The World Health Organization (WHO) says the Omicron version of COVID-19 has now been reported in 57 countries and is rapidly spreading in South Africa.
But while the WHO’s latest epidemiological report says the delta variant remains dominant, especially in Europe and the Americas, it is still too early to draw any conclusions about Omicron’s global impact.
The European Center for Disease Prevention and Control predicts that the Omicron variant could become the dominant version in Europe within months.
For now, however, the delta variant dominates the cases, and more data are needed to determine the infectivity and severity of Omicron, the WHO says.
“While it seems likely that the development of omicron variants may have an advantage compared to other circulating variants, it is unknown whether this will translate into increased transmissibility,” the WHO report said.
Of the 899,935 Covid-19 test samples sequenced and uploaded to the global COVID database in the last 60 days, 897,886 (99.8%) were confirmed to be delta, while 713 (0.1%) were omicrons.
The WHO report said South Africa recorded 62,021 cases of the variant between November 29 and December 5 – an 111% increase from the previous week.
During the week December 4 – 912 admissions due to Covid-19 saw an 82% increase in hospital admissions in the country as compared to 502 the week before. But it is not yet known how many of these cases were due to Omicron.
Omicron is spreading rapidly in South Africa despite the high rate of past infection with Covid. It is estimated that 60% to 80% of the population has been previously infected. Vaccination rates are low, around 35%.
Data are still too limited to know with certainty whether Omicron changes disease severity. As of 6 December, all 212 confirmed omicron cases in 18 EU countries were classified as asymptomatic or mild.
But the WHO said, “even if the severity is similar or potentially less than that of the delta variant, it is expected that more people will be hospitalized if infected”.
“Further information is needed to fully understand the clinical picture of people infected with the Omicron variant,” the report said.
The WHO said preliminary data suggests that mutations in the oomicron variant may impair the ability of natural immunity to protect against reinfection after infection with the virus.
Omicrons contain mutations that may reduce the ability of natural immunity-generated antibodies to protect against the virus, but further studies are needed to confirm its ability to re-infect previously confirmed cases or those who have been vaccinated. is required.
The report concluded that many questions about the Omicron version remain unanswered, but more information will be revealed in the coming weeks.
Pharmaceutical company Pfizer this week Reported Results Preliminary studies have shown that two doses of its COVID-19 vaccine have a significantly lower ability to neutralize the Omicron variant, and that three doses may be needed.
a Small study from South Africa, which has not yet been peer reviewed, also suggested that antibody neutralization against Omicron is reduced by approximately 40-fold compared to the original virus.
Dr Deborah Kroemer, a Senior Research Fellow at the University of NSW’s Kirby Institute, said in the past, “a trove of preliminary data has emerged showing a decline in immunity against the Omicron variant”.
She said this data came from studies looking at the blood of people who have recovered from COVID-19 and/or have been vaccinated against the disease.
“All studies show lower immunity against Omicron than the original virus strain, although reported droplets vary widely,” she said.
“The estimates we’ve seen of people’s immunity against Omicron range from one-half to one-forty-fifths of the immunity present against the original strain.
“Despite the numbers, it is clear that increased levels of immunity will be required to provide protection against omicrons, and therefore booster shots are now more important than ever to help achieve this.”
The first known laboratory-confirmed case of Omicron was identified in South Africa from a sample collected on 9 November, which was reported to the WHO on 24 November.