The British government has admitted that none of the 17.5m antibody tests it ordered in the fight against the coronavirus pandemic worked well enough to be used.
The ministers strongly hoped that the arrival of the tests would give a much clearer picture of the number of people infected with Covid-19, paving the way for possible relaxation of the locking restrictions.
The failure of the tests is a major setback and suggests that Britain may be further away from being able to launch an effective mass testing program.
The government is working with nine companies that have developed anti-coronavirus antibody tests, which test whether someone has recovered from the disease and is likely to be immunized. The tests are being evaluated by researchers at the University of Oxford – but each has so far been shown to be unreliable.
“Unfortunately, the tests we have reviewed to date have not worked,” wrote Professor John Bell, Regius professor of medicine at the University of Oxford, on Monday.
“We see a lot of false negatives (tests where no antibody is detected despite the fact that we know it is there) and we also see false positives. None of the tests we validated would meet the criteria for a good test, as agreed with the Medicines and Health Products Regulatory Agency. It is not a good result for the test providers or for us, ”he said.
Last week, Secretary of Health Matt Hancock said the government had placed an interim order for 17.5 million antibody tests. “We will only use them if they work,” he said.
Downing Street confirmed on Monday that “no test has so far been good enough to use” and said it is working with companies to improve their quality.
“No government in the world has deployed a comprehensive antibody test program,” added a spokesman for the Prime Minister.
The government has issued orientation on his test plans this weekend, saying that if the antibody tests “don’t work, no more tests will be purchased and, if possible, orders will be canceled.”
Ministers hoped to send home antibody test kits, although medical community has said it would not be appropriate.
Many Covid-19 antibody tests on the market claim high accuracy rates. However, since they were developed in just a few months, many claims are based on only a few hundred samples.
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To be considered accurate, the devices must be able to distinguish the presence in the blood of a person of antibodies specific to this coronavirus, and also to identify antibodies in people who have had relatively mild strains of the disease. .
“One of the problems with this kind of work is that you can jump too fast. When you don’t have enough samples, you can be misled: 100 tests may sound good, but after 20,000 they may not be, “said Paul Hunter, University professor of medicine from East Anglia.
Professor Bell said that Oxford researchers will continue to look for a test that works. “The government will work with new and old suppliers to try to achieve this result so that we can step up antibody testing for the British public. It will take at least a month, ”he said.