Coronavirus: Rush to develop rapid tests

If you are only coughing, that's not enough. If you want to be tested for SARS-CoV-2, as a rule, you not only have to have symptoms, but you also have to have been in contact with someone who was infected. These are the guidelines of the Robert Koch Institute, Germany's central authority for the identification, surveillance and prevention of infectious diseases.

But didn't the head of the World Health Organization, Tedros Adhanom Ghebreyesus, say, "Test, test, test?" And wouldn't it make sense to test as many people as possible  and only then to decide who should be quarantined instead of locking down an entire country? Why the current restrictions?

Christian Drosten, who is head of the Institute of Virology at Berlin's Charite University Hospital and has been advising the German government on coronavirus, recently explained in a regular podcast produced by the German public broadcaster NDR that there were too many people who really have reasons to be tested.

"This has completely used up all the capacity we have," he said.

Limited testing capacity

Currently, there are only estimates as to how many tests are being carried out, and these sometimes contradict themselves. A survey conducted by the Robert Koch Institute of 174 laboratories found that 483,295 tests had been carried out before March 22, mostly in the previous two weeks.

The German Ministry of Health told DW that it was "currently assuming a capacity of at least 300,000 tests a week, a capacity that is being increased continuously."

Read more: Up to 30% of coronavirus cases asymptomatic

Drosten even speaks of estimates suggesting that 500,000 tests are currently being conducted in Germany every week. Roland Stahl from the National Association of Statutory Health Insurance Physicians (KBV) told DW that last week (March 16-22), 266,000 tests had been conducted on outpatients alone, either by GPs consultants, with some 80 labs sending results to the KBV every week. The KBV says the capacity is limited to 360,000 tests per week.

Public health insurance providers pay about €60 ($66) per test if the criteria of the Robert Koch Institute are fulfilled, said Stahl. But media reports say labs will charge up to €250 per test to those with private health insurance schemes or paying out of their own pocket.

It is one of the peculiarities of Germany's health care system that the KBV is only collecting data on tests carried out by registered doctors. It has no information on how many tests are being carried out by hospitals or other local health authorities. However, it must be just over 200,000 if the entire figure is half a million. This would also correspond to the data of the German Ministry of Health.

How fast is fast enough?

This means Germany is testing on a relatively large scale and thus can well bear comparison to South Korea, which was able to stem the rate of infection by conducting a huge number of tests, all without imposing national lockdowns.

Read more: US approves 45-minute coronavirus test

In Germany so far, most of the tests being conducted are PCR tests, which detect the virus itself and are considered to be particularly accurate. The test takes about five hours in the laboratory, but patients still have to wait a couple of days for results, as the samples have first to be sent to the lab by the doctor. In addition, the tests cannot be analyzed fully automatically, meaning that they cannot be processed round the clock, as the lab staff is lacking.

But it would, of course, be good to test more and to test faster, which is what scientists are working towards, both state and private providers. Hardly a day goes by without a company introducing a new, simpler or faster test.  

My test, my machine

On Thursday, Bosch Healthcare Solutions announced that it had developed a rapid test that could deliver results in 2.5 hours. It is a fully automated PCR test that just involves putting a swab into a cartridge, which a machine then analyzes.

The snag is that this machine has to be a Bosch device from its Vivalytic series. Bosch Healthcare Solutions spokesman Thomas Berroth explained to DW that because the device was brand-new and had only been given the green light in February, there are currently only a "few dozen" operating in the country.

From the company's point of view, the fact that this analysis device can deliver such rapid results for coronavirus is a good selling point. DW could not find out how much they cost. They are due to come out on the market next month, targeted at hospitals and labs, not registered doctors.

Other companies are also designing rapid PCR tests that work with similar cartridges and special, mostly in-house analytical devices. The US firm Cepheid has developed a rapid test that takes 45 minutes, according to its own data, and the Dutch pharmaceuticals holding Qiagen has come up with a test that takes one hour.

Large-scale rapid testing

Apart from the PCR tests, there are also rapid tests that detect viral antigens, which trigger the body to produce antibodies. These tests are simple and very fast, delivering results in 15 minutes or less. Though not as accurate as PCR tests, experts say that their sensitivity is relatively high.

South Korea has been using these tests a lot as they can be carried out on a large scale in a short amount of time. Drosten predicts that they will probably be introduced in Germany as well and might eventually take over from PCR tests if they are available in larger numbers.

But whether test results take one or five hours, the main problem remains: If there is no analytical device on hand when a swab is taken, samples still have to be sent elsewhere for analysis, and this simply takes time.

PCRs, antigens and antibodies

Rapid tests that detect antibodies are even faster and simpler, but they are a very different category. They do not detect the virus itself as PCR tests do but analyze the body's reaction to infection. A person who is infected will develop antibodies after about 10 days.

The disadvantage of these tests is that they are of no use in the early infection phase. The advantage, says Drosten, is that they can answer the question of how many people were infected "without noticing that they had the disease or without taking it seriously because they just had a bit of a sore throat. But if these people test positive for antibodies, we can assume that they are now immune."

So they don't need to be quarantined unnecessarily and also contribute to herd immunity. They are the "60 to 70% of the population that will have to have been infected with the virus before the pandemic can come to a halt," according to Drosten. 

The next big thing

He also says that it is important to have access to reliable data on this score so as to better predict how the virus might unfold. "These will be the next big pillar of information," says Drosten, aside from the daily announcements of infections and deaths. "But these antibody tests have only just been developed and there are only a few companies that can supply them in large quantities."

Accuracy is also a problem. The tests have to detect antibodies for SARS-CoV-2 without simply identifying antibodies for other harmless coronaviruses. "At the moment, these tests are still in the development and licensing phase and not yet available," said the Robert Koch Institute. Drosten has predicted that these tests will be introduced across the board within two to three months. 

Making money with tests 

What is certain is that there is money to be earned with these tests. Anybody who offers for sale a self-testing kit that is as easy to use as pregnancy tests could make a fortune at the moment. There are already many test kits being sold online, many of them produced by Chinese companies. Christian Drosten warned in the NDR podcast that they should be seen "with caution," as not enough studies had been conducted to validate them.

This week, the South Korean firm Celltrion announced that it was developing an antibody-based self-testing diagnostics kit that would deliver results in 20 minutes. But it will not come out on the market until this summer.

Money can also be made with regular tests that take longer, however. The South Korean company SolGent received a license for a test kit in February that delivers results in two hours, which it is now selling all over the world.

Early this week, the company announced that it would sell 30,000 test kits to the Munich-based Synlab Group. According to the Korea Times, a million tests have been ordered by various US states, too.

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