This month, India has recorded the world’s sharpest spike in coronavirus infections, with political and financial capitals New Delhi and Mumbai running out of hospital beds, oxygen, and medicines.
Scientists are studying what led to an unexpected surge, and mainly whether a variant of the novel coronavirus first detected in India is to blame.
The variant, named B.1.617, has been reported in some 17 countries, rising global concern.
Here are the basics:
What is the Indian variant?
The B.1.617 variant contains two critical mutations to the outer “spike” portion of the virus that attaches to human cells, said senior Indian virologist Shahid Jameel. The World Health Organization said the predominant lineage of B.1.617 was first identified in India last December, although an earlier version was spotted in October 2020.
WATCH: India’s infections of coronavirus cross 18 million
The WHO has described it as a “variant of interest”, suggesting it may have mutations that 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 categorized as “variants of concern,” a higher threat level.
Are variants driving the surge in cases?
It’s hard to say.
The WHO says more study is urgently needed. Laboratory-based studies of limited sample size suggest potential increased transmissibility, it concluded.
The picture is complicated because the highly transmissible B.117 variant first detected in the UK 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, Dr. Singh said.
Prominent US disease modeler Chris Murray from the University of Washington said the sheer magnitude of infections in India in a short period suggests an “escape variant” may be overpowering any prior immunity from natural infections in those populations.