Coronavirus: India hunts for new strains as Covid wave looms

Like all viruses, the coronavirus that has caused the deadly pandemic keeps changing in small ways as it passes from one person to another.

The vast majority of these mutations are inconsequential, and don’t alter the way the virus behaves.

But some mutations trigger changes in the spike protein that the virus uses to latch on to and enter human cells – these variants could potentially be more infectious, cause more severe disease or evade vaccines. Such variants have been already identified in UK, South Africa and Brazil, and have now spread to dozens of countries.

Last week, a top US health official warned that the spread of highly contagious variants was threatening to fuel a “potential fourth surge of cases” in the country. The Brazil variant appears more contagious and may evade immunity provided by past infection, scientists say. The British variant is responsible for a chunk of new infections in US and Europe.

Genome detectives around the world are hunting down these worrying mutations. Scientists are able to detect changes by sequencing the genome of the virus after taking a swab from an infected patient. They crack the genetic code of the virus – essentially prising open its instruction manual – and begin tracking the mutations.

India was the fifth country in the world to sequence the genome of the novel coronavirus, isolated from its first recorded cases in the southern state of Kerala in January last year. Since then the country has recorded more than 11 million cases – just behind the US – and more than 150,000 deaths from the disease.