Robust specific RBD responses and neutralizing antibodies after ChAdOx1 nCoV-19 and CoronaVac vaccination in SARS-CoV-2- seropositive individuals

Edgar Ruz Fernandes; Monica Taminato; Juliana de Souza Apostolico; Maria Cristina Gabrielonni; Victoria Alves Santos Lunardelli; Juliana Terzi Maricato; Monica Levy Andersen; Sergio Tufik; Daniela Santoro Rosa

doi:10.1016/j.jacig.2023.100083

Robust specific RBD responses and neutralizing antibodies after ChAdOx1 nCoV-19 and CoronaVac vaccination in SARS-CoV-2- seropositive individuals

J Allergy Clin Immunol Glob. 2023 May;2(2):100083. doi: 10.1016/j.jacig.2023.100083. Epub 2023 Feb 21.

Affiliations

¹ Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo (UNIFESP), São Paulo.
² Escola Paulista de Enfermagem, Universidade Federal de São Paulo (UNIFESP), São Paulo.
³ Departamento de Psicobiologia, Universidade Federal de São Paulo (UNIFESP), São Paulo.
⁴ Instituto do Sono, São Paulo.

Abstract

Background: The pandemic unleashed by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 500 million people worldwide and caused more than 6 million deaths. Cellular and humoral immunity induced by infection or immunization are key factors in controlling the viral burden and avoiding the recurrence of coronavirus disease. The duration and effectiveness of immunity after infection is relevant to pandemic policy interventions, including the timing of vaccine boosters.

Objectives: We sought to evaluate longitudinal binding and functional antibodies against SARS-CoV-2 receptor-binding domain in police officers and health care workers with a history of coronavirus disease 2019 and compare with SARS-CoV-2-naive individuals after vaccination with adenovirus-based ChAdOx1 nCoV-19 (AstraZeneca-Fiocruz) or the inactivated CoronaVac vaccine (Sinovac-Butantan Institute).

Methods: A total of 208 participants were vaccinated. Of these, 126 (60.57%) received the ChAdOx1 nCoV-19 vaccine and 82 (39.42%) received the CoronaVac vaccine. Prevaccination and postvaccination blood was collected, and the amount of anti-SARS-CoV-2 IgG and the neutralizing ability of the antibodies to block the interaction between angiotensin-converting enzyme 2 and receptor-binding domain were determined.

Results: Subjects with preexisting SARS-CoV-2 immunity and who received a single dose of ChAdOx1 nCoV-19 or CoronaVac have similar or superior antibody levels when compared with levels in seronegative individuals even after 2 doses of the vaccine. Neutralizing antibody titers of seropositive individuals were higher with a single dose of either ChAdOx1 nCoV-19 or CoronaVac compared with those of seronegative individuals. After 2 doses, both groups reached a plateau response.

Conclusions: Our data reinforce the importance of vaccine boosters to increase specific binding and neutralizing SARS-CoV-2 antibodies.

Keywords: AU, Arbitrary units; COVID-19; COVID-19, Coronavirus disease 2019; ChAdOx1 nCoV-19; CoronaVac; RBD, Receptor-binding domain; SARS-CoV-2; SARS-CoV-2, Severe acute respiratory syndrome coronavirus 2; antibodies; sVNT, Surrogate Virus Neutralization Test.