key: cord-0289267-lw7sis3w authors: Ssuuna, C.; Galiwango, R. M.; Kankaka, E. N.; Kagaayi, J.; Ndyanabo, A.; Kigozi, G.; Nakigozi, G.; Lutalo, T.; Ssekubugu, R.; Wasswa, J. B.; Mayinja, A.; Nakibuuka, M. C.; Jamiru, S.; Oketch, J. B.; Muwanga, E.; Chang, L. W.; Grabowski, M. K.; Wawer, M.; Gray, R.; Anderson, M.; Stec, M.; Cloherty, G.; Laeyendecker, O.; Reynolds, S. J.; Quinn, T. C.; Serwadda, D. M. title: Severe Acute Respiratory Syndrome Coronavirus-2 seropositivity in South-central Uganda, during 2019 - 2021 date: 2021-09-16 journal: nan DOI: 10.1101/2021.09.13.21263414 sha: cc38a9ce7cab9e9711c03655000d93248868a01b doc_id: 289267 cord_uid: lw7sis3w Globally, key subpopulations have a high risk of contracting SARS-CoV-2. In Uganda, limited access to personal protective equipment amidst lack of clarity on the extent of the community disease burden may exacerbate this situation. We assessed SARS-CoV-2 antibody seroprevalence among high-risk sub-populations, including healthcare workers, persons within the general population previously reporting experiencing key COVID-19 like symptoms and archived plasma specimens collected prior to confirmation of COVID-19 in Uganda. We collected venous blood from HCWs at selected health facilities and from population-cohort participants who reported specific COVID-19 like symptoms in a prior phone-based survey conducted during the first national lockdown (May-August 2020). Pre-lockdown plasma collected from individuals considered high risk for SARS-CoV-2 infection was retrieved. Specimens were tested for antibodies to SARS-CoV-2 using the CoronaChekTM rapid COVID-19 IgM/IgG lateral flow test assay. IgM only positive samples were confirmed using a chemiluminescent microparticle immunoassay (ARCHITECT AdviseDx SARS-CoV-2 IgM) which targets the spike. SARS-CoV-2 exposure was defined as either confirmed IgM, both IgM and IgG or sole IgG positivity. The seroprevalence of antibodies to SARS-CoV-2 in HCWs was 21.1% [95%CI: 18.2-24.2]. Of the phone-based survey participants, 11.9% [95%CI: 8.0-16.8] had antibodies to SARS-CoV-2. Among 636 pre-lockdown plasma specimens, 1.7% [95%CI: 0.9-3.1] were reactive. Findings suggest a high seroprevalence of antibodies to SARS-CoV-2 among HCWs and substantial exposure in persons presenting with specific COVID-19 like symptoms in the general population of South-central Uganda. Based on current limitations in serological test confirmation, it remains unclear whether pre-lockdown seropositivity implies prior SARS-CoV-2 exposure in Uganda. It is over a year since SARS-CoV-2 emerged[1] as a global pandemic and as of the 2 nd of 54 August 2021, nearly two hundred million cases were reported globally with >4,000,000 55 fatalities [2] . Transmission occurs by respiratory droplets, aerosols, and via fomites and is higher 56 in confined or congested spaces [3] . SARS-CoV-2 infection can be asymptomatic [4] with estimates 57 ranging from 5% -80% while symptoms are largely nonspecific and include features of flu-like 58 illness [5] . Diagnosis of asymptomatic and mild cases may be missed due to prioritization of 59 screening/confirmatory tests for individuals with moderate to severe symptoms. However, 60 asymptomatic and pre-symptomatic persons can be highly contagious and contribute greatly to 61 epidemic spread [6, 7] . 62 As of the 3 rd of August 2021, more than 94,000 cases with 2,710 deaths were documented 63 in Uganda [2] . Community transmission is on the rise[8] despite earlier control measures that 64 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint The copyright holder for this this version posted September 16, 2021. ; https://doi.org/10.1101 https://doi.org/10. /2021 included a phased nationwide lockdown between March and August 2020 [9] . The SARS-CoV-2 65 diagnostic testing landscape in Uganda prioritizes testing for symptomatic persons. It is unknown 66 how many infected asymptomatic persons are missed due to this symptom-based testing approach 67 and what impact this has on community transmission. HCWs in particular are at a higher risk of contracting SARS-CoV-2[10, 11] and 69 inadvertently transmitting it to their patients, some of whom may be immunocompromised. According to the World Health Organization (WHO), they account for 10% of the global SARS- CoV-2 burden [12] . This risk may be higher in countries like Uganda, due to shortage of Personal 72 Protective Equipment (PPE) amidst unquantified community disease burden. Notably, several 73 HCWs in Uganda have been infected and a number have died [13] . Due to the limited testing capacity, there are likely to be many undetected community 75 infections fueling the epidemic. It is also unknown if SARS-CoV-2 importation or exposure in 76 Uganda might have occurred earlier than the first (official) case reported on the 21 st of March 77 2020. We aimed at determining the prevalence of antibodies to SARS-CoV-2 among selected high-78 risk sub-populations in South-central Uganda, including HCWs, persons who previously reported 79 specific COVID-19 like symptoms (fever, cough, loss of taste and smell) in the preceding 30 days, 80 between May and August 2020. Additionally, we aimed at exploring the possibility of prior SARS- CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint The copyright holder for this this version posted September 16, 2021. ; https://doi.org/10.1101 https://doi.org/10. /2021 National Council for Science and Technology (UNCST) (registration number HS878ES). Written 87 informed consent was obtained from participants before blood specimens and other data were 88 collected. Also, only archived pre-lockdown plasma specimens from Rakai Community Cohort 89 Study (RCCS) participants that had provided prior consent for use of their blood specimens in 90 future studies were retrieved to assess prior SARS-CoV-2 exposure in Uganda. Study design and setting: This study was cross-sectional and was conducted at the Rakai CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint Seropositivity was highest among nurses and lowest among medical officers ( Table 1) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this this version posted September 16, 2021. ; https://doi.org/10.1101 https://doi.org/10. /2021 CoronaChek TM , 16.3% of the participants (37/227) tested positive on IgM only, 2.2% (5/227) 151 tested positive on IgG only whereas 6.6% (15/227) were positive on both IgM and IgG. Following . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint The copyright holder for this this version posted September 16, 2021. ; https://doi.org/10.1101 https://doi.org/10. /2021 There are challenges interpreting SARS-CoV-2 rapid serology in regions with high malaria 171 endemicity as infection with Plasmodium species was shown to induce cross-reactive antibodies 172 to carbohydrate epitopes on the SARS-CoV-2 spike protein [17, 18] . It is thus unclear whether 173 seropositivity in pre-lockdown plasma specimens implies prior SARS-CoV-2 or other related 174 coronavirus exposure or malaria in Uganda. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint Other staff 75 (47.2) 1.0 (0.7-1.5) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint The copyright holder for this this version posted September 16, 2021. ; https://doi.org/10.1101 https://doi.org/10. /2021 Protocol development: Ronald M. Galiwango Clinical and virological data of the first cases of COVID-19 in Europe: a case 203 series. The Lancet Infectious Diseases United 205 States Transmission of SARS-CoV-2: a review of viral, host, and environmental 207 factors. 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