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Links for 2020-07-05

  • Rapid, inexpensive home testing for COVID-19 may get us out of this mess before a vaccine

    We should welcome [rapid covid] tests, even if less accurate, and broadly adopt them for widespread community use. Here’s why: They will be cheap. Estimates are that they would cost between 1 and 5 dollars. That’s around the price of a cup of coffee. They can be done on saliva. No brain biopsy required. They can be done frequently. Every day for college students, or healthcare workers, or bus drivers? Every third day for everyone? They will answer the key question — am I contagious to others right now? Finally, and most importantly, they will answer this last question quickly. Results back in less than an hour. Anyone with a positive test can self-isolate, be reported to public health officials, participate in a contact tracing program, and be monitored for symptoms. Maybe pre-emptive antiviral therapy will prevent severe illness. We can choose to do a rapid home test any day we go to work, or to the gym, or to meet friends in a restaurant, or to attend a concert, or to pray in a house of worship, or to visit an elder loved one, or indeed partake in any activity we do in groups that now sadly may sustain the pandemic. And for those worried about lack of sensitivity, two items of reassurance. First, false negatives are less likely when people have the highest amounts of virus in saliva and respiratory secretions — and this is when they’re most contagious to others. If the test is falsely negative due to low titers of virus, it may not matter very much. Second, this modeling study finds that the frequency of testing is the key determinant of how well a broad testing strategy will limit the spread of the virus. It’s even more important than test sensitivity, and evidence that imperfect testing is better than no testing at all.

    (tags: testing covid-19 pcr rt-pcr false-positives false-negatives viruses)

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