Reported new Covid-19 infections dropped by 16% from a week ago, but the number of new cases means the coronavirus is still resurgent.
However, mortality remains “uncoupled” from infections, according to Debbie Bradshaw, a specialist scientist at the Medical Research Council who, with her team, has been tracking excess deaths since early in the pandemic.
“Rather like wave four, the excess deaths appear to be uncoupled from infections. However, it is too early to comment on the sub-lineages [of Omicron],” Bradshaw said.
The number of deaths from natural causes increased during April, particularly among over-60s and “during May, the numbers so far have been 25% higher than the numbers that would have been expected pre-Covid”, she said.
This is low compared with the first wave when excess natural deaths were 110% higher, the second wave (290% higher), the third wave (150%) and the fourth wave (64%).
Waasila Jassat from the National Institute for Communicable Diseases said admissions to hospital had increased countrywide since mid-April, mainly in Gauteng and KwaZulu-Natal.
“This increase is in keeping with the resurgence in cases related to BA.4/BA.5 [sub-variants of Omicron] dominance. The proportion of admissions over total confirmed cases is lower than in previous waves,” she said.
“Severity is defined as a patient admitted to hospital who required oxygen, ventilation, treatment in ICU or died. In this BA.4/BA.5 resurgence admitted patients have lower severity and mortality than in previous waves. However, further data over the next few weeks will be required to make definitive pronouncements of disease severity,” Jassat said.
According to a study published in the latest edition of The Lancet Global Health, SA’s fourth wave was far less severe than previous ones.
The authors, including Jassat and former ministerial advisory committee head Salim Abdool Karim, said there were “approximately three-month periods of low transmission” between each of the first four waves.
The seven-day moving average of daily cases recorded a peak that was higher in each successive wave, and “although the wave duration increased across the first three waves, it declined in the fourth wave”.
Not only was the fourth wave the shortest, it was also the only one in which “a rise in cases was not accompanied by a concomitant rise in hospital admissions”.
Instead, the peak in admissions was lower and of shorter duration than in preceding waves.
The authors found that both disease severity and in-hospital case-fatality ratio were at least twice as high in the three preceding waves than in the Omicron wave.
This was probably due to the variant being less virulent, and immunity from vaccination and previous infections. “The change in disease severity was more marked in adults than in children,” they said.
With the first two years of the pandemic proving to have been the worst, the global health community is assessing the damage done.
New World Health Organisation estimates show that “the full death toll associated directly or indirectly with Covid between January 1 2020 and December 31 2021, is around 14.9-million”.
“These sobering data not only point to the impact of the pandemic but also the need for all countries to invest in more resilient health systems that can sustain essential services during crises, including stronger health information systems,” WHO director-general Tedros Adhanom Ghebreyesus said.
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