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The promise of antigen tests emerged like a miracle this summer. With repeated use, the theory went, these rapid and cheap coronavirus tests would identify highly infectious people while giving healthy Americans a green light to return to offices, schools and restaurants. The idea of on-the-spot tests with near-instant results was an appealing alternative to the slow, lab-based testing that couldn’t meet public demand. (Song, 11/16)

A rapid finger-prick test designed to show whether a person has previously been infected with SARS-CoV-2 is significantly less accurate than earlier research suggested, scientists report in a new study. The AbC-19 Rapid Test, developed for use by healthcare professionals in the UK and EU, looks for antibodies against the virus in a small drop of blood from a finger-prick, and can show results in just 20 minutes, without needing specialised lab equipment. (Dockrill, 11/16)

Data published today in Morbidity and Mortality Weekly Report (MMWR) shows that resource-intensive, symptom-based airline passenger entry screening identified few laboratory-diagnosed COVID-19 cases—only 1 case for every 85,000 travelers screened. The researchers also highlight the inadequacy of electronic airline data for contact tracing, finding that only 22% of records contain both the traveler's phone number and physical address. (11/13)

Tyson Foods Inc. is using infection-tracking algorithms and ongoing employee testing to shield workers at the biggest U.S. meatpacker from a fresh surge in coronavirus cases and keep grocery stores stocked, its chief executive said. The Arkansas-based company, like other meatpackers, is spending heavily on protective gear and planning longer-term defenses against Covid-19. Tyson Chief Executive Dean Banks said the company is adding more space for workers at existing plants and designing new ones to include workstation dividers and other safeguards. (Bunge, 11/15)

It’s true that getting a positive result tells you some crucial information: It’s time to cancel all your plans and isolate until you’re past the point of infectiousness. A negative test, though, doesn’t guarantee that anyone is Covid-free, and it’s never license to let down your guard. You might, for instance, contract the virus in the interim between being tested and receiving your results, or between getting your results and seeing your friends and family. (The testing site itself could even be where that happens.) Even if you assume these tests are 100 percent accurate, they’ll only tell you what your status is at the specific time the test is done. (Aschwanden, 11/15)

For many Americans these days, the mere idea of leaving the house prompts a question: “What’s the risk?” And often, they find that even after scrutinizing data on novel coronavirus cases and poring over public health recommendations, there still isn’t a clear answer. (Chiu, 11/13)