PIN153 Lessons Learned from Economic Models of Influenza Vaccines and Applications to SARS-CoV-2

Benner, J.; Adair, N.; Friedman, M.; Menzin, J.; Sussman, M.

Objectives: The SARS-CoV-2 pandemic has had unprecedented clinical and economic effects worldwide, with global efforts to develop a protective vaccine. Mass vaccination strategies have been employed to reduce seasonal influenza outbreaks. We identified published economic models assessing influenza vaccination strategies to determine which key economic modeling components could be useful for future models in support of a SARS-CoV-2 vaccine. Methods: Economic models published between January 2009 and June 2020 were identified by searching Medline (through National Library of Medicine’s PubMed) and GoogleScholar. The search strategy combined terminology for influenza vaccines with terminology for economic models (e.g., cost-effectiveness, cost-benefit, cost-consequence, decision trees, Markov). Results: 1,154 records were screened for inclusion;21 publications were included in the analysis. Sixteen identified models employed a Markov cohort or patient-level simulation approach, while 18 models incorporated quality-of-life and 13 incorporated a societal perspective;typical health states included uninfected, incubating, asymptomatic, symptomatic+isolated, symptomatic+circulating, partially immune, and dead. Common clinical outcomes included avoidance of virus cases, hospitalizations, and deaths;economic outcomes included cost savings associated with reduced hospitalizations, increased quality-of-life, and productivity gains. All but 1 model considered transmission rate, vaccination rate, vaccine efficacy, and rate of complications as key model drivers, whereas only 3 models considered vaccination plus broader public health strategies. Only 7 models incorporated herd immunity, citing uncertainty around availability and efficacy. While all models considered age and risk stratifications, no models assessed the implications of vaccination across different racial and ethnic groups. Conclusions: Future economic modeling in support of a SARS-CoV-2 vaccine should incorporate the components of existing model frameworks for influenza vaccination strategies as well as account for differences specific to SAR-CoV-2 including broader public health strategies (e.g., face masks, social distancing) and racial disparities. Without these elements, future models may fail to accurately capture the potential benefits of a SARS-CoV-2 vaccine.