COVID cases are on the rise in many countries as dangerous new sub-variants evolve faster and faster. At the same time, individual tests are being carried out below.
That might seem like a dangerous combination. If authorities cannot precisely control where and how fast the virus is spreading, they may not be able to help protect vulnerable communities.
Fortunately, there is a way to track SARS-CoV-2 without relying on drive-thru testing sites or testing at pharmacies, clinics, or hospitals. Increasingly, scientists are looking for the virus in sewage water. In our toilet tanks, in other words. “Sewage appears to be the key to early detection, especially in the context of increased at-home testing and potentially reduced reporting,” Niema Moshiri, a geneticist at the University of California, San Francisco, told The Daily Beast. Diego.
But there is a big problem with this sewage surveillance. Any method of monitoring a global pandemic itself must be global. While North America, Europe, Australia, and parts of Asia have fairly good sewage monitoring systems, China, the country that is arguably the most vulnerable to COVID right now,not.
With China’s own individual testing dependent on Beijing’s unsustainable COVID-zero lockdown policy, the country should start switching to sewage surveillance, experts explained in a new scientific study. It will not be easy.
It is important not to exaggerate the recent slight increase in global COVID cases. A handful of highly contagious new coronavirus sub-variants, the children of the Omicron variant that first appeared last fall, are driving surges in cases in the United States, South Africa and some other countries, including North Korea.
Thanks to vaccinations and lingering antibodies from past infections, these waves are not as bad or as deadly as previous waves. Amid an overall global decline in COVID, the US has seen a spike in infections, from an annual low of 30,000 daily new cases in late March and early April to 85,000 daily new cases last week. Meanwhile, South Africa saw daily new cases rise from 1,300 to 7,700 over the same period.
Of course, hospitalizations and deaths aren’t increasing that much, again thanks to all those vaccines and antibodies. What is perhaps more concerning is the decline in testing that has been followed along with the rise in infections. At the same time that COVID is on the rise, it seems that we are losing our original tool for tracking the disease.
In the US, we were testing 2.5 million people every day at pharmacies, drive-thru sites, and other places who reported their test results to state authorities, who in turn reported them to the Centers for US Disease Control and Prevention Today we are testing only 55,000 people a day. Individual tests are also collapsing in other countries.
“To meet future challenges in public health emergencies, it is vital to monitor wastewater.”
There is a very good reason for this drop. Home tests are now cheap, reliable, and readily available. The administration of US President Joe Biden even offers eight free antigen tests per household.
When you test at home, there is no obligation to report your results to authorities. Millions of people around the world may get COVID, get tested, self-isolate, and recover, all without their government knowing.
Possible, but not likely. In the US, for example, the CDC moved quickly in 2020 to establish a national wastewater monitoring system that now includes 886 sites spread across all 50 states, tribal lands, and US territories.
The testers draw water from water treatment plants, sewers, and septic tanks, test for SARS-CoV-2, and record the results. Random sample sequencing can determine exactly which variants and subvariants are present in a particular community. It was sewage monitoring that warned us of a regional increase in Omicron subvariant BA.2.12 in and around New York beginning in late March.
European countries, Australia and countries in Asia have also increased their own sewage monitoring. A global surveillance system is taking shape, one that does not rely on voluntary individual testing.
It’s not perfect, of course. “The wastewater data is intended to be used with other COVID-19 surveillance data,” the CDC emphasized on its website.
Wastewater surveillance “doesn’t provide the same degree of localization as reported clinical trials,” Rob Knight, head of a genetics computation lab at the University of California, San Diego, told The Daily Beast. “The Point Loma wastewater treatment plant in San Diego covers 2.3 million people, so he doesn’t know if the signal is coming from specific areas like he would with clinical trials.”
However, home tests that go unreported don’t provide any public health information, so sewage is better than that.”
The biggest problem is China. Not only do China’s 1.4 billion people represent 18 percent of the world’s population, but China is more vulnerable to COVID than most countries. The Chinese government’s zero COVID policy, which locked down city after city to prevent the spread of the virus, had a tragic side effect.
For more than two years, almost no one in China contracted COVID, which means that almost no one in China had natural antibodies when the extremely contagious Omicron variant and its sub-variants appeared, breaking through city lockdowns in Hong Kong, Shenzhen, and other cities. . It didn’t help that the Chinese government has promoted locally made vaccines that may not be as effective as the best Western-made mRNA injections.
New daily cases in China peaked at 30,600 in late April. Since then, they have been reduced to less than 10,000. But much of China remains in lockdown. And as long as that’s the case, individual testing isn’t really a problem. Health authorities in major cities can require and enforce frequent testing at government-run sites.
But experts agree: China’s zero-COVID strategy is unsustainable. In addition to being highly unpopular with many Chinese, it is also slowing China’s economic growth and risking a recession in China and in countries that depend on trade with China.
If and when zero-COVID ends, individual testing in China could collapse in the same way it has collapsed in other countries. And there is no nationwide wastewater monitoring system to pick up the slack in the data. Still. “To meet future challenges in public health emergencies, it is vital to monitor wastewater,” explained a team led by Ying Zhang, an environmental engineer at China’s Fuzhou University, in a new academic study.
Part of the problem is that, for all its rapid economic growth over the last generation, China is still a developing country, and its development is uneven. That is evident in the sewage system. “The pipeline allocation across the country is unbalanced,” Ying’s team wrote. Drainage is concentrated in the industrial east at the expense of the rural west, leaving potential gaps in surveillance.
And the pipes that do exist are not always well built. “Because the operation, management and maintenance of the drainage system have not attracted much attention in China, serious problems occur within the drainage system, such as leakage, overflow and clogging, in many cities.” Blocked and leaky pipes can damage samples.
In light of the challenges, Ying and his co-authors proposed to start small with a partial surveillance system in the largest cities and expand from there, as infrastructure allows. In any case, China must do something to anticipate a possible fall in the individual tests.
The pandemic is not over. New variants and subvariants are arriving. If we’re not going to get tested at the corner pharmacy, then we need someone to check our pipes. And this has to happen all over the world.