1. What’s different about this variant?
The omicron variant is characterized by some 30 or more changesin the spike protein, half of which are in the area that binds to the enzyme that the virus targets to enter cells and cause an infection. Mutations there can make the pathogen less recognizable to the antibodies made in response to vaccination or a case of Covid, increasing the risk of either a breakthrough infection or reinfection. At least three mutations are associated with helping the virus escape detection from antibodies and another appears to increase its ability to gain entry to human cells, making it more transmissible.
Explainer:
2. Where did it come from?
Scientists have focused on Africa as a potential source, but it’s not yet certain exactly where or how the variant originated. It was first identified from testing done Nov. 9 in Botswana on travelers from West Africa, according to authorities in Nigeria. It was reported to the World Health Organization on Nov. 24 after cases were identified among young, unvaccinated people in South Africa. Researchers in the Netherlands detected the variant in patient specimens collected Nov. 19 to 23, but it wasn’t immediately clear whether those people had visited southern Africa. A scientist at the UCL Genetics Institute in London said omicron likely evolved during a chronic infection of an immuno-compromised person, possibly in an untreated HIV/AIDS patient. The beta variant, a mutation identified last year in South Africa, also may have come from an HIV-infected person.
Read more:
3. How infectious is it?
U.K. data show an increased probability that someone with an omicron infection will spread it, with faster growth rates than what is seen with delta, the variant that became the dominant strain worldwide in mid-2021. Omicron infects up to
4. How virulent is it?
The jury is still out. The WHO said in its Dec. 21 report that the data on that point remained limited. Preliminary results from two studies in the U.K. suggested a
5. Do vaccines work against it?
Lab experiments indicate omicron can evade immunity from natural infection and vaccines more than other variants, and results in a substantial reduction in the production of neutralizing antibodies in the blood -- a key indicator of protection against illness. Still, the findings suggest protection conferred by existing Covid vaccines won’t be totally wiped out.
6. What treatments will work?
Steroids and medications known as IL6 receptor blockers, which can suppress a harmful overreaction of the immune system, will still be effective for managing patients with severe Covid, according to the WHO. Other treatments are being
The Reference Shelf
- The WHO’s weekly briefings on the pandemic.
- Physician-scientist
Eric Topol explains why omicron is ominous. - Salim S. Abdool Karim and Quarraisha Abdool Karim describe omicron’s emergence as a new chapter in the Covid pandemic in a commentary piece in The Lancet.
- Bloomberg Intelligence’s
Sam Fazeli explains the effectiveness of vaccineboosters against omicron. - Bloomberg Intelligence says we should worry about the
new variant . CDC information on variants.
(Updates with new studies in section 4)
--With assistance from
To contact the reporters on this story:
To contact the editors responsible for this story:
Lisa Beyer, Paul Geitner
© 2021 Bloomberg L.P. All rights reserved. Used with permission.
To read more articles log in.
Learn more about a Bloomberg Law subscription.