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Modelling optimal vaccination strategies against COVID-19 in a context of Gamma variant predominance in Brazil.
Ferreira, Leonardo Souto; de Almeida, Gabriel Berg; Borges, Marcelo Eduardo; Simon, Lorena Mendes; Poloni, Silas; Bagattini, Ângela Maria; da Rosa, Michelle Quarti Machado; Diniz Filho, José Alexandre Felizola; Kuchenbecker, Ricardo de Souza; Camey, Suzi Alves; Kraenkel, Roberto André; Coutinho, Renato Mendes; Toscano, Cristiana Maria.
  • Ferreira LS; São Paulo State University (UNESP), Institute for Theoretical Physics (IFT) - R. Dr. Bento Teobaldo Ferraz, 271 - Bloco II - Barra-Funda - São Paulo/SP - CEP 01140-070, Brazil; Observatório COVID-19 BR - São Paulo/SP, Brazil. Electronic address: leonardo.souto@unesp.br.
  • de Almeida GB; São Paulo State University (UNESP), Infectious Diseases Department, Botucatu Medical School (FMB) - Av. Prof. Mário Rubens Guimarães Montenegro, s/n - Botucatu/SP - CEP 18618-687, Brazil.
  • Borges ME; Observatório COVID-19 BR - São Paulo/SP, Brazil; Federal University of ABC (UFABC), Center for Mathematics, Computation and Cognition - Avenida dos Estados, 5001 - Bairro Bangu - Santo André/SP - CEP 09210-580, Brazil.
  • Simon LM; Federal University of Goiás (UFG), Department of Ecology, Postgraduate Programme in Ecology and Evolution - Av. Esperança, s/n - Chácaras de Recreio Samambaia - Goiânia/GO - CEP 74690-900, Brazil.
  • Poloni S; São Paulo State University (UNESP), Institute for Theoretical Physics (IFT) - R. Dr. Bento Teobaldo Ferraz, 271 - Bloco II - Barra-Funda - São Paulo/SP - CEP 01140-070, Brazil; Observatório COVID-19 BR - São Paulo/SP, Brazil.
  • Bagattini ÂM; Federal University of Goiás (UFG), Institute of Tropical Pathology and Public Health (IPTSP) - R. 235, s/n - Setor Leste Universitário - Goiânia/GO - CEP 74605-050, Brazil.
  • da Rosa MQM; Federal University of Goiás (UFG), Institute of Tropical Pathology and Public Health (IPTSP) - R. 235, s/n - Setor Leste Universitário - Goiânia/GO - CEP 74605-050, Brazil.
  • Diniz Filho JAF; Observatório COVID-19 BR - São Paulo/SP, Brazil; Federal University of Goiás (UFG), Department of Ecology, Postgraduate Programme in Ecology and Evolution - Av. Esperança, s/n - Chácaras de Recreio Samambaia - Goiânia/GO - CEP 74690-900, Brazil.
  • Kuchenbecker RS; Federal University of Rio Grande do Sul (UFRGS), Postgraduate Programme of Epidemiology, Medical School - Campus Saúde - R. Ramiro Barcelos, 2400 - Porto Alegre/RS - CEP 90035-003, Brazil.
  • Camey SA; Federal University of Rio Grande do Sul (UFRGS), Institute of Mathematics and Statistics, Department of Statistics - Av. Bento Gonçalves, 9500 - Agronomia - Porto Alegre/RS - CEP 91509-900, Brazil.
  • Kraenkel RA; São Paulo State University (UNESP), Institute for Theoretical Physics (IFT) - R. Dr. Bento Teobaldo Ferraz, 271 - Bloco II - Barra-Funda - São Paulo/SP - CEP 01140-070, Brazil; Observatório COVID-19 BR - São Paulo/SP, Brazil.
  • Coutinho RM; Observatório COVID-19 BR - São Paulo/SP, Brazil; Federal University of ABC (UFABC), Center for Mathematics, Computation and Cognition - Avenida dos Estados, 5001 - Bairro Bangu - Santo André/SP - CEP 09210-580, Brazil.
  • Toscano CM; Federal University of Goiás (UFG), Institute of Tropical Pathology and Public Health (IPTSP) - R. 235, s/n - Setor Leste Universitário - Goiânia/GO - CEP 74605-050, Brazil.
Vaccine ; 40(46): 6616-6624, 2022 Nov 02.
Article in English | MEDLINE | ID: covidwho-2106125
ABSTRACT

INTRODUCTION:

Brazil experienced moments of collapse in its health system throughout 2021, driven by the emergence of variants of concern (VOC) combined with an inefficient initial vaccination strategy against Covid-19.

OBJECTIVES:

To support decision-makers in formulating COVID-19 immunization policy in the context of limited vaccine availability and evolving variants over time, we evaluate optimal strategies for Covid-19 vaccination in Brazil in 2021, when vaccination was rolled out during Gamma variant predominance.

METHODS:

Using a discrete-time epidemic model we estimate Covid-19 deaths averted, considering the currently Covid-19 vaccine products and doses available in Brazil; vaccine coverage by target population; and vaccine effectiveness estimates. We evaluated a 5-month time horizon, from early August to the end of December 2021. Optimal vaccination strategies compared the outcomes in terms of averted deaths when varying dose intervals from 8 to 12 weeks, and choosing the minimum coverage levels per age group required prior to expanding vaccination to younger target populations. We also estimated dose availability required over time to allow the implementation of optimal strategies.

RESULTS:

To maximize the number of averted deaths, vaccine coverage of at least 80 % should be reached in older age groups before starting vaccination into subsequent younger age groups. When evaluating varying dose intervals for AZD1222, reducing the dose interval from 12 to 8 weeks for the primary schedule would result in fewer COVID-19 deaths, but this can only be implemented if accompanied by an increase in vaccine supply of at least 50 % over the coming six-months in Brazil.

CONCLUSION:

Covid-19 immunization strategies should be tailored to local vaccine product availability and supply over time, circulating variants of concern, and vaccine coverage in target population groups. Modelling can provide valuable and timely evidence to support the implementation of vaccination strategies considering the local context, yet following international and regional technical evidence-based guidance.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: Vaccines / COVID-19 Type of study: Experimental Studies / Observational study / Randomized controlled trials Topics: Vaccines / Variants Limits: Aged / Humans Country/Region as subject: South America / Brazil Language: English Journal: Vaccine Year: 2022 Document Type: Article

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Full text: Available Collection: International databases Database: MEDLINE Main subject: Vaccines / COVID-19 Type of study: Experimental Studies / Observational study / Randomized controlled trials Topics: Vaccines / Variants Limits: Aged / Humans Country/Region as subject: South America / Brazil Language: English Journal: Vaccine Year: 2022 Document Type: Article