A new variant of Covid-19 discovered in South Africa called B.1.1.529 has caused a flight ban and a scramble to determine the effectiveness of the vaccine.
It is the latest strain of coronavirus to emerge since the start of the pandemic, including the delta variant that is now dominant, first detected in India in October 2020.
Globally, delta has surpassed other virus strains in most countries and accounted for 99.8% of consecutive cases in the last 60 days according to the latest weekly report from the World Health Organization. (WHO).
This was followed by the gamma variant, which accounted for 0.1% of the sequenced cases, followed by alpha and beta, each accounting for just under 0.1%.
Lesser known variants such as mu and lambda are rarely sequenced.
However, WHO says that at the regional and national levels, there are differences in which strains of the virus prevail, especially in some South American countries where the delta spreads more slowly.
The emergence of variants is a natural process that occurs when the virus mutates to ensure its survival over time.
Most mutations have little or no effect on the virus’ ability to infect or cause severe illness.
But certain mutations can affect how easily viruses spread, how severe the disease they cause, and how well vaccines respond to them.
WHO experts tracking the evolution of Covid-19 gathered on Friday to determine whether it should be classified as “concern” or “concern”.
They say it will take “several weeks” to understand how widespread B.1.1.529 is and the severity of the illness it can cause.
Currently, WHO only classifies alpha, beta, gamma and delta variants as “of concern”.
They are considered worrisome because they are very contagious or make the disease worse.
Mu and lambda are considered “variants of interest” because they show genetic changes that mean they have the potential to become more contagious, harder to detect, or cause more severe disease.
All variants are classified by “lineage” and have a specific place in the family tree that originated with the first SARS-CoV-2 virus.
The delta variant is twice as infectious as previous variants, and the vaccine is about 40% less effective at preventing infection from delta than the other variants.
(Except for the title, this story has not been edited by NDTV staff and is published from an aggregated feed.)