Lancet preprint: Clinical Severity of COVID-19 Patients Admitted to Hospitals in Gauteng, South Africa During the Omicron-Dominant Fourth Wave

[sharon sanders]

Clinical Severity of COVID-19 Patients Admitted to Hospitals in Gauteng, South Africa During the Omicron-Dominant Fourth Wave

19 Pages Posted: 29 Dec 2021
Waasila Jassat


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Salim Abdool Karim


University of KwaZulu-Natal - Centre for the AIDS Programme of Research in South Africa (CAPRISA)
Caroline Mudara


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Richard Welch


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Lovelyn Ozougwu


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Michelle Groome


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases; London School of Hygiene and Tropical Medicine - MRC International Statistics and Epidemiology Group
Nevashan Govender


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Anne von Gottberg


National Health Laboratory Services - Centre for Respiratory Diseases and Meningitis; University of the Witwatersrand - School of Pathology
Nicole Wolter


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
DATCOV Author Group

Lucille Blumberg


National Health Laboratory Services (NHLS) - National Institute for Communicable Diseases
Cheryl Cohen


National Health Laboratory Services (NHLS) - Centre for Respiratory Diseases and Meningitis; University of the Witwatersrand - School of Public Health

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Abstract


Background: As Omicron became the dominant variant in South Africa, little is known about the severity of its clinical presentation. We describe the clinical severity of patients hospitalised with SARS-CoV-2 infection during the first four weeks of the Omicron-dominated fourth wave and compare this to the first four weeks of the Betadominated second and Delta-dominated third waves in Gauteng Province.

Methods: Polymerase chain reaction and antigen positive SARS-CoV-2 case data were collated daily from laboratory reports. Data on hospital admissions were collected through an active surveillance programme established specifically for COVID-19. In addition to descriptive statistics, post-imputation random effect multivariable logistic regression models were used to compare disease severity in the three wave periods. Severe disease was defined as one or more of acute respiratory distress, supplemental oxygen, mechanical ventilation, high/intensive care or death.

Results: There were 41,046, 33,423, and 133,551 SARS-CoV-2 cases in the second, third and fourth waves respectively. About 4.9% of cases were admitted to hospital during the fourth wave compared to 18.9% and 13.7% during the second and third waves (p<0.001). During the fourth wave, 28.8% of admissions were severe disease compared to 60.1% and 66.9% in the second and third waves (p<0.001). Admitted patients in the omicron-dominated fourth wave were 73% less likely to have severe disease than patients admitted during the delta-dominated third wave (adjusted odds ratio [aOR] 0.27, 95% confidence interval [CI] 0.25-0.31).

Conclusion: The proportion of cases admitted was lower and those admitted were less severe during the first four weeks of the Omicron-dominated fourth wave in Gauteng province of South Africa. Since any combination of a less-virulent virus, comorbidities, high immunity from prior infection(s) or vaccination may be important contributors to this clinical presentation, care should be taken in extrapolating this to other populations with different co-morbidity profiles, prevalence of prior infection and vaccination coverage.

Funding Information: DATCOV as a national surveillance system, 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.


https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3996320

 

[sharon sanders]

Interpretation of above paper by:

Mia Malan



1h, 16 tweets, 12 min read Bookmark Save as PDF My Authors
[Thread] JUST IN:

How sick did #COVID19 patients in SA get during Gauteng's #Omicron wave?

NEW @TheLancet preprint: bit.ly/3FJj6mA (via Waasila Jasat, @ProfAbdoolKarim et al.)

Clinical Severity of COVID-19 Patients Admitted to Hospitals in Gauteng, South Africa During the Omicron-Dominant Fourth Wavehttps://bit.ly/3FJj6mA
2. Why did study authors look @ Gauteng + not the entire SA?
1. SA's #Omicron outbreak started in Gauteng, so there's data 4 a longer period than other provinces
2. They looked @ the 1st 4 weeks of #Omicron + compared it to the same periods for Wave 2 (Beta), Wave 3 (#Delta)

3. From when to when were the 1 month periods of the waves?
- Wave 2 (Beta): 29 Nov-26 Dec 2020
- Wave 3 (#Delta): 2 May-29 May 2021
- Wave 4 (#Omicron): 14 Nov-11 Dec 2021
4. How many reported #COVID19 cases (so how many people tested positive) during the 1st month of each wave in Gauteng?

- Wave 2 (Beta): 41,046
- Wave 3 (#Delta): 33,423
- Wave 4 (#Omicron): 133,551
5. Which % of people who tested + for #COVID19 got admitted to hospital in the different waves?
- Wave 2 (Beta): 18.9% (7,774/41,046)
- Wave 3 (#Delta): 13.7% (4,574/33,423)
- Wave 4 (#Omicron): 4.9% (6,510/133,551)
6. Which % of #COVID19 hospital patients had severe disease?
- Wave 2 (Beta): 60.1% (4,672/7,774)
- Wave 3 (#Delta): 66.9% (3,058/4,574)
- Wave 4 (#Omicron): 28.8% (1,276/4,438) [2,072/ 6,510 patients = a not a documented hospital outcome when the study = submitted]
7. What counts for severe disease?
- Acute respiratory distress
- Oxygen supplementation
- Ventilation
- Intensive care unit admission
- Death

8. % of #COVID19 patients needing supplemental oxygen:
- Wave 2 (Beta): 39.4% (3,063/7,774)
- Wave 3 (#Delta): 48.8% (2,231/4,574)
- Wave 4 (#Omicron): 19.7% (875/4,438)
9. Median hospital stay:
- Wave 2 (Beta): 7 days
- Wave 3 (#Delta): 8 days
- Wave 4 (#Omicron): 4 days
10. % of cases (of total admissions) admitted among children + teens below 20 years:
- Wave 2 (Beta): 3.9% (306/7,774)
- Wave 3 (#Delta): 3.5% (161/4,574)
- Wave 4 (#Omicron): 17.7% (1,151/6,510)
11. % of hospitalised patients younger than 20 years with severe disease:
- Wave 2 (Beta): 22.5% (69/306)
- Wave 3 (#Delta): 23.0% (37/161)
- Wave 4 (#Omicron): 20.4% (172/844)
12. What does the data tell us?

Admitted patients in the 1st month of SA's #Omicron (4th) wave were 73% less likely to have severe disease than patients admitted during the 1st month of the Beta and #Delta waves.

13. Great explanation via @ProfAbdoolKarim:
1. #Omicron caused 4x more infections than #Delta in the 1st 4 wks of each GP wave
2. But #Omicron's hospital admission rate = +/- a quarter of #Delta's. So Omicron leads to almost the same nr of Delta admissions but in a shorter time.
14. #Omicron admissions don't strain the health system to same extent as #Delta admissions because Omicron leads to severe disease 73% less often than Delta (after adjustment).
15. NB: The study can't tell u how much of #Omicron's milder disease effect = is due to a less virulent virus, vaccination and/or past immunity (especially vaccination in those with past infection).

@ProfAbdoolKarim = likely all 3 play a role (probs in this order of importance).
16. As any combination of a less virulent virus, co-
morbidities, high immunity from prior infection(s)/vax may be contributors 2 #Omicron's milder disease, this study's results = not necessarily hold true 4 countries with diff co-morbidity profiles, prior infection/vax coverage.
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