Generation of neutralizing antibodies against Omicron, Gamma and Delta SARS-CoV-2 variants following CoronaVac vaccination

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 1:40, 1:20 and 1:20 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.

COVID‐19 pandemic in Southern Brazil: Hospitalizations, intensive care unit admissions, lethality rates, and length of stay between March 2020 and April 2022

“…More recently, the spread of the omicron variant has returned the alert for the progression and evolution of the pandemic, even though mass vaccination and herd immunity were already established, the number of cases and occupations in the intensive care unit (ICU) were worrying between January and March 2022. 10 , 11 , 12 In this sense, it is essential to study the outcomes of hospitalizations, ICU admission, use of mechanical ventilation, readmissions, and lethality to qualify and quantify the impact of COVID‐19 on the hospital system. 5 , 6 , 7 , 8 , 9 , 13 , 14 , 15 …”

“…[5][6][7][8][9] More recently, the spread of the omicron variant has returned the alert for the progression and evolution of the pandemic, even though mass vaccination and herd immunity were already established, the number of cases and occupations in the intensive care unit (ICU) were worrying between January and March 2022. [10][11][12] In this sense, it is essential to study the outcomes of hospitalizations, ICU admission, use of mechanical ventilation, readmissions, and lethality to qualify and quantify the impact of COVID-19 on the hospital system. [5][6][7][8][9][13][14][15] Therefore, the present study aims to evaluate the number of hospitalizations, ICU admissions, mortality rates, use of mechanical ventilation, and length of stay (LOS) in COVID-19 admission between March 2020 and April 2022 in southern Brazil.…”

Third dose of anti-SARS-CoV-2 inactivated vaccine for patients with RA: Focusing on immunogenicity and effects of RA drugs

“…NAb titer levels are positively correlated with vaccine protection, and ongoing disease surveillance studies can be conducted to assess vaccine protection's durability better. Studies have found that three doses of mRNA vaccine increased serum antibody responses to multiple SARS-CoV-2 variants ( 17 , 18 ). A booster with SARS-CoV-2 vaccines can increase NAb levels and prevent the infection of omicron or future variants ( 19 ).…”

“…Studies have found that three doses of mRNA vaccine increased serum antibody responses to multiple SARS-CoV-2 variants (17,18). A booster with SARS-CoV-2 vaccines can increase NAb levels and prevent the infection of omicron or future variants (19).…”

Two years of COVID-19 pandemic: Framework of health interventions in a Brazilian city

“…Throughout this second wave a decrease in mobility was observed in four categories: retail and recreation, grocery and pharmacy, transit stations and workplaces. However, the increase in mobility in the grocery and pharmacy category associated with Christmas (week 39) could have contributed to an enlarged wave as well as its highest peaks during this second wave (weeks [41][42][43].…”