Immunity tests: how do they work and when will they be ready?

Millions of tests that can detect whether a person has ever been infected with coronavirus will be available “within weeks”, according to The Times.

Robert Jenrick, the housing and communities secretary, said: “It will be a very simple one to use and it will be similar to taking a pregnancy test.”

Jenrick’s comments came as the government announced a £20m investment to study and better understand the spread of Covid-19.

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Last week, the Prime Minister said that a “game-changing” test that can identify people who have been infected and consequently now have immunity was close to being developed.

How does the test work?

According to The Sun, the new test “goes further than the current method which only diagnoses those who are currently infected with the disease”.

The existing test “detects the virus’ genetic material in oral or nasal swabs”, says Wired. This means that it is highly effective, but “only returns a positive result when the virus is still present in the body”.

The magazine adds that the new test uses “serological testing”, meaning it will tell doctors if a person crossed paths with the coronavirus weeks or even months ago – sometimes without knowing.

This, Wired reports, will mean we can start to collect figures “modelling the spread of Covid-19”, so the government can “make accurate public health decisions”.

Lack of testing is said to be hampering efforts to free up beds for coronavirus patients, with some hospitals reporting that care homes are refusing to accept discharged patients unless they have been tested for the virus, according to Health Service Journal.

Commenting on the new test, Boris Johnson said: “The great thing about having a test to see whether you’ve had it, is suddenly a green light goes on above your head and you can go back to work safe and confident in the knowledge that you are most unlikely to get it again.”

When will the new tests arrive?

Wired reports that dozens of prospective serological test kits for Covid-19 have been developed all around the globe since the start of February.

Details on the latest test, the magazine says, from Icahn School of Medicine in New York City, were published just two days ago.

In Singapore and South Korea, serological tests have already been used on a large scale in national surveillance programmes that are likely to give scientists the first population data on just how widespread Covid-19 has been within a particular nation.

Speaking at the daily Downing Street press conference last Thursday, Patrick Vallance, the government’s chief scientific adviser, said Public Health England’s work on the antibody test is “progressing very fast”, said ITV.

Following the Prime Minister’s promise last week to ramp up testing in hospitals to 25,000 a day, Jenrick told the BBC that the government had ordered “millions” of the serological testing kits, adding that they will be available “in the coming weeks”.