India's massive COVID surge puzzles scientists

Re:India's massive COVID surge puzzles scientists by nyokodo on Thursday April 22, 2021 @03:37AM (#26899887)

> The person is tested and the PCR-test shows a positive result for covid-19. Which is true from a month earlier.

PCR tests detect viral DNA in a specimen. To have viral DNA in a specimen requires an active infection as DNA from dead viral particles doesn’t sit around for a month in the patient’s respiratory system. As the immune system responds and eliminates the infection repeated PCR tests will eventually show a negative result. Perhaps you’re thinking of antibody tests?

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Re:India's massive COVID surge puzzles scientists by 3dee on Thursday April 22, 2021 @05:11AM (#26900522)

As far as I know it does not detect DNA but RNA. RNA degrades slowly and it is estimated it can take 1 to 3 months to be completely gone.

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Re:India's massive COVID surge puzzles scientists by nyokodo on Thursday April 22, 2021 @07:09PM (#26909234)

You are correct since they use RT-PCR specifically for SARS-CoV-2. However, the number of cycles used in the process is key, <= 24 cycles produces very few false positives for active infection. The OPs explanation for the increased rate doesn’t match this fact.

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