Omicron less likely to result in Covid-19 hospitalization than delta: Study


LONDON: 23, DECEMBER, 2021: The omicron coronavirus variant may be milder than the delta version, the two new UK studies provide some early hints.
Still, the new studies released Wednesday seem to bolster earlier research that suggests omicron may not be as harmful as the delta variant, said Manuel Ascano Jr., a Vanderbilt University biochemist who studies viruses.
He said "Cautious optimism is perhaps the best way to look at this."
An analysis from the Imperial College London COVID-19 response team estimated hospitalization risks for omicron cases in England, finding people infected with the variant are around 20% less likely to go to the hospital at all than those infected with the delta variant, and 40% less likely to be hospitalized for a night or more.
That analysis included all cases of COVID-19 confirmed by PCR tests in England in the first half of December in which the variant could be identified: 56,000 cases of omicron and 269,000 cases of delta.
A separate study out of Scotland, by scientists at the University of Edinburgh and other experts, suggested the risk of hospitalization was two-thirds less with omicron than delta. But that study pointed out that the nearly 24,000 omicron cases in Scotland were predominantly among younger adults ages 20 to 39. Younger people are much less likely to develop severe cases of COVID-19.
“This national investigation is one of the first to show that omicron is less likely to result in COVID-19 hospitalization than delta,” researchers wrote. While the findings are early observations, “they are encouraging,” the authors wrote.
Matthew Binnicker, director of clinical virology at Mayo Clinic in Rochester, Minnesota, said that in the Scottish study, the percentage of younger people was almost twice as high for the omicron group compared with the delta group, and that “could have biased the conclusions to less severe outcomes caused by omicron.”
He nonetheless said the data were interesting and suggest omicron might lead to less severe disease. But he added: “It’s important to emphasize that if omicron has a much higher transmission rate compared to delta, the absolute number of people requiring hospitalization might still increase, despite less severe disease in most cases.”
It is to be noted that, on Decemeber 13, the WHO said the Omicron coronavirus variant is more transmissible than the Delta strain and reduces vaccine efficacy but causes mild illness.
South Africa's discovery of Omicron, which has a large number of mutations, last month prompted countries around the world to impose travel bans on southern African countries and reintroduce domestic restrictions in a bid to prevent spread.
South Africa reported Omicron to the WHO on November 24. Vaccine manufacturers Pfizer/BioNTech last week said three doses of their jabs were still effective against Omicron. The WHO said Omicron had spread to 63 countries as of December 9.
Early evidence suggests Omicron causes "a reduction in vaccine efficacy against infection and transmission", the WHO said in a technical brief.
"Given the current available data, it is likely that Omicron will outpace the Delta variant where community transmission occurs," it added.
Earlier, on December 4, the World Health Organization (WHO) on Friday has said that the omicron variant has been detected in 38 countries but no deaths have yet been reported.
The WHO said it had still not seen any reports of deaths related to omicron, but the new variant’s spread has led to warnings that it could cause more than half of Europe’s Covid cases in the next few months.
It could take weeks to determine how infectious the variant is, whether it causes more severe illness and how effective treatments and vaccines are against it, the WHO warned.
The Organization's emergencies director Michael Ryan said that "We're going to get the answers that everybody out there needs."
On the other hand, the International Monetary Fund (IMF) head Kristalina Georgieva stated that "The new variant could also slow global economic recovery, just as the Delta strain did."
"Even before the arrival of this new variant, we were concerned that the recovery, while it continues, is losing somewhat momentum," she said, adding that, "A new variant that may spread very rapidly can dent confidence."
A preliminary study by researchers in South Africa, where the omicron was first reported on November 24, suggests "it is three times more likely to cause reinfections compared to the Delta or Beta strains."
Red Cross chief Francesca Rocca said that "The emergence of omicron was the “ultimate evidence” of the danger of unequal global vaccination rates."
"The incidence in those under-fives is now second-highest, and second only to the incidence in those over 60," said Wassila Jassat from the National Institute for Communicable Diseases.
The Hawaii Health Department said, "In the US, two cases involved residents with no recent international travel history — showing omicron is already circulating inside the country."
"This is a case of community spread," the Department said. (04)

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