AUTHOR=Medeiros Giuliana X. , Sasahara Greyce Luri , Magawa Jhosiene Y. , Nunes João Paulo S. , Bruno Fernanda R. , Kuramoto Andreia C. , Almeida Rafael R. , Ferreira Marcelo A. , Scagion Guilherme P. , Candido Érika D. , Leal Fabyano B. , Oliveira Danielle B. L. , Durigon Edison L. , Silva Roberto Carlos V. , Rosa Daniela S. , Boscardin Silvia B. , Coelho Verônica , Kalil Jorge , Santos Keity S. , Cunha-Neto Edecio 

TITLE=Reduced T Cell and Antibody Responses to Inactivated Coronavirus Vaccine Among Individuals Above 55 Years Old

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.812126

DOI=10.3389/fimmu.2022.812126

ISSN=1664-3224

ABSTRACT=CoronaVac is an inactivated SARS-CoV-2 vaccine that has been rolled out in several low and middle income countries including Brazil, where it was the mainstay of the first wave of immunization of 
healthcare workers and the elderly population. We aimed to assess the T cell and antibody responses 
of vaccinated individuals as compared to convalescent patients. We detected IgG against SARS-CoV-2 antigens, neutralizing antibodies against the original SARS-CoV-2 strain and used SARS-CoV-2 
peptides to detect IFN-g and IL-2 specific T cell responses in a cohort of CoronaVac vaccinated 
individuals (N=101) and convalescent (N=72) individuals. Among vaccinated individuals, 95% 
displayed T cell or antibody responses to SARS-CoV-2 as compared to 99% convalescent individuals. 
However, we observed that among vaccinated individuals, males and individuals 55 years or older 
developed significantly lower anti-RBD, anti-NP and neutralization titers against the Wuhan strain as 
well as antigen-induced IL-2 production by T cells. Neutralizing antibody responses for variants 
Gamma and Zeta were even lower than for the Wuhan strain. Even though some studies indicated 
CoronaVac helped reduce mortality among elderly people, considering the current dominance of the 
gamma variant of concern (VOC) and potential increase of the delta VOC, in Brazil, our data support 
that CoronaVac vaccinated individuals above 55 years old are likely to benefit from a heterologous 
third dose/booster vaccine to increase immune response and likely protection.