Optimized delay of the second COVID-19 vaccine dose reduces ICU admissions

Author(s)

Silva, Paulo J. S. ^[1] ; Sagastizabal, Claudia ^[1] ; Nonato, Luis Gustavo ^[2] ; Struchiner, Claudio Jose ^[3] ; Pereira, Tiago ^[2]

Affiliation

^[1] Univ Estadual Campinas, Inst Matemat Estat & Comp Cient, BR-13083859 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Ciencias Matemat & Comp, BR-13566590 Sao Paulo - Brazil

^[3] Fundaco Getulio Vargas, Escola Matemat Aplicada, BR-222509 Rio De Janeiro - Brazil

• Document type: Journal article
• Source: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA; v. 118, n. 35 AUG 25 2021.
• Web of Science Citations: 1

Abstract

Slower than anticipated, COVID-19 vaccine production and distribution have impaired efforts to curtail the current pandemic. The standard administration schedule for most COVID-19 vaccines currently approved is two doses administered 3 to 4 wk apart. To increase the number of individuals with partial protection, some governments are considering delaying the second vaccine dose. However, the delay duration must take into account crucial factors, such as the degree of protection conferred by a single dose, the anticipated vaccine supply pipeline, and the potential emergence of more virulent COVID-19 variants. To help guide decision-making, we propose here an optimization model based on extended susceptible, exposed, infectious, and removed (SEIR) dynamics that determines the optimal delay duration between the first and second COVID-19 vaccine doses. The model assumes lenient social distancing and uses intensive care unit (ICU) admission as a key metric while selecting the optimal duration between doses vs. the standard 4-wk delay. While epistemic uncertainties apply to the interpretation of simulation outputs, we found that the delay is dependent on the vaccine mechanism of action and first-dose efficacy. For infection-blocking vaccines with firstdose efficacy >50%, the model predicts that the second dose can be delayed by >8 wk (half of the maximal delay), whereas for symptom-alleviating vaccines, the same delay is recommended only if the first-dose efficacy is >70%. Our model predicts that a 12-wk second-dose delay of an infection-blocking vaccine with a first-dose efficacy >70% could reduce ICU admissions by 400 people per million over 200 d. (AU)

• FAPESP's process: 13/07375-0 - CeMEAI - Center for Mathematical Sciences Applied to Industry
• Grantee: Francisco Louzada Neto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 18/24293-0 - Computational methods in optimization
• Grantee: Sandra Augusta Santos
• Support Opportunities: Research Projects - Thematic Grants