Countries straining to contain a second wave of COVID-19 are turning to faster, cheaper but less accurate tests to avoid the delays and shortages that have plagued efforts to diagnose and trace those infected quickly.
Germany, where infections jumped by 4,122 on Tuesday to 329,453 total, has secured 9 million so-called antigen tests per month that can deliver a result in minutes and cost about 5 euros ($5.90) each. That would, in theory, cover more than 10% of the population.
The United States and Canada are also buying millions of tests, as is Italy, whose recent tender for 5 million tests attracted offers from 35 companies, reported Reuters.
Germany’s Robert Koch Institute (RKI) now recommends antigen tests to complement existing molecular PCR tests, which have become the standard for assessing active infections but which have also suffered shortages as the pandemic overwhelmed laboratories and outstripped manufacturers’ production capacity.
PCR tests detect genetic material in the virus while antigen tests detect proteins on the virus’s surface, though both are meant to pick up active infections. Another type of test, for antibodies the body produces in response to an infection, can help tell if somebody has had COVID-19 in the past.
Like PCR (polymerase chain reaction) tests, antigen tests require an uncomfortable nasal swab. They can also produce more “false negatives”, prompting some experts to recommend they only be used in a pinch.
Still, the alarming rise in new infections globally has health officials desperately pursuing more options as the winter influenza season looms.