Smriti Mallapaty in Nature:
The pandemic is sweeping through India at a pace that has staggered scientists. Daily case numbers have exploded since early March: the government reported 273,810 new infections nationally on 18 April. High numbers in India have also helped drive global cases to a daily high of 854,855 in the past week, almost breaking a record set in January. Just months earlier, antibody data had suggested that many people in cities such as Delhi and Chennai had already been infected, leading some researchers to conclude that the worst of the pandemic was over in the country.
Researchers in India are now trying to pinpoint what is behind the unprecedented surge, which could be due to an unfortunate confluence of factors, including the emergence of particularly infectious variants, a rise in unrestricted social interactions, and low vaccine coverage. Untangling the causes could be helpful to governments trying to suppress or prevent similar surges around the world. European countries such as France and Germany are also currently experiencing large outbreaks relative to their size, and nations including Brazil and the United States are reporting high infection rates at around 70,000 a day. But India’s daily totals are now some of the highest ever recorded for any country, and are not far off a peak of 300,000 cases seen in the United States on 2 January.