Testing for COVID-19 has declined sharply around the world, making it much harder for scientists to track the course of a pandemic and detect new, alarming viral mutants when they appear and spread.
Experts say testing fell 70-90% worldwide from the first to the second quarter of this year – the opposite of what they say should happen to new variants of omicron growing in places like the United States and South Africa .
“We do not conduct testing where it may be needed,” said Dr. Krishna Udayakumar, who runs Duke Global’s Innovation Center at Duke University. “We need the opportunity to step up testing as we watch new waves or jumps appear to keep track of what’s going on” and respond.
For example, daily cases in the U.S. average 73,633, up 40 percent over the past two weeks, according to data collected by Johns Hopkins University. But this is a significant understatement due to the decline in testing and the fact that the tests take place at home and are not reported to the health department. An influential group of models from the University of Washington in Seattle estimated that the U.S. health service reports only 13% of cases, which would mean more than half a million new infections each day.
The drop in testing is global, but overall figures are particularly inadequate in the developing world, Udayakumar said. According to the Geneva-based non-profit health organization FIND, the number of tests per 1,000 people in high-income countries is about 96 times higher than in low-income countries.
What drives the fall? Experts point to fatigue from COVID, a lull in cases after the first wave of omicrons and the feeling in some low-income residents that there is no reason to test because they do not have access to antiviral drugs.
At a recent World Health Organization press briefing, FIND Director-General Dr Bill Rodriguez called the testing “the first victim of a global decision not to be wary” and said “we are becoming blind to what is happening with the virus”.
Testing, genome sequencing, and deepening in disease cases may lead to the discovery of new variants. New York State health officials found a super-contagious version of BA.2.12.1 after an investigation in the central state of higher-than-average cases.
Looking ahead, “we just won’t see how the new options are the way the previous options are,” Rodriquez told The Associated Press.
Testing increases as infection increases and symptoms appear in humans – and falls along with a lull in new cases. Testing is rising again in the US along with a recent surge.
But experts are concerned about the size of the fall after the first micron surge, the low overall level of testing worldwide and the inability to reliably track cases. Although tests at home are convenient, only tests sent to the lab can be used to identify options. If fewer tests are performed and fewer of these tests are processed in laboratories, fewer positive samples are available for sequencing.
In addition, home testing results are largely invisible to tracking systems.
Mara Aspinal, managing director of a consulting firm from Arizona that tracks testing trends on COVID-19, said that home testing is at least four times greater than PCR, and “we get virtually zero data from home-based testing.”
This is because there is no single mechanism for people to report outcomes to local health departments that are not staffed. The CDC urges people to inform their physicians, who in most places should report diagnoses of COVID-19 to health authorities.
However, as a rule, the results of home tests fall under the radar.
Reva Sevilla, a 36-year-old mother from Los Angeles, was tested at home this week after experiencing symptoms such as a sore throat, cough and congestion. After the results were positive, she took two more tests to make sure. But her symptoms were mild, so she did not plan to go to the doctor and tell anyone about her results.
Beth Barton of Washington, Missouri, who works in construction, said she passed about 10 home tests before visiting her parents or if she developed symptoms that she thought could be COVID-19. All returned negative. She shared the results with others, but did not know how to report them.
“It takes a whole system to do that,” said Barton, 42. “We as a society do not know how to determine where we are.”
Aspinal said one potential solution would be to use technologies such as QR code scanning to report the confidentiality of home test results.
Another way to better monitor a pandemic, experts say, is to step up other types of surveillance, such as sewage monitoring and hospitalization data collection. But they have their drawbacks. Sewage monitoring remains diverse, not covering all areas, and hospitalization trends are lagging behind.
Udayakumar said scientists around the world should use all the tracking techniques available to them to keep up with the virus, and do so for months or even years.
At the same time, he said, steps need to be taken to step up testing in low-income countries. He said demand for tests would increase if access to antiviral drugs improved in those places. And one of the best ways to increase the amount of testing is to integrate it into existing health services, said Wadzanai Muchenje, who manages health and strategic partnership in Africa for the Rockefeller Foundation.
George Benjamin, executive director of the American Public Health Association, said the time would come when the world would stop extensive testing for COVID-19 – but that day has not yet come.
“As the pandemic continues and the virus is still unpredictable, it is unpleasant for us to worry only about human health,” he said. “We have to worry about the population.”