New Delhi plans mass screening effort as virus cases surge

NEW DELHI (AP) — Indian authorities are launching a massive coronavirus survey taking down health details from New Delhi's entire population of 29 million, and testing everyone with symptoms by July 6.

The new plan was announced Wednesday after the sprawling capital became the worst-hit city by the pandemic in India with 70,390 cases, exceeding the financial capital of Mumbai.

In the past 24 hours, 3,788 new cases were confirmed in Delhi, compared to 1,118 in Mumbai. India on Thursday registered another record high of 16,922 cases, taking the total to 473,105.

So far, the strategy in Delhi — the territory that encompasses the capital city — had revolved around identifying containment zones, or areas with large clusters of cases. But officials said that less than a fifth of all cases came from the zones, and broader surveillance was needed.

Nearly half of the cases in Delhi were part of viral clusters, and the search for them through “vigorous contact tracing of COVID positive patients will be undertaken to analyze the reasons for clustering,” the city government said.

Officials said teams will go to each household to identify and test anyone with symptoms using an antigen test, a cheaper and more efficient though less accurate blood test that looks for antibodies — proteins made by the body days or weeks after fighting an infection.

The test diagnoses active infections by detecting the earliest toxic traces of the virus. While acknowledging that antigen tests aren't as accurate as the gold standard RT-PCR tests, officials said that “highly suspicious cases” who test negative on the antigen test will be administered an RT-PCR test to rule out a false result.

Meanwhile, the new plan also envisions a redrawing of the city's 266 containment zones. On June...