Caracterização das respostas humorais em infecções por Flavivirus e por SARS-COV-2

Abstract

Infectious diseases are capable of affecting human health with their potential to generate large pandemics and local epidemics. Amazon Region is endemic for emerging flaviviruses of public health relevance and is now facing a health pandemic caused by coronaviruses that cause severe acute respiratory syndrome. Hence, our aim was evaluating antibody responses in flavivirus and SARS-CoV-2 infections in Manaus city residents. The samples were submitted to serological analysis by hemagglutination inhibition assay (HIA), enzyme-linked immunosorbent assay (ELISA) using recombinant antigens and neutralization tests, investigating correlating risk factors. Flavivirus: for healthy military personnel, HIA-seropositivity rates were 60.4%, 30.9%, 46.6%, 54.7%, 51.3% and 48.7% for the dengue virus (DENV), Zika virus (ZIKV), West Nile virus (WNV), Saint Louis encephalitis virus, Ilhéus virus and Rocio virus, respectively. Regarding individuals from Manaus urban area, we observed a high DENV seropositivity (93.7%) and also yellow fever vaccine strain (92.8%) by HIA, showing greater prevalence in males and elevated reactivity since age twenty years. Anti-ZIKV antibodies were the least prevalent (52.6%). We demonstrate the same scenario of increased DENV reactivity and lower for ZIKV by ELISA against the envelope protein. Additionally, high DENV serum titers neutralized ZIKV more efficiently. We observed decreased reactivity for DENV-3 and DENV-4 compared to DENV-2 and DENV-1 by IH; and great DENV titers reacted more frequently with ZIKV or WNV in both populations. SARS-CoV-2: a multidimensional analysis revealed a temporal pattern of progressive increase of antibody response toward different immunogenic regions. The robust response was directly proportional to the disease severity; however, the robust antibody response was not sufficient to protect individuals with severe infection and control of inflammation. In summary, military personnel serving in Amazon could serve as sentinels to strengthen global infectious disease surveillance, particularly in remote areas. COVID-19 pandemic has negatively affected mosquito control measures. Presently, Brazil and Amazon region faces a complex epidemiological scenario characterized by simultaneous circulation of several arboviruses, hence a functional vector control program and febrile-syndrome surveillance is essential to identify unforeseen epidemiological threats. Furthermore, additional cohort studies assessing post-infection or vaccination persistent antibodies against SARS-CoV-2 in protective immune response may be needed.