“There are anecdotal reports of reinfections and of cases in vaccinated individuals, but at this stage it’s too early to tell anything.”
- Penny Moore, virologist, University of Witwatersrand, Johannesburg
“All these things are what give us some concern that this variant might have not just enhanced transmissibility, but might also be able to get around parts of the immune system.”
- Richard Lessells, infectious diseases specialist, KwaZulu-Natal Research and Innovation Sequencing Platform
Memories of a marvelous Thanksgiving get together with family and friends were still fresh in my mind, when on November 26, the World Health Organization (WHO), declared SARS-CoV-2 B.1.1.629 as the newest Variant of Concern (VOC) that qualified for the Greek letter designation, Omicron. I’m sure everyone’s reaction to this news was similar to mine, “As if we needed yet another viral variant to worry about!”
What are VOCs? The WHO and the Center for Disease Control and Prevention (CDC) closely monitor a number of genetic variants of SARS-CoV-2 that are circulating around the world. Many are considered Variants of Interest (VOI), but to reach the level of apprehension of a VOC, one or more of these features must be demonstrated: greater transmissibility, greater disease severity, increased evasion of the immune system, including of neutralizing antibodies elicited by vaccination.
By joint decree of the WHO and CDC, VOCs are identified by letters of the Greek alphabet. You may recall reading about Alpha (first seen in the UK in December, 2020), Beta (identified in South Africa in December, 2020), Gamma (a variant that emerged in Brazil in November, 2020), Delta (a particularly notorious variant first seen in India in October 2020 that because of marked increased transmissibility has been sweeping the world ever since), and now the fifth VOC Omicron.
What is known about Omicron so far? Two features of the Omicron variant have disturbed the experts the most and led to the rapid VOC designation. First, virologists have identified more than 30 mutations in the Omicron’s SARS-CoV-2 spike protein. You may recall that the virus uses this protein to gain entry to cells bearing ACE2 receptors. It is also a major target for most, if not all, current vaccines that protect against COVID-19.
The second worry is the rapidity of Omicron’s spread in southern Africa. First spotted in four vaccinated people in Botswana in early November, it triggered a sharp increase in cases in South Africa, especially around the economic hub of Johannesburg. Omicron also has been detected in travelers to Hong Kong from South Africa who had received the Pfizer/BioN Tech vaccine.
Who’s getting infected? Most of the cases of SARS-CoV-2 Omicron infection have been among young people. And, not surprisingly, most cases have occurred in the unvaccinated (only about 25% of those between 18-34 years of age in South Africa are vaccinated).
Stay calm and get vaccinated. While more is being learned about the biology of the SARS-CoV-2 Omicron variant, including its transmissibility, virulence, and its ability to evade our most effective weapon (the current vaccines), many countries have banned travelers arriving from southern African countries. Similarly, it’s probably not the best time to be traveling to this area of the world.
In the meantime, vaccination remains crucial, including in countries, like those in southern Africa, with limited resources. As Dr. Tedros Adhanom Ghebreyesus, Director-General of WHO, has stated, “A global pandemic requires no less than a world effort to end it. None of us will be safe until everyone is safe. Global access to coronavirus vaccines, tests and treatments for everyone who needs them, anywhere, is the only way out.”