foto Dr. Carlos SariolCarlos A. Sariol, MD, MSc

“Immunological Characterization of the Immune Response to COVID-19 in Puerto Rico”

Dr. Sariol completed his MD in the University of Medical Sciences, Havana, Cuba, and a Fellowship in Clinical microbiology and a master’s in sciences in Molecular Virology from the Institute of Tropical Medicine “Pedro Kouri”, Havana, Cuba. After that, he completed a Post Doc in Tubingen, Germany. Since 2002 he has been Director of the Virology Laboratory, Caribbean Primate Research Center, Puerto Rico and since 2012 he also heads the Unit of Comparative Medicine at the Medical Sciences Campus, University of Puerto Rico. Flaviviruses, including dengue and Zika are the main focus of his research career. His work has been published in high profile Journals like Nature Communications, PNAS, PLOS Neglected Tropical Diseases and others. During the COVID-19 pandemic he applied his expertise and knowledge as Virologist to implement de diagnostic of and to characterize the immune response to SARS-CoV-2 virus. His research work is currently funded by P40, R01 and U01 mechanisms from the National Institutes of Health.


Project Summary

On this work, we report that despite a decline in the IgG titers and isotypes levels the neutralizing antibodies remain at a similar level for an average of 98 days in a longitudinal cohort of 59 Hispanic/Latino population exposed to SARS-CoV-2. We are also reporting that these neutralizing titers correlate with the total IgG titers being IgG1(62.71%) the predominant subclass in the first post-infection sample, followed by IgG4 (15.25%), IgG3 (13.56%), and IgG2 (8.47%) during the tested period. The IgA was detectable in 28.81% of subjects in the first sample. Only 62.71% of all subjects have detectable IgM in the first sample despite of confirmed infection by a molecular method. While our work included only one subject who required hospitalization, we were able to determine that the dynamics of neutralizing antibodies over time was not associated to a symptomatic clinical presentation regardless the age or sex.  Our data suggest that in 100% of seroconverted subjects there are detectable neutralizing antibody responses which were measured by a surrogate viral neutralization test (sVNT). Interestingly, 6 have neutralizing activity without detectable IgG titers. We also found that the IgG titers and neutralizing levels, in 7 out from 59 plus other 3 vaccinated subjects with prior infection, were similar or higher after the first dose compared to the levels reached after the second dose in a subgroup of 21 subjects naïve to SARS-CoV-2. Also, we are showing that the vaccine induces a faster expansion of the IgA in pre-exposed individuals compared to the virus-naïve population. This work is an essential contribution to understand the natural immune response to the novel coronavirus in a population severely hit by the virus. Also provides invaluable data to be compared with the dynamic of the immune response induced by the vaccines in pre-exposed versus naïve individuals.