more effective compared to other vaccines used for booster doses. Given this difference in effectiveness, results of this analysis demonstrate that switching to 100% mRNA-1273 boosters would have reduced the number of hospitalizations and associated costs in each country during the first 6 months of the omicron period.