Different governments around the world have responded to the coronavirus pandemic in very different ways, and one aspect that varies significantly is testing for Covid-19.
So what tests are available and how widely is testing done in different countries?
What tests for the corona virus are there?
Some tests – such as those currently being used in British hospitals – are used to see if someone currently has Covid-19.
They are done by taking a swab from the nose or throat and sending it to a laboratory where they look for signs of the genetic material of the virus.
Another type of test – an antibody test – is needed to determine if someone has had the virus.
This type works by looking for signs of immunity by dripping blood onto a device, like a pregnancy test.
The British government has bought three and a half million antibody tests, but has yet to find one reliable enough to come into widespread use.
How reliable are the tests?
Diagnostic tests used in hospitals are very reliable.
However, this does not mean that it will detect every case of coronavirus. A patient at the very beginning of the infection or with a relatively small amount of virus may test negative.
And the smear could turn out to be negative if it didn’t pick up enough virus from the throat.
So far, antibody tests have not proven to be so reliable.
British Health Secretary Matt Hancock said last week that 15 of the most promising antibody tests had been tested, but none were good enough.
Professor John Newton, who is leading the UK’s testing, told The Times that tests brought from China were able to identify antibodies in patients who were seriously ill with coronavirus, but did not detect it in milder cases.
Why is testing important?
There are two main reasons for testing people – to give them an individual diagnosis and to determine how far the virus has spread.
This second information could help health services plan for additional demand, including intensive care units.
Testing can influence decisions about social distancing measures. For example, if it is discovered that a large number of people are already infected, then the decision to impose lockdowns may become less necessary.
And without widespread testing, it could turn out that many people are self-isolating unnecessarily, including healthcare workers.
How comprehensive are countries testing?
South Korea, which was able to test much more comprehensively than the UK, reacted very quickly with approval to manufacture testing kits, allowing large stocks to be built up.
Despite having a slightly smaller population than the UK, it has twice as many laboratories and around two and a half times the weekly testing capacity.
Germany has carried out more than three times as much testing as the UK.
By March 27, it had tested 1,096 people per 100,000 citizens, while by April 1 Great Britain had tested 348 per 100,000 residents.
For comparison, Italy tested 895 per 100,000 population, South Korea 842 per 100,000, the US 348 per 100,000 and Japan 27 per 100,000 population.
