A major South African study suggests that Omicron-eating people are 81% less likely to need hospitalization than Delta-eating ones.
The real-world analysis, of more than 160,000 people, comes ahead of a similar UK Government report believed to show Britons are also less likely to be severely ill with the variant.
Omicron also had a lower severity rate than the Delta wave that swept through the country in April-November. There were 70% fewer patients who needed mechanical ventilation or admitted to ICU.
The researchers found that Omicron admissions to Delta were almost identical in recent months. This could have been due to built up immunity.
South African physicians insist for weeks Omicron is more milder than it was when they raised the alarm on November 24, and accuse the UK of being panicked about Omicron.
However, the South African National Institute for Communicable Diseases, (NICD) researchers who conducted the study said that it doesn’t yet answer whether Omicron or Delta is intrinsically more weak than Omicron.
Researchers concluded that it was difficult to determine the contribution of the high level of immunity in the past population versus the intrinsically lower virulence due to the lower degree of disease severity.
The most important thing in keeping patients out hospital is the built-up immunity to the three preceding waves of this virus.
South Africans could have been vaccinated with Covid up to 70% of the time. Only 25% are double-vaccinated and boosters are not yet widely available.
These findings raise hopes that the UK will also be facing a milder tsunami. The UK has 75% of its population double-jabbed, and almost half of it boosted.
Omicron cases from South Africa dropped yesterday for the fourth straight day. However, the daily Omicron cases for the UK have remained steady at approximately 90,000 over six days.
South Africa’s hospital admissions have dropped by five percent in one week. They are now at or below 400 per daily, with an average of around 300 per day. The UK has a hospital rate of around 900 per person, which is mostly unchanged since the end of summer.
This is despite the fact that the Government has warned of 1 million Britons being at risk for contracting the virus every day by year’s end.
Paul Hunter from the University of East Anglia is an expert on infectious diseases and described the South African study’s importance. He also said that it was the first pre-print study of Omicron severity to be properly done.
However, Professor Hunter stated that its biggest weakness was the way it compared Omicron data of one period to Delta data from an older period.
He stated that Omicron cases were more likely to be admitted to hospital than Delta cases. However, it was not clear if this could have been due to differences in virus virulence, or a higher level of immunity among the population in November.
“To some extent, this doesn’t matter to patients who care only that they don’t get very sick.” However, it’s important to be able to better understand how health services will respond to these pressures.
A group of scientists at the National Institute for Communicable Diseases, (NICD), and top universities such as University of KwaZulu-Natal and University of the Witwatersrand performed the analysis.
Data were sourced from four sources. These included data from national COVID-19 cases reported to the NICD and data from one of the large private sector laboratories. Genome data was also used to analyze clinical specimens from both private and public diagnostic centers across the country sent to the NICD.
The researchers compared Omicron infection data from October and November to data regarding Delta infections, which was all taken in South Africa.
Omicron was determined to have occurred in a case if it failed to detect a part of the virus’ cells. This is a sign that Omicron has been extensively mutational and there are high levels of Omicron within the specimen.
If a patient is admitted to hospital in the seven- or 21-day period after testing positive, a hospitalisation can be linked to a positive case.
Patients with severe diseases are those who have been admitted to ICU or require mechanical ventilation. They also receive oxygen therapy and fluid leakage into the lungs.
This study has been published preprint on the medRxiv website. The authors found that 2,61% (2.5%) of 10,547 Omicron patients identified between October 1, and November 30, were admitted into hospital.
For comparison: Of the 948 non Omicron cases during the same time – nearly all of which would be Delta which was behind 95 percent of Omicron’s cases – only 121 were admitted (12.8%)
The researchers found that Omicron-infected people had an 80 percent lower chance of needing hospitalization after accounting for all other factors.
The illness severity was identical among patients hospitalized with each strain over the nine week period. Only 317 out of 382 (83%) were discharged prior to December 21.
The scientists did however find that Omicron patient were more likely to be hospitalized than Delta ones earlier in the year.
1.734 South Africans have been admitted since the outbreak of the pandemic. Their test results were either Alpha, Beta or Delta.
Omicron infection rates were also higher than those of Delta patients, confirming recent research and evidence that Omicron is more transmissible.
According to the researchers, around 7/10 South Africans have been infected in Covid since November. Omicon also revealed that 25% of South Africans are double-jabbed.
Experts said it is difficult to determine how vaccines and previous infections contribute to Omicron’s high immunity to hospitalisation and serious illness. They also discussed how Omicron’s severity is affected.
Researchers found that there was no significant difference in severity between Omicron- and Delta patients who were hospitalized in the past two months. This suggests that Omicron’s reduced severity may be due in part to high immunity levels in the population, possibly from previous infections or vaccines.
Officials who examined 78,000 Omicron patients in the last month discovered that the likelihood of being hospitalized was five times lower than for Delta (in blue) and 29% lower than for the original Omicron virus (dark). Omicron in blue and South African’s original ‘Beta’ variant in dark blue are shown. The new outbreak caused a 20% increase in hospital admissions for children with complications, even though the number of cases was still small.
As a crude rate, Omicron is currently causing a third fewer hospital admissions than Delta did during its entire wave — 38 admissions per 1,000 Omicron cases, compared to 101 per 1,000 for Delta
The team stated that the high immunity of our population (due prior to infection or vaccination) could be beneficial in preventing severe diseases.
Scientists cautioned that their findings should not be taken as gospel. The study was done early in Omicron waves, when patients with milder symptoms are more likely to receive admission. It also only considered individuals whose information was collected during their stay. This may have biased the results towards those with shorter stays.
Paul Hunter (a University of East Anglia professor of medicine) said that the results are the first proper study to assess Omicron’s severity in relation to Delta.
He said that its biggest weakness was the way it compares Omicron data from one time with Delta data from a different period.
Dr Hunter said that Omicron cases were more likely to be admitted to hospital than Delta cases. However, this cannot be attributed to differences in virus virulence.
“But, to a certain degree this is not important for the patient who just cares about not getting very sick.” However, it’s important to be able to better understand how health services will respond to these pressures.
This is after an independent study that looked at 78,000 Omicron patients in South Africa and found that the likelihood of being hospitalized was 55% lower than for Delta, 29% lower than for the original Omicron virus.
As a crude rate, Omicron is led to a third fewer hospital admissions than Delta did during its entire wave — 38 admissions per 1,000 Omicron cases compared to 101 per 1,000 for Delta.
Two doses of Pfizer’s vaccine provided 70 percent protection against Omicron-related hospitalizations or deaths, as compared with 93 percent for Delta.
Although this provides more protection than scientists originally believed, 30 percent of those still at risk for severe Omicron Disease, which is four times the number found in Delta, are still vulnerable.
The country’s case number has risen dramatically due to the fact that a two-dose Pfizer regimen did not provide 33% immunity against Omicron infection.