Omicron: What we know so far
Rapid spread clearly established but many questions remain about severity and vaccine efficacy
published : 11 Dec 2021 at 16:51
writer: Bloomberg News
A little more than two weeks since the discovery of Omicron, a lot has been learned about the latest coronavirus variant. A lot remains to be discovered.
Early data from South Africa, the epicentre so far, shows that the virus appears to spread far faster than earlier strains but also doesn’t appear to be causing severe disease.
Nothing is definitive yet, so the world is still somewhat in the dark. With Omicron cases doubling every few days in the United Kingdom, policymakers and investors are grasping at any clues; the spread in Britain could be a harbinger of things to come across Europe and the United States.
Health officials had been moving toward the end of year with a little hope that the Covid era was shifting into a newer, more manageable phase.
But now it’s not clear yet if 2022 will succeed where 2021 has been defeated: suppress the spread of the virus enough to stop the rolling infection waves and finally end social restrictions.
Initial laboratory studies indicate Omicron is much more transmissible than even Delta, the strain that spread rapidly across the globe, filling hospitals and boosting death rates. They also show that it can infect the vaccinated or those who have already been ill with Covid-19.
What’s not known yet is how it developed, and whether it will cause more severe disease in countries with older populations than South Africa. Also unclear is whether it can out-compete Delta in places where that version is dominant now, such as Europe and the US.
New cases in South Africa, following a severe Delta-led third wave, were negligible for weeks before the unwelcome emergence of Omicron.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said this week that information so far points to a less severe mutation.
“The big challenge we’re going to have is confirming that over the next two weeks,” he said on his Osterhom Update podcast. “From there, then we can figure out what does it mean in terms of the next leg of the pandemic for the world.”
This is what we know so far:
How fast is Omicron spreading?
In Gauteng, where South Africa’s outbreak is currently centred, the reproduction rate — how fast the virus spreads — is over 3. That’s the highest it’s been and means that every infected person on average infects three more.
Cases in South Africa are rising at a near-record pace, and the rate of increase has outstripped the three earlier waves the country experienced.
Omicron is 4.2 times more transmissible than Delta, according to a study in Japan.
The UK says the new strain is growing much faster than Delta, and it expects Omicron to become the dominant variant by the middle of December, accounting for more than half of new cases. On Friday, the UK reported almost 58,200 new Covid cases overall.
How severe are the infections?
With the outbreak just a few weeks old, it’s too early to tell definitively, but doctors have reported patients with fatigue and headaches and little more. That’s a big contrast to Delta’s racing pulse rates and respiratory problems.
South Africa’s three biggest private hospital operators say cases are much milder than in earlier waves. There are few people on oxygen or ventilators and only a slight uptick in deaths.
Currently there are about 5,000 people with Covid in South African hospitals, a quarter of the peaks seen in the previous two waves.
Does it affect children differently from earlier variants?
Initial hospital admissions in South Africa saw a higher number of children under the age of 5 than previously.
Still, most only stay in hospital for a short time, and Health Minister Joe Phaahla says there are no reports of respiratory complications.
Do vaccines work?
Yes and no.
The Africa Health Resource Institute was the first to isolate the virus and test it against the Pfizer shot. Omicron is able to largely, but not completely, evade the antibodies generated in response to the inoculation, the research showed. Pfizer’s own study backed that up.
The UK said Friday that two shots from AstraZeneca or Pfizer/BioNTech provided much less protection against symptomatic infection with Omicron, compared with the Delta strain. But a booster lifted that to 70% to 75% in the early days after the shot, according to preliminary data from a small study.
Data from South African hospitals in the municipal area of Tshwane presented on Dec 3 showed that 68% of coronavirus hospital admissions were in people under age 40. That compares with individuals over 50 accounting for 66.1% of hospitalisations during the first weeks of the third wave. South Africans over 60 are about twice as likely to have been vaccinated than those under 34.
Where did it come from?
There are three theories:
The first is the virus mutated in someone who was immunosuppressed and harbored the pathogen for a long time, allowing it to change and then infect others. South Africa has 8.2 million people carrying HIV, which causes the immune system disease Aids.
The second is that the coronavirus crossed back into an animal, mutated, and then reinfected a human.
The third is that it developed by circulating somewhere with little genetic sequencing and not much access to healthcare. It was then picked up in South Africa, where sequencing of samples is comparatively common. Some of the world’s weakest health systems are in Africa.
So where to from here?
Depends who you listen to.
Richard Friedland, the chief executive officer of Netcare Ltd, South Africa’s biggest private hospital group, is optimistic.
“I actually think there is a silver lining here and this may signal the end of Covid-19, with it attenuating itself to such an extent that it’s highly contagious, but doesn’t cause severe disease,” he said. “It’s early days, but I’m less panicked. It feels different to me on the ground.”
The World Health Organization is remaining cautious for now given so many unknowns, and the concern that any variant is a risk.
“If they’re allowed to spread unchecked, even though they’re not individually more virulent or more lethal, they generate more cases, put pressure on the health system and more people die,” said Mike Ryan, executive director of the WHO emergencies programme.
“We should hope for the best outcome, but in this particular case, hope is not a strategy. We need to be very careful on making any final determinations on severity.”