Cost-effectiveness of the second COVID-19 booster vaccination in the United States

Background The United States (US) authorized the second COVID-19 booster for individuals aged 50+ years on March 29, 2022. To date, the cost-effectiveness of the second booster strategy remains unassessed. Methods We developed a decision-analytic SEIR-Markov model by five age groups (0-4yrs, 5-11yrs 12-17yrs, 18-49yrs, and 50+yrs) and calibrated the model by actual mortality in each age group in the US. We conducted fives scenarios to evaluate the cost-effectiveness of the second booster strategy and incremental benefits if the strategy would expand to 18-49yrs and 12-17yrs, from a healthcare system perspective. Findings Implementing the second booster strategy for those aged 50+yrs would cost $807 million but reduce direct medical costs by $1,128 million, corresponding to a benefit-cost ratio of 1.40. Moreover, the strategy would also result in a gain of 1,048 quality-adjusted life-years (QALYs) during the 180 days, indicating it was cost-saving. Further, vaccinating individuals aged 18-49yrs with the second booster would result in an additional gain of $1,566 million and 2,276 QALYs. Similarly, expanding vaccination to individuals aged 12-17yrs would result in an additional gain of $15 million and 89 QALYs. However, if social interaction between all age groups was severed, vaccination expansion to 18-49yrs and 12-17yrs would no longer be cost-effective. Interpretation The second booster strategy was likely to be cost-effective in reducing the disease burden of the COVID-19 pandemic. Expanding the second booster strategy to 18-49yrs and 12-17yrs would remain cost-effective due to their social contacts with the older age group. Funding World Health Organization ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement LZ is supported by the National Natural Science Foundation of China (Grant number: 81950410639), Outstanding Young Scholars Funding (Grant number: 3111500001), Xi'an Jiaotong University Basic Research and Profession Grant (Grant number: xtr022019003 and xzy032020032), and Xi'an Jiaotong University Young Talent Support Grant (Grant number: YX6J004). We are grateful to Kiyohiko Izumi for his skilful review of the published work. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript