[Early on in the pandemic, COVID] infections climbed dramatically for months and at one point India looked like it might overtake the United States as the country with the highest case toll.
But infections began to plummet in September, and now the country is reporting about 11,000 new cases a day, compared to a peak of nearly 100,000, leaving experts perplexed.
They have suggested many possible explanations for the sudden drop — seen in almost every region — including that some areas of the country may have reached herd immunity or that Indians may have some preexisting protection from the virus.
The Indian government has also partly attributed the dip in cases to mask-wearing, which is mandatory in public in India and violations draw hefty fines in some cities. But experts have noted the situation is more complicated since the decline is uniform even though mask compliance is flagging in some areas.
It’s more than just an intriguing puzzle; determining what’s behind the drop in infections could help authorities control the virus in the country, which has reported nearly 11 million cases and over 155,000 deaths. Some 2.4 million people have died worldwide.
“If we don’t know the reason, you could unknowingly be doing things that could lead to a flare-up,” said Dr. Shahid Jameel, who studies viruses at India’s Ashoka University.