Beta variant of virus may increase risk for hospitalisation and death

10 July 2021 - 09:39
Nurses prepare vaccination doses in Thembisa, Johannesburg.
Nurses prepare vaccination doses in Thembisa, Johannesburg.
Image: Sebabatso Mosamo

A wide-ranging SA study suggests people infected with the Beta variant of the SARS-CoV-2 virus are at greater risk for hospitalisation and dying from Covid-19.

The observational study, which is due to be presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) and published in The Lancet Global Health, found there was a 31% higher risk of in-hospital deaths during the country’s second wave of infections which were dominated by the Beta variant. 

The Beta variant was first detected in SA in November.

There were 48.1 deaths per 100,000 people in the second wave compared to 24.7 deaths per 100,000 people in the first wave, even after risk factors such as age, sex, race, underlying health issues and weekly Covid-19 hospital admissions were taken into account.

“SA's second wave saw a higher incidence of Covid-19, rapid escalation in hospital admissions, and greater in-hospital deaths”, said Dr Waasila Jassat of the National Institute for Communicable Diseases, the study's lead author.

“While some of this increased mortality can be explained by higher levels of hospitalisations in the second wave tending to be older patients presenting to public sector hospitals with fewer resources, as well as greater pressures on the health system, it is likely that the Beta variant played a key role.”

The study's authors urged caution, however, as the analysis used mortality in the second wave as a proxy for the dominant Beta variant. The study also did not use individual-level sequencing data.

SA's first wave of Covid-19 infections reached its peak in July 2020. The second wave, which peaked in January, was driven by the new variant of the SARS-CoV-2 virus known as 501Y.V2 (Beta).

Research indicated the Beta variant carried a mutation that could allow the virus to spread more easily as well as an additional mutation that could help the virus dodge the human immune system.

“However, there is very little data on the severity of the disease during SA’s second wave dominated by the Beta variant, and few studies offer national data on the factors that may contribute to outcomes for hospitalised patients,” the authors said.

To resolve this, the researchers relied on the DATCOV surveillance system for Covid-19 hospital admissions of all 227,932 patients admitted to 644 public and private hospitals between March 5 2020 and March 27 this year, and compared in-hospital mortality between the two waves.

Some 219,265 patients had a recorded outcome, of whom 51,037 died in hospital, the study found.

The researchers found that compared to the first wave, people hospitalised in the second wave were more likely to be:

  • Older (40-65 or older compared with people under 40);
  • Mixed race than white; and
  • Admitted to public sector hospitals.

“During the second wave, individuals who were black and Indian and had an underlying health condition were less likely to be admitted to hospital than they were during the first wave,” they said.

In weeks where hospital admissions exceeded 8,000, deaths rose by 24% which may have been partly the result of the strain on the health system.

The looming challenge is how to prevent high death rates in the third wave, said co-author Dr Caroline Mudara of the National Health Laboratory Service.

“Key to this will be slowing transmission and spreading out the peak of the epidemic to prevent hospital capacity from being breached, as well as ensuring access to vaccinations.”

The authors noted that the study's findings are observational and other possible factors, such as socioeconomic status and missing data on race and comorbidities, may have skewed the findings.

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