Omicron facts are emerging; here’s what scientists say now
The COVID variant spreads fast, and can be detected by RT-PCR; and there’s no evidence to prove the infection is ‘milder’ than Delta
This time two weeks ago, Omicron (pronounced oh·mai·krawn) was just a lesser-known Greek alphabet. Today, it’s the single biggest source of fear to people worldwide who have survived two deadly waves of COVID, and are worried that the latest variant may be more lethal than its predecessors.
Scientists are in a race against time to understand the latest SARS-CoV-2 strain better, so that they can come up with remedies and prevention measures. Pharmaceutical companies are adapting their vaccines to combat the mutant variety of coronavirus even as governments are looking at ways to contain the spread.
The key concerns are on whether the Omicron spreads faster than the other variants, whether it cause greater harm, and whether it is vaccine-resistant. While information on the strain is changing by the hour, there appears to be some clarity vis-à-vis what was available two days ago. Here’s the latest:
Where was the Omicron till now?
With available data, researchers have discerned that the Omicron — whose scientific name is B.1.1.529 — is a direct descendant of the original COVID strain, B.1. It has not descended from any of the other COVID variants of concern (VOC), such as Alpha, Beta or Delta.
A Wire Science article notes that the latest strain’s closest evolutionary connection was identified in April 2020, when the pandemic was still in its early stages. In the 18 months since, various forms of the strain have been circulating, undetected, in countries where genomic surveillance is relatively low. Alternatively, it could have evolved in an immune-suppressed patient and then entered the general pool.
Either way, it did not appear overnight — in Africa alone it is suspected to have gone unidentified for at least two months, in which time it changed its form up to 50 times. This places the time of emergence of the latest strain at September-October 2021. But, it was identified — thanks to meticulous genomic surveillance carried out by South African researchers — only in the third week of November. This could probably mean the variant doesn’t spread too rapidly, though that is in direct contrast to what the WHO suspects.
How far will vaccines go?
Viruses mutate in a bid to land the configuration that suits them best, and the coronavirus is no different. It has thousands of variants that are mostly harmless — or at least only as harmful as the original strain. For instance, the Beta and Delta variants proved more infectious than the rest.
The Omicron alone comes with around 50 mutations. Over 30 of them are centred on the germ’s spike protein, which helps it attach itself to human cells. It is the spike protein that current vaccines attack. Hence, scientists say it is possible that the current vaccines may be ineffective on Omicron. This makes the variant vastly different from the rest. Pharma majors such as Pfizer are pivoting their resources to adapt their vaccines to fight Omicron, and it will be at least a few weeks before the first results emerge.
Also, the WHO, going by existing data, has inferred that Omicron is spreading seven times as fast as the Delta, which itself was considered highly virulent. Since the variant has as yet been identified only in select geographic pockets, the data available is incomplete and insufficient.
Will travel bans help?
When the first wave of COVID struck, many governments including India’s faced criticism for not closing their borders in quick time. Now, though, experts say a travel ban is futile at best and counterproductive at worst.
Omicron cases have been reported in 13 countries, some of which are far away from southern Africa, such as Hong Kong, Israel, Germany, England, Austria and Australia. The number of cases is mounting by the hour. Hence, a travel ban doesn’t address any part of the problem at this point of time.
What could possibly be more effective is to scale up testing at airports for all international passengers, irrespective of their origin or destination points. Implementing mandatory quarantines may also help, but be difficult to implement, considering most nations have opened up air travel.
How effective is an RT-PCR?
Scientists have expressed doubts on RT-PCR tests being able to distinguish between the Omicron and other variants, but the WHO says they can. A complete RT-PCR report for COVID includes a test for N, S, E and ORF genes. Omicron comes under the S category. The absence of the S gene and the presence of other genes is an indirect way of knowing that Omicron is present in the sample.
The WHO said in a statement, “The widely used PCR tests continue to detect infection, including infection with Omicron, as we have seen with other variants as well. Studies are ongoing to determine whether there is any impact on other types of tests, including rapid antigen detection tests. However, some PCR can also detect this deletion (of S) without the need for full-genome sequencing.
“In fact, this is one bit of good news that we do have: we can easily track the spread of the Omicron variant – perhaps easier than we could track the Delta – because of the SGTF, which creates a specific pattern in PCR test results.”
Does the variant enjoy an edge?
In select South Africa provinces, the Omicron is currently the dominant variant of COVID, replacing the Delta, which could reflect its transmission advantage. The Omicron is estimated to have a growth advantage of 0.38-0.43 per day as against the Delta. This means its transmissibility is 280% more than that of the Delta.
The transmission advantage may also give the Omicron better immune evasion properties. i.e, better ability to overpower the body’s immune system. Further, it may present a greater reinfection threat, attacking those who have already recovered from COVID and developed sufficient antibodies. But these are very early days yet and the data is highly insufficient, say experts.
How severe is the infection?
There is speculation that the Omicron may be, though highly infectious, ‘milder’ than the Delta — that its hospitalisation and fatality rates are low.
However, hospitalisation is said to be rising in Omicron-hit provinces in South Africa. Taking into account the time lag between infection onset and severe disease, only the next few weeks are likely to reveal how mild or not the Omicron is. The variant has been detected in several youngsters, which is again cause for concern.
Medical experts caution against thinking the Omicron may be mild, for it may lead to laxity in COVID-appropriate behaviour. Whatever may be the strain, basic precautions such as washing hands frequently, masking up and avoiding crowds would stand a vaccinated person in good stead, they say.