TRENDS IN CASES, HOSPITALISATION AND MORTALITY RELATED TO THE OMICRON BA.4/BA.5 SUB-VARIANTS IN SOUTH AFRICA (preprint)

Introduction: The Omicron BA.1/BA.2 wave in South Africa had lower hospitalisation and mortality than previous SARS-CoV-2 variants and was followed by an Omicron BA.4/BA.5 wave. This study compared admission incidence risk across waves, and the risk of mortality in the Omicron BA.4/BA.5 wave, to the Omicron BA.1/BA.2 and Delta waves. Methods: Data from South Africa's national hospital surveillance system, SARS-CoV-2 case linelist and Electronic Vaccine Data System were linked and analysed. Wave periods were defined when the country passed a weekly incidence of 30 cases/100,000 people. Mortality rates in the Delta, Omicron BA.1/BA.2 and Omicron BA.4/BA.5 wave periods were compared by post-imputation random effect multivariable logistic regression models. Results: In-hospital deaths declined 6-fold from 37,537 in the Delta wave to 6,074 in the Omicron BA.1/BA.2 wave and a further 7-fold to 837 in the Omicron BA.4/BA.5 wave. The case fatality ratio (CFR) was 25.9% (N=144,798), 10.9% (N=55,966) and 7.1% (N=11,860) in the Delta, Omicron BA.1/BA.2, and Omicron BA.4/BA.5 waves respectively. After adjusting for age, sex, race, comorbidities, health sector and province, compared to the Omicron BA.4/BA.5 wave, patients had higher risk of mortality in the Omicron BA.1/BA.2 wave (adjusted odds ratio [aOR] 1.43; 95% confidence interval [CI] 1.32-1.56) and Delta (aOR 3.22; 95% CI 2.98-3.49) wave. Being partially vaccinated (aOR 0.89, CI 0.86-0.93), fully vaccinated (aOR 0.63, CI 0.60-0.66) and boosted (aOR 0.31, CI 0.24-0.41); and prior laboratory-confirmed infection (aOR 0.38, CI 0.35-0.42) were associated with reduced risks of mortality. Conclusion: Overall, admission incidence risk and in-hospital mortality, which had increased progressively in South Africa's first three waves, decreased in the fourth Omicron BA.1/BA.2 wave and declined even further in the fifth Omicron BA.4/BA.5 wave. Mortality risk was lower in those with natural infection and vaccination, declining further as the number of vaccine doses increased.

Rapid rise in paediatric COVID-19 hospitalisations during the early stages of the Omicron wave, Tshwane District, South Africa (preprint)

Background South Africa reported a notable increase in COVID-19 cases from mid-November 2021 onwards, starting in Tshwane District, linked to rapid community spread of the Omicron variant. This coincided with a rapid rise in paediatric COVID-19-associated hospitalisations. Methods We synthesized data from five sources to describe the impact of Omicron on clinical manifestations and outcomes of hospitalized children ([≤]19 years) with positive SARS-CoV-2 tests in Tshwane District from 31 October to 11 December 2021, including: 1) COVID-19 line lists; 2) collated SARS-CoV-2 testing data; 3) SARS-CoV-2 genomic sequencing data; 4) COVID-19 hospitalisation surveillance; and 5) clinical data of public sector paediatric ([≤]13 years) COVID-19 hospitalisations. Findings During the six-week period 6,287 paediatric ([≤]19 years) COVID-19 cases were recorded in Tshwane District, of these 462 (7.2%) were hospitalized in 42 hospitals (18% of overall admissions). The number of paediatric cases was higher than in the prior 3 waves, uncharacteristically preceding adult hospitalisations. Of the 75 viral specimens sequenced from the district, 99% were Omicron. Detailed clinical information obtained from 139 of 183 (76%) admitted children ([≤]13 years; including all public sector hospitalisations) indicated that young children (0-4 years) were most affected (62%). Symptoms included fever (47%), cough (40%), vomiting (24%), difficulty breathing (23%), diarrhoea (20%) and convulsions (20%). Length of hospital stay was short (mean 3.2 days), and in 44% COVID-19 was the primary diagnosis. Most children received standard ward care (92%), with 31 (25%) receiving oxygen therapy. Seven children (6%) were ventilated; four children died, all related to complex underlying co-pathologies. All children and majority of parents for whom data were available were unvaccinated. Interpretation Rapid increases in paediatric COVID-19 cases and hospitalisations mirror high community transmission of SARS-CoV-2 (Omicron variant) in Tshwane District, South Africa. Continued monitoring is needed to understand the long-term impact of the Omicron variant on children.

SARS-CoV-2 Cases Reported From Long-Term Residential Facilities (Care Homes) in South Africa: A Retrospective Cohort Study (preprint)

Background: Globally, long-term care facilities (LTCFs) experienced a large burden of deaths during the COVID-19 pandemic. The study aimed to describe the temporal trends as well as the characteristics and risk factors for mortality among residents and staff who tested positive for SARS-CoV-2 in selected LTCFs across South Africa. Method: We analysed data reported to the DATCOV sentinel surveillance system by 45 LTCFs. Outbreaks in LTCFs were defined as large if more than one-third of residents and staff had been infected or there were more than 20 epidemiologically linked cases. Multivariable logistic regression was used to assess risk factors for mortality amongst LTCF residents. Results: : A total of 2,324 SARS-CoV-2 cases were reported from 5 March 2020 through 31 July 2021; 1,504 (65%) were residents and 820 (35%) staff. Among LTCFs, 6 reported sporadic cases and 39 experienced outbreaks. Of those reporting outbreaks, 10 (26%) reported one and 29 (74%) reported more than one outbreak. There were 48 (66.7%) small outbreaks and 24 (33.3%) large outbreaks reported. There were 30 outbreaks reported in the first wave, 21 in the second wave and 15 in the third wave, with 6 outbreaks reporting between waves. There were 1,259 cases during the first COVID-19 wave, 362 during the second wave, and 299 during the current third wave. The case fatality ratio was 9% (138/1,504) among residents and 0.5% (4/820) among staff. On multivariable analysis, factors associated with SARS-CoV-2 mortality among LTCF residents were age 40-59 years, 60-79 years and ≥80 years compared to <40 years and being a resident in a LTCF in Free State or Northern Cape compared to Western Cape. Compared to pre-wave 1, there was a decreased risk of mortality in wave 1, post-wave 1, wave 2, post-wave 2 and wave 3. Conclusion: The analysis of SARS-CoV-2 cases in sentinel LTCFs in South Africa points to an encouraging trend of decreasing numbers of outbreaks, cases and risk for mortality since the first wave. LTCFs are likely to have learnt from international experience and adopted national protocols, which include improved measures to limit transmission and administer early and appropriate clinical care.

Epidemiology of SARS-CoV-2 infection and SARS-CoV-2 positive hospital admissions among children in South Africa (preprint)

Introduction: We describe epidemiology and outcomes of confirmed SARS-CoV-2 infection and admissions among children <18 years in South Africa, an upper-middle income setting with high inequality. Methods: Laboratory and hospital COVID-19 surveillance data, 28 January - 19 September 2020 was used. Testing rates were calculated as number of tested for SARS-CoV-2 divided by population at risk; test positivity rates were calculated as positive tests divided by total number of tests. In-hospital case fatality ratio (CFR) was calculated based on hospitalized positive admissions with outcome data who died in-hospital and death was judged SARS-CoV-2 related by attending physician. Findings: 315,570 children aged <18 years were tested for SARS-CoV-2; representing 8.9% of all 3,548,738 tests and 1.6% of all children in the country. Of children tested, 46,137 (14.6%) were positive. Children made up 2.9% (n=2,007) of all SARS-CoV-2 positive admissions to sentinel hospitals. Among children, 47 died (2.6% case-fatality). In-hospital deaths were associated with male sex [adjusted odds ratio (aOR) 2.18 (95% confidence intervals (CI) 1.08 - 4.40)] vs female; age <1 year [aOR 4.11 (95% CI 1.08-15.54)], age 10-14 years [aOR 4.20 (95% CI1.07-16.44)], age 15-17 years [aOR 4.86 (95% 1.28 -18.51)] vs age 1-4 years; admission to a public hospital [aOR 5.07(95% 2.01 -12.76)] vs private hospital and ≥1 underlying conditions [aOR 12.09 (95% CI 4.19-34.89)] vs none Conclusions: Children with underlying conditions were at greater risk of severe SARS-CoV-2 outcomes. Children > 10 years and those with underlying conditions should be considered for increased testing and vaccination.

COVID-19 In-Hospital Mortality in South Africa: The Intersection of Communicable and Non-Communicable Chronic Diseases in a High HIV Prevalence Setting (preprint)

Background: The interaction between COVID-19, non-communicable diseases, and chronic infectious diseases such as HIV and tuberculosis (TB) are unclear, particularly in low- and middle-income countries in Africa. We investigated this interaction using a nationally representative hospital surveillance system for laboratory-confirmed COVID-19 hospital admissions in South Africa.Methods: Using DATCOV data, we describe the demographic characteristics, clinical features, and in-hospital mortality among individuals admitted to public and private hospitals with COVID-19 during 5 March to 11 August 2020. Multivariable logistic regression models were used to assess the role of HIV-status and underlying comorbidities on in-hospital COVID-19 mortality.Findings: Hospital admissions peaked at 1,560 admissions per day, in late July. Among the 41,877 individuals admitted with laboratory-confirmed COVID-19, 7,662 (18.3%) died. Comorbidities were documented in 27,555 (65.8%) individuals, most commonly observed were hypertension (36.8%), diabetes (29.6%), obesity (19.7%), and HIV (8.7%); TB was reported in 0.7% of individuals. Increased risk of in-hospital mortality was associated with HIV and TB, as well as other described risk factors for COVID-19, such as increasing age, male sex, non-White race (Black, mixed and Indian race), chronic underlying conditions particularly hypertension, diabetes and obesity. In addition, HIV-infected individuals with immunosuppression had increased risk of mortality (adjusted odds ratio 2.2; 95% confidence interval 1.6-3.1). Among HIV-infected individuals, the prevalence of other comorbidities associated with severe COVID-19 outcomes was 39.9%. The effect of multiple comorbidities on mortality was similar in HIV-infected and -uninfected individuals.Interpretation: These data provide a better understanding of the interaction of non-communicable diseases, chronic infectious diseases like HIV and TB and COVID-19. Increasing age and presence of chronic underlying comorbidities (particularly hypertension and diabetes) are important additional factors associated with COVID-19 mortality in a middle-income African setting and are common among HIV-infected individuals. HIV- and TB-infected individuals, particularly those with additional comorbidities, would benefit from COVID-19 prevention programmes, as well as early referral and treatment.Funding Statement: DATCOV is funded by the National Institute for Communicable Diseases (NICD) and the South African National Government. No additional funding was obtained towards the completion of this analysis and the development of this manuscript.Declaration of Interests: The authors declare that there are no conflicts of interest.Ethics Approval Statement: The Human Research Ethics Committee (Medical), University of the Witwatersrand, approved the project protocol as part of a national surveillance program (M160667). This activity was reviewed by the U.S. Centers for Disease Control and Prevention (CDC) and was conducted consistent with applicable federal law and CDC policy. All personal identifying information was de-linked for our analysis and stored in a secure server.

COVID-19 in-hospital mortality in South Africa: the intersection of communicable and non-communicable chronic diseases in a high HIV prevalence setting (preprint)

Background: The interaction between COVID-19, non-communicable diseases, and chronic infectious diseases such as HIV and tuberculosis (TB) are unclear, particularly in low- and middle-income countries (LMIC) in Africa. We investigated this interaction using a nationally representative hospital surveillance system in South Africa. Methods: A national surveillance system for laboratory-confirmed COVID-19 hospital admissions (DATCOV) was established. Using DATCOV data, we describe the demographic characteristics, clinical features, and in-hospital mortality among individuals admitted to public and private hospitals with COVID-19 during 5 March to 11 August 2020. Multivariable logistic regression models were used to compare individuals who were HIV-infected and HIV-uninfected and determine the factors associated with in-hospital mortality. Findings: Hospital admissions peaked at 1,560 admissions per day, in late July. Among the 41,877 individuals admitted with laboratory-confirmed COVID-19, 7,662 (18.3%) died. Comorbidities were documented in 27,555 (65.8%) individuals, most commonly observed were hypertension (36.8%), diabetes (29.6%), obesity (19.7%), and HIV (8.7%); TB was reported in 0.7% of individuals. Increased risk of in-hospital mortality was associated with HIV and TB, as well as other described risk factors for COVID-19, such as increasing age, male sex, non-White race (Black, mixed and Indian race), chronic underlying conditions particularly hypertension, diabetes and obesity. In addition, HIV-infected individuals with immunosuppression had increased risk of mortality (adjusted odds ratio 2.2; 95% confidence interval 1.6-3.1). Among HIV-infected individuals, the prevalence of other comorbidities associated with severe COVID-19 outcomes was 39.9%. The effect of multiple comorbidities on mortality was similar in HIV-infected and -uninfected individuals. Interpretation: These data provide a better understanding of the interaction of non-communicable diseases, chronic infectious diseases like HIV and TB and COVID-19. Increasing age and presence of chronic underlying comorbidities (particularly hypertension and diabetes) are important additional factors associated with COVID-19 mortality in a middle-income African setting and are common among HIV-infected individuals. HIV- and TB-infected individuals, particularly those with additional comorbidities, would benefit from COVID-19 prevention and treatment programmes.