Coronavirus: What are new antibody tests bought by government and when will they be available?

The UK government has purchased 3.5 million coronavirus antibody tests, raising hopes the kits could soon be rolled out to NHS staff and the public.

Professor Sharon Peacock, director of Public Health England’s National Infection Service, told MPs on Wednesday the tests were being checked for accuracy in laboratories this week and could be ready to use within a matter of days. She said they would be distributed to the public through Amazon and pharmacies.

But the UK’s chief medical officer, Professor Chris Whitty, later dismissed suggestions the kits could be available to buy online as soon as next week. He stressed frontline NHS workers would be prioritised for tests once they are available.

So what are the tests bought by the government and when can we expect them to be rolled out in the UK?

What are antibody tests?

The tests are designed to detect Covid-19 antibodies in a person’s blood. Antibodies are proteins made by the immune system to fight invaders such as bacteria and viruses. Their presence in the blood indicates that the body has fought off the disease and is therefore very likely to be immune from reinfection.

The testing kit looks similar to a pregnancy test and involves pricking a finger to produce a drop of blood, which is then analysed for two types of antibodies - with results available in just 15 minutes.

Will it tell you if you have coronavirus?

No. The antibody test can confirm whether someone has previously had Covid-19, but does not detect whether someone currently has the disease and remains a risk to others.

This means the kits will not address a key pressing concern of many hospitals, where a lack of coronavirus tests means NHS staff have been forced to isolate at home with undiagnosed symptoms and are unable to work.

The government has vowed to increase real-time tests for coronavirus to 25,000 a day, but on Wednesday only 6,491 were carried out - up from 5,605 on Monday.

So why would they be useful?

If they work, the tests would allow doctors and nurses who have had symptoms to know whether they had Covid-19, enabling them to return to work sooner and treat patients without fear of infecting them. Members of the public who learn they have had the virus would be able to stop social distancing and return to a relatively normal life.

Widespread testing could also allow Public Health England to build up a better picture of the spread of the disease, including by identifying people who were infected but showed no symptoms.

Can we be sure they’re accurate?

Not yet. Health chiefs are mindful that a test that does not work would be worse than no test at all, and the antibody kits are currently being checked at a laboratory in Oxford to ensure they are accurate before roll-out.

Sir Patrick Vallance, the government’s chief scientific adviser, has said accuracy is key, even if it meant the tests are available later than planned.

He told Wednesday’s Downing Street press conference: “If you tell somebody they’re immune from it, and they’re not, that is not a good position to be in. We must make sure that we get the quality of this absolutely right.¨

Will the public be able to buy them?

Prof Peacock suggested the tests would eventually be available to the public through Amazon and high street pharmacies, telling the Science and Technology Committee: “"In the near future people will be able to order a test that they can test themselves, or go to Boots, or somewhere similar to have their finger prick test done."

But Prof Whitty downplayed the prospect of that in the near future, stressing that making the tests available to frontline NHS workers was the priority.

He said: “I do not think - I want to be clear - that this is something we will suddenly be ordering on the internet next week.

"We need to go through the evaluation, then the first critical uses, and then stretch it out from that point of view."

He added there was a "global bottle neck" on the supply of the tests as other countries also look to obtain them, meaning shortages were likely.