Antibody response to SARS-CoV-2 infection over six months among Nicaraguan outpatients

Abstract

New information is emerging about SARS-CoV-2 epidemiology and immunity, but little of this information comes from low- and middle-income countries or from patients receiving care in the outpatient setting. The current study investigated the SARS-CoV-2 infection status and antibody responses in 157 patients seeking care for a respiratory disease suggestive of COVID-19 in private healthcare clinics during the first wave (June-October 2020) of infections in Nicaragua. We examined nasal swabs for the presence of viral RNA via RT-PCR and longitudinally collected sera for the changes in SARS-CoV-2 Spike antibody levels over six months. Among patients with confirmed SARS-CoV-2 infections, we evaluated if clinical symptoms were associated with age, hematological parameters and co-morbidities. The combination of PCR and paired serology identified 60 (38%) of the 157 outpatients as acute COVID-19. While both PCR and serology identified the majority (n = 38, 64%) of the acute infections, a notable number of outpatients were identified by RT-qPCR (n = 13, 22%) or by serology (n = 9, 14%) only. During the longitudinal study, we identified 6 new infections by serology among the 97 non-COVID-19 subjects. In conclusion, this study report that more than one third of the outpatients seeking care for acute respiratory disease during the first epidemic wave of SARS-CoV-2 in Nicaragua had an acute mild COVID-19 infection that correlate with prolonged humoral response. This immune response to the RBD antigen, more likely IgG dependent, significantly increased between the acute to convalescent and decay in the late convalescent but still remained seropositive.

Seroepidemiology of SARS-CoV-2 infections in an urban population-based cohort in León, Nicaragua

“…A study of outpatients seeking care for acute respiratory disease during the first epidemic wave of SARS-CoV-2 in León showed that 38% had an acute mild COVID-19 infection. 19 A recent cross-sectional study of Nicaraguan health care workers (HCWs) conducted over one month found that 30% of participants had active SARS-CoV-2 infection based on amplification of the SARS-CoV-2 RNA in saliva samples. When accounting for resolved infections in which virus would not be detected, it is likely that SARS-CoV-2 seroprevalence among HCWs is even higher than the infection prevalence, suggesting that seroprevalence among Nicaraguan health care workers is likely higher than in the general population.…”