Rivera-Perez, Daniela , Mendez, Constanza , Diethelm-Varela, Benjamin , Melo-Gonzalez, Felipe , Vazquez, Yaneisi , Meng, Xing , Xin, Qianqian , Fasce, Rodrigo A. , Fernandez, Jorge , Mora, Judith , Ramirez, Eugenio , Acevedo, Monica L. , Valiente-Echeverria, Fernando , Soto-Rifo, Ricardo , Grifoni, Alba , Weiskopf, Daniela , Sette, Alessandro , Astudillo, Patricio , Le Corre, Nicole , ABARCA LÓPEZ, CELIA, Perret, Cecilia , Gonzalez, Pablo A. , Soto, Jorge A. , Bueno, Susan M. , Kalergis, Alexis M. , PedCoronaVac03CL Study Grp
No
Front. Immunol.
Article
Científica
15/05/2024
001233705500001
Background: Vaccine effectiveness against SARS-CoV-2 infection has been somewhat limited due to the widespread dissemination of the Omicron variant, its subvariants, and the immune response dynamics of the naturally infected with the virus. Methods: Twelve subjects between 3-17 years old (yo), vaccinated with two doses of CoronaVac (R), were followed and diagnosed as breakthrough cases starting 14 days after receiving the second dose. Total IgGs against different SARS-CoV-2 proteins and the neutralizing capacity of these antibodies after infection were measured in plasma. The activation of CD4(+) and CD8(+) T cells was evaluated in peripheral blood mononuclear cells stimulated with peptides derived from the proteins from the wild-type (WT) virus and Omicron subvariants by flow cytometry, as well as different cytokines secretion by a Multiplex assay. Results: 2 to 8 weeks post-infection, compared to 4 weeks after 2(nd) dose of vaccine, there was a 146.5-fold increase in neutralizing antibody titers against Omicron and a 38.7-fold increase against WT SARS-CoV-2. Subjects showed an increase in total IgG levels against the S1, N, M, and NSP8 proteins of the WT virus. Activated CD4(+) T cells showed a significant increase in response to the BA.2 subvariant (p<0.001). Finally, the secretion of IL-2 and IFN-gamma cytokines showed a discreet decrease trend after infection in some subjects. Conclusion: SARS-CoV-2 infection in the pediatric population vaccinated with an inactivated SARS-CoV-2 vaccine produced an increase in neutralizing antibodies against Omicron and increased specific IgG antibodies for different SARS-CoV-2 proteins. CD4(+) T cell activation was also increased, suggesting a conserved cellular response against the Omicron subvariants, whereas Th1-type cytokine secretion tended to decrease.
inactivated SARS-CoV-2 vaccine; CoronaVac (R); pediatric; phase 3 clinical trial; omicron variant; breakthrough cases; SARS-CoV-2