Unraveling the mysterious mutations that make delta the most transmissible Covid virus yet

Upon first inspection, the mutations in the highly contagious delta covid variant don’t look that worrisome.

For starters, delta has fewer genetic changes than earlier versions of the coronavirus.

“When people saw that the epidemic in India was driven by delta, they did not suspect it would be so bad or overtake other variants,” said Trevor Bedford, an evolutionary biologist at the Fred Hutchinson Cancer Research Center.