Evaluation of COVID-19 vaccination strategies with a delayed second dose

Thumbnail image

Download files

DOI

https://doi.org/10.1371/journal.pbio.3001211

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

Creative Commons Attribution 4.0 International (CC BY 4.0)

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

Download(s)

URI

Collection(s)

Communicable diseases

Full item page

Full item page

Page details

Date modified: