Investigating the Marginal and Herd Effects of COVID-19 Vaccination for Reducing Case Fatality Rate: Evidence from the United States between March 2021 to January 2022
Author:
Li Tenglong1ORCID, Wang Zilong2ORCID, He Shuyue1, Chen Ying1ORCID
Affiliation:
1. Wisdom Lake Academy of Pharmacy, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China 2. Department of Financial and Actuarial Mathematics, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China
Abstract
Vaccination campaigns have been rolled out in most countries to increase vaccination coverage and protect against case mortality during the ongoing pandemic. To evaluate the effectiveness of COVID-19 vaccination, it is vital to disentangle the herd effect from the marginal effect and parameterize them separately in a model. To demonstrate this, we study the relationship between the COVID-19 vaccination coverage and case fatality rate (CFR) based on U.S. vaccination coverage at county level, with daily records from 11 March 2021 to 26 January 2022 for 3109 U.S. counties. Using segmented regression, we discovered three breakpoints of the vaccination coverage, at which herd effects could potentially exist. Controlling for county heterogeneity, we found the size of the marginal effect was not constant but actually increased as the vaccination coverage increased, and only the herd effect at the first breakpoint to be statistically significant, which implied an indirect benefit of vaccination may exist at the early stage of a vaccination campaign. Our results demonstrated that public-health researchers should carefully differentiate and quantify the herd and marginal effects when analyzing vaccination data, to better inform vaccination-campaign strategies as well as evaluate vaccination effectiveness.
Subject
Pharmacology (medical),Infectious Diseases,Drug Discovery,Pharmacology,Immunology
Reference48 articles.
1. Capalbo, C., Aceti, A., Simmaco, M., Bonfini, R., Rocco, M., Ricci, A., Napoli, C., Rocco, M., Alfonsi, V., and Teggi, A. (2020). The exponential phase of the COVID-19 pandemic in central Italy: An Integrated Care Pathway. Int. J. Environ. Res. Public Health, 17. 2. Ongoing and future COVID-19 vaccine clinical trials: Challenges and opportunities;Bekker;Lancet Infect. Dis.,2021 3. Yan, Z.P., Yang, M., and Lai, C.L. (2021). COVID-19 vaccines: A review of the safety and efficacy of current clinical trials. Pharmaceuticals, 14. 4. Ahmed, S., Khan, S., Imran, I., Al Mughairbi, F., Sheikh, F.S., Hussain, J., Khan, A., and Al-Harrasi, A. (2021). Vaccine development against COVID-19: Study from pre-clinical phases to clinical trials and global use. Vaccines, 9. 5. World Health Organization (2022, November 24). Global COVID-19 Vaccination Strategy in a Changing World. Available online: https://www.who.int/publications/m/item/global-covid-19-vaccination-strategy-in-a-changing-world--july-2022-update.
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