The report, which analysed symptoms and severity of patients with Omicron from Tshwane an epicentre of the outbreak also showed a marked difference in patient condition from that of previous waves seen in the two years of the pandemic.

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Between November 14 and 29, a sharp rise was observed in admissions at the Steve Biko Academic and Tshwane District Hospitals (SBAH/TDH) Complex. Of 166 new admissions, 42 patients are currently in the COVID wards. And most patients had another medical, surgical or obstetric reason, and SARS-CoV-2 has been an incidental finding in them.

"The main observation that we have made over the last two weeks is that the majority of patients in the COVID wards have not been oxygen-dependent," according to Dr Fareed Abdullah, the Director of the Office of AIDS and TB Research at the South African Medical Research Council (SAMRC).

"The majority of hospital admissions are for diagnoses unrelated to COVID-19. The SARS-CoV-2 positivity is an incidental finding in these patients and is largely driven by hospital policy requiring testing of all patients requiring admission to the hospital," he added.

Of the 42 patients in the ward, 29 (70 per cent) were not oxygen-dependent and the "patients were saturating well on room air and did not present with any respiratory symptom. This is a picture that has not been seen in previous waves. The numbers of patients in high care on double oxygen, High Flow Nasal Oxygen or non-invasive ventilation (NIV) were noticeably higher in previous waves," Abdullah said.

Further, the report revealed that the age profile differed markedly from hospital admissions among COVID patients seen in the previous 18 months. No fewer than 80 per cent of admissions were below the age of 50 years and about 19 per cent were children aged 0-9 years. The highest number of admissions was in the age group 30-39 years, making up 28 per cent of the total, the report said.

As Omicron is found to have more than 30 mutations in its spike protein, the main concern over its outbreak is whether disease severity is similar, milder or more severe than with the other variants. There were 10 deaths in the SBAH/TDH cohort in the past two weeks, making up 6.6 per cent of the 166 admissions.

But it hasn't been determined that Omicron was the cause. There were no COVID related deaths among 34 admissions in the paediatric COVID wards over the last two weeks.

The report showed an "absence of any significant increase in in-hospital deaths in relation to the dramatic rise in the case rate for the Gauteng Province as a whole". However, "the trend will become clearer over the next few weeks," Abdullah said.

Moreover, there were only 2 patients in the COVID ICU in the last 14 days, neither of whom had a primary diagnosis of COVID pneumonia, showing less severity of Omicron. Sixty-three patients were admitted to high care, but our anecdotal information is that the majority of high care admissions were for a diagnosis other than COVID. Detailed study reports are awaited.

"Another significant early finding in this analysis is the much shorter average length of stay of 2.8 days for SARS-CoV-2 positive patients admitted to the COVID wards over the last two weeks compared to an average length of stay of 8.5 days for the past 18 months," Abdullah said.

"The relatively low number of COVID-19 pneumonia hospitalisations in the general, high care and ICU wards constitutes a very different picture compared to the beginning of previous waves. However, the information represents just the first two weeks of the Omicron wave in Tshwane and the "clinical profile of admitted patients could change significantly over the next two weeks," Abdullah said.