Outcomes of laboratory-confirmed SARS-CoV-2 infection during resurgence driven by Omicron lineages BA.4 and BA.5 compared with previous waves in the Western Cape Province, South Africa.

OBJECTIVE: We aimed to compare clinical severity of Omicron BA.4/BA.5 infection with BA.1 and earlier variant infections among laboratory-confirmed SARS-CoV-2 cases in the Western Cape, South Africa, using timing of infection to infer the lineage/variant causing infection. METHODS: We included public sector patients aged ≥20 years with laboratory-confirmed COVID-19 between 1-21 May 2022 (BA.4/BA.5 wave) and equivalent prior wave periods. We compared the risk between waves of (i) death and (ii) severe hospitalization/death (all within 21 days of diagnosis) using Cox regression adjusted for demographics, comorbidities, admission pressure, vaccination and prior infection. RESULTS: Among 3,793 patients from the BA.4/BA.5 wave and 190,836 patients from previous waves the risk of severe hospitalization/death was similar in the BA.4/BA.5 and BA.1 waves (adjusted hazard ratio (aHR) 1.12; 95% confidence interval (CI) 0.93; 1.34). Both Omicron waves had lower risk of severe outcomes than previous waves. Prior infection (aHR 0.29, 95% CI 0.24; 0.36) and vaccination (aHR 0.17; 95% CI 0.07; 0.40 for at least 3 doses vs. no vaccine) were protective. CONCLUSION: Disease severity was similar amongst diagnosed COVID-19 cases in the BA.4/BA.5 and BA.1 periods in the context of growing immunity against SARS-CoV-2 due to prior infection and vaccination, both of which were strongly protective.

Outcomes of laboratory-confirmed SARS-CoV-2 infection in the Omicron-driven fourth wave compared with previous waves in the Western Cape Province, South Africa.

OBJECTIVES: The objective was to compare COVID-19 outcomes in the Omicron-driven fourth wave with prior waves in the Western Cape, assess the contribution of undiagnosed prior infection to differences in outcomes in a context of high seroprevalence due to prior infection and determine whether protection against severe disease conferred by prior infection and/or vaccination was maintained. METHODS: In this cohort study, we included public sector patients aged ≥20 years with a laboratory-confirmed COVID-19 diagnosis between 14 November and 11 December 2021 (wave four) and equivalent prior wave periods. We compared the risk between waves of the following outcomes using Cox regression: death, severe hospitalisation or death and any hospitalisation or death (all ≤14 days after diagnosis) adjusted for age, sex, comorbidities, geography, vaccination and prior infection. RESULTS: We included 5144 patients from wave four and 11,609 from prior waves. The risk of all outcomes was lower in wave four compared to the Delta-driven wave three (adjusted hazard ratio (aHR) [95% confidence interval (CI)] for death 0.27 [0.19; 0.38]. Risk reduction was lower when adjusting for vaccination and prior diagnosed infection (aHR: 0.41, 95% CI: 0.29; 0.59) and reduced further when accounting for unascertained prior infections (aHR: 0.72). Vaccine protection was maintained in wave four (aHR for outcome of death: 0.24; 95% CI: 0.10; 0.58). CONCLUSIONS: In the Omicron-driven wave, severe COVID-19 outcomes were reduced mostly due to protection conferred by prior infection and/or vaccination, but intrinsically reduced virulence may account for a modest reduction in risk of severe hospitalisation or death compared to the Delta-driven wave.

Evaluation of patient characteristics, management and outcomes for COVID-19 at district hospitals in the Western Cape, South Africa: descriptive observational study.

OBJECTIVES: To describe the characteristics, clinical management and outcomes of patients with COVID-19 at district hospitals. DESIGN: A descriptive observational cross-sectional study. SETTING: District hospitals (4 in metro and 4 in rural health services) in the Western Cape, South Africa. District hospitals were small (<150 beds) and led by family physicians. PARTICIPANTS: All patients who presented to the hospitals' emergency centre and who tested positive for COVID-19 between March and June 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: Source of referral, presenting symptoms, demographics, comorbidities, clinical assessment and management, laboratory turnaround time, clinical outcomes, factors related to mortality, length of stay and location. RESULTS: 1376 patients (73.9% metro, 26.1% rural). Mean age 46.3 years (SD 16.3), 58.5% females. The majority were self-referred (71%) and had comorbidities (67%): hypertension (41%), type 2 diabetes (25%), HIV (14%) and overweight/obesity (19%). Assessment of COVID-19 was mild (49%), moderate (18%) and severe (24%). Test turnaround time (median 3.0 days (IQR 2.0-5.0 days)) was longer than length of stay (median 2.0 day (IQR 2.0-3.0)). The most common treatment was oxygen (41%) and only 0.8% were intubated and ventilated. Overall mortality was 11%. Most were discharged home (60%) and only 9% transferred to higher levels of care. Increasing age (OR 1.06 (95% CI 1.04 to 1.07)), male (OR 2.02 (95% CI 1.37 to 2.98)), overweight/obesity (OR 1.58 (95% CI 1.02 to 2.46)), type 2 diabetes (OR 1.84 (95% CI 1.24 to 2.73)), HIV (OR 3.41 (95% CI 2.06 to 5.65)), chronic kidney disease (OR 5.16 (95% CI 2.82 to 9.43)) were significantly linked with mortality (p<0.05). Pulmonary diseases (tuberculosis (TB), asthma, chronic obstructive pulmonary disease, post-TB structural lung disease) were not associated with increased mortality. CONCLUSION: District hospitals supported primary care and shielded tertiary hospitals. Patients had high levels of comorbidities and similar clinical pictures to that reported elsewhere. Most patients were treated as people under investigation. Mortality was comparable to similar settings and risk factors identified.