Early Evidence of Circulating SARS-CoV-2 in Unvaccinated and Vaccinated Measles Patients, September 2019–February 2020

Abstract

Background The global emergence of coronavirus disease 2019 (COVID-19) has challenged healthcare and rapidly spread over the globe. Early detection of new infections is crucial in the control of emerging diseases. Evidence of early recorded COVID-19 cases outside China has been documented in various countries. In this study, we aimed to identify the time of SARS-CoV-2 infection circulation by retrospectively analyzing sera of measles patients, weeks before the reported first COVID-19 cases in Angola. Materials and Methods We examined the humoral response against SARS-CoV-2 by using an enzyme-linked immunosorbent assay (ELISA)-based assay on a combined two-step sandwich enzyme immunoassay method. In total, we received 568 study patients with blood specimens collected from 23 September 2019 to 28 February 2020, 442 sera samples that met the criteria of the study were withdrawn and selected from the overall 568 received samples. In this study, we considered seropositives, patients who tested positive for SARS-CoV-2 immunoglobulin G (IgG) and M (IgM) antibodies with the index value >1. Results Of the 442 sera samples that met the criteria of the study, 204 were measles seropositive. Forty out of 204 were confirmed reactive to SARS-CoV-2 viral proteins using IgG and IgM more than 2 weeks before the first reported case in Angola. The humoral response analysis showed significant differences ( p = 0.01) between the IgG and IgM indexes in the unvaccinated measles patients. Similarly, a significant difference ( p = 0.001) was seen between the IgG and IgM indexes in the vaccinated measles patients. Conclusion Here, using the humoral response analysis, we report the identification of early circulation SARS-CoV-2 infection weeks before the first recognized cases in the Republic of Angola.

Insights into SARS‐CoV‐2 in Angola during the COVID‐19 peak: Molecular epidemiology and genome surveillance

“…Our analyses indicated that the first introduction event was inferred during the first months of 2020, and most likely originated from Southern African countries, despite the first reported case being linked to Portugal (Figure 1A). In agreement with previous findings, 29 our analyses indicated that cases may have occurred undetected before the first case was reported. Similar to Brazil and Portugal, the high level of virus introduction and exportation events noted between Angola, Namibia, and South Africa were most likely due to their strong economic ties, particularly in the mining and construction sectors, and many Angolans travel to South Africa and Namibia for business, education, and tourism purposes 25 .…”

Molecular evidence for SARS-CoV-2 in samples collected from patients with morbilliform eruptions since late 2019 in Lombardy, northern Italy

“…Several lines of evidence suggest that SARS-CoV-2 had already been spreading unnoticed for some time prior to being recognized. In fact, SARS-CoV-2 RNA was detected in wastewaters in Northern Italy in late December 2019 ( La Rosa et al, 2021 ) and in Brazil in November 2019 25 , and there is some indirect evidence of 2019 infections through antibody detection in France ( Carrat et al, 2021 ), Italy ( Apolone et al, 2020 ; Montomoli and E, 1401 ), UK ( Ng et al, 2020 ), the USA ( Basavaraju et al, 2021 ), and Angola ( Paixao et al, 2022 ). In addition, SARS-CoV-2 RNA was detected as early as December 2019 in a respiratory sample from a French patient hospitalized for haemoptysis ( Deslandes et al, 2020 ), in the oropharyngeal swab from a child from Milan (Lombardy) with suspected measles ( Amendola et al, 2021 ), and in the blood and lungs of a patients that died in Milan because of acute circulatory insufficiency ( Lai et al, 2022 ).…”

Assessment of the yellow fever outbreak in Angola from December 2015 through December 2016: A retrospective study

“…To stop the reaction, 100 mL of 1% SDS (sodium dodecyl sulfate) was added. When a cross‐reactive sample showed at least a twofold rise in titer, it was deemed positive; otherwise, the result suggested a potential cross‐reaction between flaviviruses 17,18 …”