US top infectious disease expert Anthony Fauci has warned of the risks of a new Covid-19 variant, first identified in India, which is now spreading widely in the UK.
The Delta variant, known by the scientific name B.1.617.2, has spread from where it was first discovered in India to over 60 countries, according to the World Health Organization, Xinhua reported.
More than 6 percent of the sequenced Covid-19 infections in the US trace to the highly transmissible Delta variant, Fauci said on Tuesday.
The variant has become the dominant strain in the UK, accounting for an estimated 60 per cent of new cases, replacing the B.1.1.7 strain, according to Fauci.
He called on more Americans to get vaccinated to keep the new variant from proliferating across the country.
When was it Identified?
The World Health Organization (WHO) said the predominant lineage of B.1.617 was first identified in India last December, although an earlier version was spotted in October 2020.
The WHO has described it as a "variant of interest", suggesting it may have mutations that would make the virus more transmissible, cause more severe disease or evade vaccine immunity. Other strains with known risks, such as those first detected in the United Kingdom, Brazil and South Africa, have been categorised as "variants of concern," a higher threat level.
The WHO says more study is urgently needed. Laboratory-based studies of limited sample size suggest potential increased transmissibility, it concluded.
Why is it Complicated?
The picture is complicated because the highly transmissible B.117 variant first detected in the U.K. is behind spikes in some parts of India. In New Delhi, UK variant cases almost doubled during the second half of March, according to Sujeet Kumar Singh, director of the National Centre for Disease Control. The Indian variant, though, is widely present in Maharashtra, the country's hardest-hit state, Singh said.
Prominent U.S. disease modeller Chris Murray, from the University of Washington, said the sheer magnitude of infections in India in a short period of time suggests an "escape variant" may be overpowering any prior immunity from natural infections in those populations.