ANATIONAL SEROPREVALENCE SURVEY of SARS-CoV-2 ANTIBODIES in SOUTH AFRICA: 2020-2021

Background: South Africa is one of the African countries most affected by the COVID-19 pandemic. SARS-CoV-2 seroprevalence surveys provide valuable epidemiological information given the existence of asymptomatic cases. We report the findings of the first nationwide household-based population estimates of SARS-CoV-2 seroprevalence among people aged 12 years and older in South Africa. Methods: The survey used a cross-sectional multi-stage stratified cluster design undertaken over two separate time periods (November 2020-February 2021 and April-June 2021) which coincided with the second and third waves of the pandemic in South Africa. The Abbott® and Euroimmun® ani-SARS CoV-2 antibody assays were used to test for SARS-CoV-2 antibodies, the latter being the final result. The survey data was weighted with final individual weights benchmarked against 2020 mid-year population estimates by age, race, sex, and province. Frequencies were used to describe characteristics of the study population and SARS-CoV-2 seroprevalence. Bivariate and multivariate logistics regression analysis were used to identify factors associated with SARS-CoV-2 seropositivity. Results: 13640 participants gave a blood sample. The SARS-CoV-2 seroprevalence using the Euroimmun assay was 19.6% (95% CI 17.9-21.3) over the study period, translating to an estimated 8 675 265 (95% CI 7 508 393-9 842 137) estimated infections among people aged 12 years and older across South Africa by June 2021. Seroprevalence was higher in the Free State (26.8%), and Eastern Cape (26.0%) provinces (Figure). Increased odds of seropositivity were associated with prior PCR testing [aOR=1.29 (95% CI: 0.99-1.66)], being female [aOR=1.28 (95% CI 1.00-1.64), p=0.048] and hypertension, [aOR=1.28 (95% CI 1.00-1.640, p=0.048]. Conclusion: These findings highlight the burden of infection in South Africa by June 2021, and support testing strategies that focus on individuals with known exposure or symptoms since universal testing is not feasible. Females and younger people were more likely to be infected suggesting need for additional strategies targeting these populations. The estimated number of infections was 6.5 times higher than the number of SARS-CoV-2 cases reported nationally, suggesting that the country's testing strategy and capacity partly explain the dynamics of the pandemic. It is therefore essential to bolster testing capacity and to rapidly scale up vaccinations in order to contain the spread of the virus in the country.

PERFORMANCE of SARS-CoV-2 ANTIBODY ASSAYS in A NATIONAL SEROSURVEY in SOUTH AFRICA

Background: Accurate and reliable serological assays are essential for epidemiological surveillance of SARS-CoV-2. Several commercial anti-SARS assays are available and use cases for serological testing includes surveillance. However, there is growing evidence of varying performance of SARS-CoV-2 assays dependent of their format. We compare the performance of 3 different assays used in a national serosurvey undertaken between April and June 2021, in South Africa before widescale vaccination roll out. Methods: Venous blood samples from participants ≥12 years were transported under cold chain to a central testing laboratory within 24 hours of collection. Samples were tested for SARS CoV-2 antibodies with the Abbott nucleocapsid (NC)-based Architect anti-SARS CoV-2 chemiluminescent microparticle immunoassay (CMIA), the EuroImmun Spike (S)-based assay and the Roche total IgG NC-based Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay (ECLIA) on the Cobas e411 platform. We compared antibody detection proportions. Results: 8146 participants (median age 40 years, IQR 26-55) 5.6% of whom reported ≥1 SARS-CoV-2 symptom in the preceding 3 months gave a blood sample. Samples were tested on the Abbott assay with different cut-offs:-15.5% tested positive at the 1.40 cut-off and 26.8% at the 0.49 lower cut-off. 21.6% of the samples tested positive on the Euroimmun and 39.0% tested positive on the Roche assay (Table). 286 samples were from respondents self-reporting a prior positive PCR test, and among them 149(52.1%), 156(54.6%), and 206(72.3%) were positive on the Abbott (1.40 cut-off), Euroimmun and Roche assays respectively. 116/286(40.6%) of these were positive on all three assays and with 21(7.3%) positive on Roche only. 224/286(78.3%) of those reporting prior PCR test positivity were positive at the lower Abbott cut-off, with 47(16.4%) positive on Abbott only. Conclusion: These samples collected before wide scale vaccination roll out in South Africa show variable performance of these assays with the Roche NC assay detecting more infections that both the Abbott NC assay(0.40 cut-off) and the Euroimmun S assay.This could be reflective of seroreversion previously reported with Abbott and Euroimmun, and the greater sensitivity of Roche assay targeting the more abundant NC as an epitope. Use of direct, double Antigen-sandwich-based assays that are stable and have increased sensitivity over time may be optimal to detect both natural and vaccine-induced immunity in serosurveys.

Spatial analysis of perceived health system capability and actual health system capacity for covid-19 in south africa

Introduction: People’s confidence in the health system's capability in managing the COVID-19 pandemic can determine public support, risk perceptions, and compliance to the required behaviors during the pandemic. Therefore, this paper investigated people’s perception of health system capability to manage the COVID-19 pandemic in different spatial areas across the country using data from an online survey. Methods: Multivariate logistic regression models were used to examine factors associated with people’s perception of the health system capability to manage the COVID-19 pandemic at the national and provincial levels. Spatial comparative analysis was conducted to contrast spatial density indicators of the number of hospitals, hospital beds, and ICU beds per given population across various provinces. Results: Findings showed that South Africans had low confidence in the health system capability, with only two in five (40.7%) reporting that they thought that the country’s health system was able to manage the COVID-19 pandemic. Sex and knowledge on COVID-19 were significantly associated with the people’s perception of the health system capability to manage the pandemic at the national level and in four of the nine provinces. Conclusion: Overall, the findings of this study clearly highlight challenges facing the country’s health system, both perceived or real, that needed to be addressed as part of the preparation for the COVID-19 pandemic. Timeous implementation of a countrywide National Health Insurance (NHI) system is now more critical than ever in improving healthcare outcomes of the South African population beyond the existence of the COVID-19 epidemic.

Compliance with lockdown regulations during the covid-19 pandemic in south africa: Findings from an online survey

Background: Background: SARS-CoV-2 has resulted in the COVID-19 pandemic. Based on a nationally representative online survey conducted several weeks on the pandemic, this paper explores how South Africans responded to the compliance regulations laid down by the national government and factors associated with individuals’ confidence in their community adhering to lockdown regulations. Methods: The study was conducted using a closed-ended questionnaire on a data-free online platform. Additionally, a telephonic survey was included to accommodate individuals who do not have access to smart-phones. The study population consisted of respondents who were 18 years and older and living in South Africa (n=19 933). Data were benchmarked to the 2019 midyear population estimates. Descriptive statistics and bivariate logistic regression are presented. Results: Over a quarter (26.1%) of respondents reported that they had not left home, indicating compliance with the COVID-19 control regulations, and 55.3% who did leave their homes did so to purchase essential items. A small proportion (1.2%) reported that they had visited friends. People, classified as coloured, those who were more literate (those with secondary, matric and tertiary education status), those residing in disadvantaged areas (informal settlements, townships, rural areas and farms), and those who perceived their risk of contracting COVID-19 as moderate and high, reported not being confident of their community adhering to lockdown. Conclusion: Communication strategies must be employed to ensure that important information regarding the pandemic be conveyed in the most important languages and be dispatched via various communication channels to reach as many people as possible.

South Africans' understanding of and response to the COVID-19 outbreak: An online survey.

BACKGROUND: The COVID-19 outbreak is in an accelerating phase, and South Africa (SA) has had the highest number of documented cases during the early phase of the pandemic in sub-Saharan Africa. OBJECTIVES: To assess South Africans' understanding of and response to COVID-19 during the first week of the country's lockdown period. METHODS: An online survey was conducted in SA from 27 March to 2 April 2020. The survey was distributed widely among several websites and social media networks, including on a data-free platform. Descriptive statistics of knowledge, risk perception, access to and trust in information sources, and public and media opinions were calculated. Estimates were benchmarked to the 2019 national adult population estimates. RESULTS: Of the 55 823 participants, the majority (83.4%) correctly identified the main symptoms of COVID-19. Over 90% had correct knowledge of the incubation period, with lower rates for 18 - 29-year-olds. Knowledge of symptoms and the incubation period varied significantly by population group (p<0.001), dwelling type (p<0.001) and sex (p<0.001). A quarter (24.9%) perceived themselves as at high risk of contracting COVID-19. Risk perception varied by age, population group, employment status and dwelling type (p<0.001). The most prevalent COVID-19 information sources were government sources (72.9%), news websites/apps (56.3%), satellite television (51.6%) and local television (51.4%). CONCLUSIONS: Understanding knowledge, attitudes and behaviours of people facing the COVID-19 pandemic is crucial for guiding strategic policy. These findings provide public understanding of COVID-19 as the phases of the country-level epidemic progress, and also directly inform communication needs and gaps.