Evaluation of COVID-19 vaccination strategies with a delayed second dose
- DOI
- Language of the publication
- English
- Date
- 2021-04-21
- Type
- Article
- Author(s)
- Moghadas, Seyed M.
- Vilches, Thomas N.
- Zhang, Kevin
- Nourbakhsh, Shokoofeh
- Sah, Pratha
- Fitzpatrick, Meagan C.
- Galvani, Alison P.
- Publisher
- PLOS Biology
Abstract
Two of the Coronavirus Disease 2019 (COVID-19) vaccines currently approved in the United States require 2 doses, administered 3 to 4 weeks apart. Constraints in vaccine supply and distribution capacity, together with a deadly wave of COVID-19 from November 2020 to January 2021 and the emergence of highly contagious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants, sparked a policy debate on whether to vaccinate more individuals with the first dose of available vaccines and delay the second dose or to continue with the recommended 2-dose series as tested in clinical trials. We developed an agent-based model of COVID-19 transmission to compare the impact of these 2 vaccination strategies, while varying the temporal waning of vaccine efficacy following the first dose and the level of preexisting immunity in the population. Our results show that for Moderna vaccines, a delay of at least 9 weeks could maximize vaccination program effectiveness and avert at least an additional 17.3 (95% credible interval [CrI]: 7.8–29.7) infections, 0.69 (95% CrI: 0.52–0.97) hospitalizations, and 0.34 (95% CrI: 0.25–0.44) deaths per 10,000 population compared to the recommended 4-week interval between the 2 doses. Pfizer-BioNTech vaccines also averted an additional 0.60 (95% CrI: 0.37–0.89) hospitalizations and 0.32 (95% CrI: 0.23–0.45) deaths per 10,000 population in a 9-week delayed second dose (DSD) strategy compared to the 3-week recommended schedule between doses. However, there was no clear advantage of delaying the second dose with Pfizer-BioNTech vaccines in reducing infections, unless the efficacy of the first dose did not wane over time. Our findings underscore the importance of quantifying the characteristics and durability of vaccine-induced protection after the first dose in order to determine the optimal time interval between the 2 doses.
Plain language summary
Two of the Coronavirus Disease 2019 (COVID-19) vaccines currently approved in the United States require 2 doses, administered 3 to 4 weeks apart. Constraints in vaccine supply and distribution capacity, together with a deadly wave of COVID-19 from November 2020 to January 2021 and the emergence of highly contagious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants, sparked a policy debate on whether to vaccinate more individuals with the first dose of available vaccines and delay the second dose or to continue with the recommended 2-dose series as tested in clinical trials. We developed an agent-based model of COVID-19 transmission to compare the impact of these 2 vaccination strategies. Our results show that for Moderna vaccines, a delay of at least 9 weeks could avert at least an additional 17.3 infections, 0.69 hospitalizations, and 0.34 deaths per 10,000 population compared to the recommended 4-week interval. Pfizer-BioNTech vaccines also averted an additional 0.60 hospitalizations and 0.32 deaths per 10,000 population in a 9-week delayed second dose. However, there was no clear advantage of delaying the second dose with Pfizer-BioNTech vaccines in reducing infections, unless the efficacy of the first dose did not wane over time.
Subject
- Health
Keywords
- COVID-19 / epidemiology,
- COVID-19 / immunology actions Search in PubMed Search in MeSH Add to Search,
- COVID-19 / prevention & control*,
- COVID-19 Vaccines / administration & dosage*,
- COVID-19 Vaccines / supply & distribution,
- Hospitalization / statistics & numerical data,
- Humans,
- Immunization Schedule,
- Immunization, Secondary,
- Models, Statistical,
- Mortality,
- SARS-CoV-2 / immunology*,
- United States / epidemiology,
- Vaccination / methods*,
- Vaccination / statistics & numerical data
Rights
Peer review
Yes
Open access level
Gold
Identifiers
- PubMed ID
- 33882066
Article
- Journal title
- PLOS Biology
- Journal volume
- 19
- Journal issue
- 7
- Article number
- e3001211
Citation(s)
Moghadas SM, Vilches TN, Zhang K, Nourbakhsh S, Sah P, Fitzpatrick MC, et al. (2021) Evaluation of COVID-19 vaccination strategies with a delayed second dose. PLoS Biol 19(4): e3001211. https://doi.org/10.1371/journal.pbio.3001211