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Generation of neutralizing antibodies against Omicron, Gamma and Delta SARS-CoV-2 variants following CoronaVac vaccination.
Silva, Almir Ribeiro da; Villas-Boas, Lucy Santos; Tozetto-Mendoza, Tania Regina; Honorato, Layla; Paula, Anderson de; Witkin, Steven S; Mendes-Correa, Maria Cassia.
  • Silva ARD; Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, São Paulo, Brazil.
  • Villas-Boas LS; Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
  • Tozetto-Mendoza TR; Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
  • Honorato L; Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
  • Paula A; Universidade de São Paulo, Faculdade de Medicina, Instituto de Medicina Tropical de São Paulo, São Paulo, São Paulo, Brazil.
  • Witkin SS; Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
  • Mendes-Correa MC; Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
Rev Inst Med Trop Sao Paulo ; 64: e19, 2022.
Article in English | MEDLINE | ID: covidwho-1725113
ABSTRACT
Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 140, 120 and 120 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: SARS-CoV-2 / COVID-19 Type of study: Experimental Studies Topics: Vaccines / Variants Limits: Humans Country/Region as subject: South America / Brazil Language: English Journal: Rev Inst Med Trop Sao Paulo Year: 2022 Document Type: Article Affiliation country: S1678-9946202264019

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Full text: Available Collection: International databases Database: MEDLINE Main subject: SARS-CoV-2 / COVID-19 Type of study: Experimental Studies Topics: Vaccines / Variants Limits: Humans Country/Region as subject: South America / Brazil Language: English Journal: Rev Inst Med Trop Sao Paulo Year: 2022 Document Type: Article Affiliation country: S1678-9946202264019