Coronavirus antibody tests may not end the pandemic
A FORMER government health adviser has warned that COVID-19 antibody tests may not be the solution t..
By admin, in Health , at April 28, 2020
A FORMER government health adviser has warned that COVID-19 antibody tests may not be the solution to ending the coronavirus pandemic.
Mass public testing is seen as a vital precondition for lifting the month-long lockdown, that has ground the UK economy to a halt. Many people have had COVID-19 without realising, because either they had no symptoms or because they had only a very mild form of the disease. To help establish whether someone was infected, tests have now been developed that supposedly are able to detect antibodies in the blood.
These are produced by the immune system to fight off viruses and infections. Professor Karl Sikora, a cancer specialist, ordered immunity tests from South Korea that were checked in German laboratories. The test were then given a further examination by a high quality private laboratory. Out of 108 people tested, only eight positive samples were detected.
The chief medical officer of the Rutherford Cancer Centres said: “We know the virus has been in our buildings, so the prevalence simply has to be higher. “It seems many people exposed to the virus don’t develop the antibodies measured by these tests. “Young people, in particular, must be seeing off the virus by some other mechanism before it triggers any antibody response.” According to a recent study by scientist at Fudan University in China, up to 30 percent of COVID-19 patients do not develop enough antibodies to protect them from reinfection.
Researchers carried out tests on 175 people, who had recovered from the potentially fatal disease. Results showed that older and middle-aged patients had much higher levels of antibodies than younger ones. Tests were unable to detect antibodies in ten of these patients due to the very low levels of antibodies. Professor Sikora thinks that the low level of positive antibody tests he s seen suggests that T-cells and natural killer cells may be responsible for getting rid of the infection, particularly in younger people.
Despite the unreliability of the antibody tests, some scientists still believe it is worthwhile to carry out the testing. Dr Nick Beeching, a consultant in infectious diseases at Liverpool School of Tropical Medicine, told the Daily Mail: “Most people should produce a positive antibody test 14 to 28 days after infection. “These tests can stay positive for many years, or immunity can go down quite quickly.”
Coronaviruses, which were first identified in the 1960s, are a main cause of minor colds. However, the immune system rapidly ‘forgets’ what they look like and the same virus can cause re-infection within as little as four months. “It is around 18 months for SARS and MERS, but in the case of Covid-19 we don’t know how long immunity may last,” says Dr Beeching.
He added: “Also, there’s a need for better tests.” Earlier this month, the government spent £16 million on 3.5 million fingerprick antibody tests imported from China, and placed further provisional orders for 17.5 million tests from nine firms, including ones based in the UK. But after testing all of them, Public Health England decided none was accurate enough to use, with some only showing a 50-60 percent accuracy rate.