The latest numbers

Omicron has now been detected in 57 countries, but it is growing the fastest in South Africa and the UK.

South Africa: New cases are rising more quickly in SA than previous waves—and the R number is over 3. The reproduction number indicates how many people one person can infect. The country recorded a new high of 37,875 new cases on Sunday—a dramatic overnight surge from 17,154 the previous day. The latest and most prominent person to report contracting Covid: South African president Cyril Ramaphosa. 

The UK: Cases caused by the variant are doubling every 2.2 days—and is outpacing the spread of South Africa, where it is doubling every three days. Some experts predict that Omicron cases will hit 64,000 a day in two weeks's time at the current rate in the UK. The government has raised the alert level to four—the highest being five. And a new study suggests that the country will see a new Omicron-fuelled wave in January—and anywhere between 20.9 million to 34.2 million cases between December and April, 2022.

India: has reported 38 Omicron cases. Maharashtra has the highest number—including a 1.5-year-old toddler and three-year-old child. None of the cases appear serious.

Is it easier to detect?

Yes. The WHO recently recommended something called a ‘S-gene target failure’ test to detect the presence of Omicron—so we don’t have to wait for genome sequencing, which takes much longer. This is basically a version of the RT-PCR test—which looks at the RNA material in the virus. If this S-gene is missing, then it indicates the variant is Omicron.

A big ‘but’: As Scroll notes, only one company in the world makes the S-gene failure test recommended by the WHO. And it can manufacture 25 million test kits per week worldwide. So if Omicron spreads, this could turn into a bottleneck. Potential good news: the Indian Council of Medical Research just announced that it has developed its own test that can detect Omicron in two hours. But it has not been tested in the real world as yet. 

Also, about those two Omicrons: Scientists have identified two sub-lineages of the variant BA.1 and BA.2. All this means is that BA.2 is missing some of the mutations of BA.1—and has ones that are different. The problem is that BA.2 doesn’t have the mutation which allows us to detect the variant using the S-gene failure test. Genome sequencing is required to spot it.

Is it more infectious?

Most likely, yes. The evidence is still preliminary but most experts point to the fact that Omicron has been able to outcompete Delta in South Africa—emerging as the dominant variant. Here’s what the data shows:

• A recent Japanese study found that Omicron is 4.2 times more transmissible than Delta. Omicron cases are doubling every two or three days—a much shorter time period compared to Delta. 
• Also: British researchers found that Omicron is 3.2 times more likely to cause an infection within a household than Delta. 
• Based on the rise in Covid cases and on sequencing data, experts estimate that Omicron can infect three to six times as many people as Delta, over the same time period. 

Is it less severe?

Maybe. It is far too early to celebrate, but most indications so far are that Omicron does not cause severe illness. Here’s what evidence we have:

• Doctors so far have reported fatigue and headaches as primary symptoms—unlike Delta which causes racing pulse rates and respiratory problems.
• In South Africa, the spike in cases has not been accompanied by a similar surge in hospitalisations. And initial data shows that those who were hospitalised did not need supplemental oxygen. So it may not cause severe respiratory illness unlike Delta.

As for India: Some experts are already predicting that an Omicron wave will be milder—with most remaining asymptomatic—because the majority of the population has already been exposed to the virus: "India has the advantage of a very high rate of 'seropositivity' of 70-80%, and in big cities more than 90% people already have antibodies.” 

A big ‘but’: Most of the South African data involves younger people and children. And researchers caution that “the clinical profile of admitted patients could change significantly over the next two weeks, by which time we can draw conclusions about the severity of disease with greater precision.”

Key quote to note: None of this is reason to become complacent—or assume that more virulent variants won’t emerge. As one evolutionary biologist warned on Twitter:

“One thing to stress is that viruses do not inevitably evolve to become less virulent over time. If this has happened with omicron—and it's too early to tell whether it has—it would be a matter of good fortune.”

Do vaccines work?

We don’t really know yet—but there is some indication that Omicron can escape vaccine immunity. A small, preliminary study looked at 12 people who had received the Pfizer vaccine—of which six already previously had Covid. And it showed a 41-fold drop in their bodies’ ability to neutralize the variant. One virologist said: "We seem to see a drastic reduction in neutralizing activity, far more than with previous variants.”

Enter, the booster: The same research also showed that those who had been infected before fared much better—which indicates booster shots may be effective. This confirms the findings of a German study that indicates a third shot of Pfizer or Moderna makes the vaccines as effective in protecting against Omicron as they are with Delta. Data out of Israel also confirms the efficacy of a third Pfizer booster shot.

But what about Covishield/Covaxin? A UK study revealed very poor results: “the level of neutralising antibodies induced by two doses of the AstraZeneca vaccine dropped in the presence of an infection by the omicron variant to below the researchers’ minimum detection threshold.” To reiterate, they couldn’t even detect the antibodies triggered by Omicron. We don’t know much about how it performs against Covaxin as the government has just about started growing the virus in labs—to test it against our vaccines.

Point to note: A number of Indian experts are sceptical about the South African study mainly because it looked at the Pfizer vaccine—which uses mRNA technology unlike the vaccines in India. Also: Others claim that Indians have stronger ‘hybrid immunity’—as in many have been vaccinated and been exposed to the virus in the past.

Boosters for Indians? The ICMR is not keen on recommending booster shots—as the priority is to first ensure that most of the population is vaccinated. At the very least, vaccines are still proven to reduce the severity of Covid. 

More importantly: Even if the government does greenlight boosters, the panel of top government advisers are insisting you take a different vaccine than your original two doses. In other words, if you took two jabs of Covishield, then the government will insist your booster be either Covaxin or Sputnik—and vice versa. Of course, you can also pick from a number of new vaccines that will be rolled out in the coming months—including Biological E’s Corbevax, the Indian version of Novavax (Covovax) and India’s own mRNA vaccine.

Reading list

• For the best guides to the latest research, check out The Atlantic (summary of all the studies), Nature (more nerdy), New York Times and New York magazine.
• And for more on the variant, read our previous explainer.
• The Hindu explains the two sub-lineages of Omicron.
• Stat News has more on the SA study on vaccine escape—while Economic Times reports on why Indian experts are sceptical. 
• The Wire has details of the UK study on Covishield.
• National Geographic assesses the effectiveness of booster shots—while Indian Express has the latest scoop on the government’s thinking on the matter.
• Scroll reports on the S-gene failure test—and potential problems of supply.