First outbreak of COVID-19 in Cuba. Risk factors for morbidity and mortality and specific antibody response in convalescents
Keywords:
COVID-19, Cuba, epidemiological studies, polymorphisms, neutralizing antibodies, immune responseAbstract
Introduction: The variability in clinical severity among patients with COVID-19 and the development of severe symptoms, as well as the evolution of convalescents, may be due to possible models that combine genetic and non-genetic risk factors.
Objective: To characterize the risk factors for morbidity and mortality and the specific response of anti-SARS-CoV-2 antibodies during convalescence, in relation to severity, in patients recovered from the first COVID-19 outbreak in Cuba.
Methods: It was carried out a cross-sectional study of 1182 cases confirmed between March 11th and June 11th of 2020. They were divided into three groups: asymptomatic, those with mild or moderate symptoms and severely ill patients. They were determined the ABO blood group, the study of gene polymorphisms related to the immune response, lymphocyte subpopulations, and the anti-SARS-CoV-2 antibody response in convalescence. They were also analyzed data of 84 deaths by COVID-19.
Results: The risk of death after contracting the disease was 12.6 times higher in persons over 60 years of age (95%CI 6.3;25.2), and 2.4 times higher in men than in women (95% CI 1.4;4.2). Persons with chronic kidney disease, diabetes mellitus or cancer, had a higher risk of dying. They were identified the -308A>G polymorphisms of the TNF alpha gene, A16974C of the IL-12 p40 gene, and TaqI of the VDR gene as possible predisposing factors for the development of symptomatic forms. It was found in convalescent patients with severe forms an increase in CD3 + CD8 + and NK cells. It was found total anti-SARS-CoV-2 antibodies in the serum in 62.2% of the convalescents (95% CI 59.1;65.4). Seropositivity to total anti-SARS-CoV-2 antibodies, specific IgG antibody titers against the receptor-binding domain (RBD), its ability to inhibit the RBD-angiotensin-converting enzyme 2 (ACE2) receptor bond and its avidity, were higher in cases with severe forms of COVID-19.
Conclusions: The vulnerabilities identified in population groups, as well as the characteristics of the humoral anti-SARS-CoV-2 response during convalescence, provided useful evidence for the dynamic updating of the action protocols in the country, including the immunization strategies. This study allowed us to have our own references to evaluate the immunogenicity of Cuban vaccine candidates.
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