Omicron, a highly transmissible variant of the coronavirus that causes Covid-19, has spread around the world in a matter of weeks since it was first identified in southern Africa.
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.
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.
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.
Yet public health experts say those reports need to be interpreted with caution because many occurred in young people with no significant risk factors, and many had been vaccinated or previously infected.
The Imperial College London team estimated that having two doses of the Pfizer-BioNTech vaccine or the one from AstraZeneca Plc reduces the odds of getting a symptomatic omicron infection by about 20% — about the same as having previously had Covid.
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.