Testing drop complicates Covid fight
Testing for Covid-19 has plummeted around the world, making it much tougher for scientists to track the course of the pandemic and spot new, worrisome viral mutants as they emerge and spread.
Experts say testing has dropped by 70 to 90% worldwide from the first to the second quarter of this year – the opposite of what they say should be happening with new omicron variants on the rise in places such as the United States and South Africa.
‘‘We’re not testing anywhere near where we might need to,’’ said Dr Krishna Udayakumar, who directs the Duke Global Health Innovation Center at Duke University in North Carolina. ‘‘We need the ability to ramp up testing as we’re seeing the emergence of new waves or surges to track what’s happening’’ and respond.
Reported daily cases in the US, for example, are averaging 73,633, up more than 40% over the past two weeks, according to data compiled by Johns Hopkins University. But this is a vast undercount because of the testing downturn and because tests are being taken at home and not reported to health departments.
An influential modelling group at the University of Washington in Seattle estimates that only 13% of cases are being reported to health authorities in the US – which would mean more than a half million new infections every day.
The drop in testing was global, but the overall rates were especially inadequate in the developing world, Udayakumar said.
The number of tests per 1000 people in high-income countries is around 96 times higher than it is in low-income countries, according to Geneva-based public health non-profit FIND.
What’s driving the drop? Experts point to Covid fatigue, a lull in cases after the first Omicron wave, and a sense among some residents of lowincome countries that there’s no reason to test because they lack access to antiviral medications.
Testing, genomic sequencing and delving into case spikes can lead to the discovery of new variants. New York state health officials found the super-contagious BA.2.12.1 variant after investigating higher-than-average case rates in the central part of the state.
Testing increases as infections rise and people develop symptoms – and it falls along with lulls in new cases. But experts are concerned about the size of the drop after the first Omicron surge, the low overall levels of testing globally, and the inability to track cases reliably.
Another way to keep better track of the pandemic, experts said, was to bolster other types of surveillance, such as wastewater monitoring and collecting hospitalisation data. But those have
their own drawbacks, as hospitalisation trends lag behind cases.
Udayakumar said scientists across the world must use all the
tracking methods at their disposal to keep up with the virus, and would need to do so for months or even years to come.
At the same time, he said, steps had to be taken to boost Covid testing in lower-income countries.