At the high level, there are two reasons for the steep drop in Coronavirus in India:
1. Localized herd immunity in the cities. Link above points to results from Mumbai. Recent studies from Delhi have also shown similar numbers (>50% of population with antibodies).
2. Low testing in rural areas. It's hypothesized that a lot of the current spreading of the virus is happening silently in rural area, where testing infrastructure is underdeveloped.
The WHO's January 20th memo on PCR threshold which advised labs to verify cycles are at a level which doesn't generate a high false positive rate?
“[a]fter thorough investigation, WHO confirmed that the tests were not always being used appropriately and in accordance with the instructions provided by the manufacturer.”
“In particular, users in laboratories encountered problems with these tests when they did not apply the recommended positivity threshold — this can result in either false negative results (if the threshold applied is lower) or false positives (if threshold is higher),” the WHO said.
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[ 2.8 ms ] story [ 15.7 ms ] threadAt the high level, there are two reasons for the steep drop in Coronavirus in India:
1. Localized herd immunity in the cities. Link above points to results from Mumbai. Recent studies from Delhi have also shown similar numbers (>50% of population with antibodies).
2. Low testing in rural areas. It's hypothesized that a lot of the current spreading of the virus is happening silently in rural area, where testing infrastructure is underdeveloped.
“[a]fter thorough investigation, WHO confirmed that the tests were not always being used appropriately and in accordance with the instructions provided by the manufacturer.”
“In particular, users in laboratories encountered problems with these tests when they did not apply the recommended positivity threshold — this can result in either false negative results (if the threshold applied is lower) or false positives (if threshold is higher),” the WHO said.