Antibody test restrictions lifted

(CNS): Cayman has undertaken 1,461 antibody blood tests, largely among healthcare workers and those who have had COVID-19 or were close contacts of those that have. But on Friday Chief Medical Officer Dr John Lee said he would be lifting the restrictions on this type of testing because he didn’t think it was revealing much information that public health can use at the moment to manage the virus.

From the testing that has taken place, just 49 people had antibodies and only seven samples came from those who had not tested positive for the virus previously or had been known to be in contact with someone who had.

Dr Lee said that PCR and molecular testing would remain the preserve of public health. But the restrictions on healthcare providers being able to officially do antibody testing would be loosened, though public health officials would still like to collect the information, he said.

“I don’t really feel that antibody testing is revealing that much information,” the CMO said. “We still wish to collect the information but the information it is providing, we are not sure exactly how to use at the moment.” However, he noted that in time, “our knowledge and understanding of how to interpret the tests” would improve.

He said antibody testing was currently being done as a result of scientific interest but it was not driving any policy decisions.

While the testing is a way of confirming the rate of infection, the numbers here are very low, and there is a lack of scientific knowledge about how long COVID-19 antibodies last and their effectiveness in preventing people from being infected. The tests do not yet offer any quick fixes regarding management of the pandemic or surety about immunity.

While some governments are now banking on a vaccine and herd immunity as a way of halting the spread of the virus, there are numerous studies now that indicate the immunity people with the antibodies have acquired could be short lived, which means a single-shot vaccine may not be enough.

Research by scientists at King’s College London showed the antibodies peaked about three weeks after symptoms showed up, and then vanished rapidly. Another Chinese study had shown similar results. In addition, recently published data indicated that 60% of patients tested while they had COVID-19 were seen to have produced the antibodies that were dubbed ‘potent’. But at the end of the three-month testing period, only 17% recorded the same level of potency.

A new accurate rapid finger-prick test that can tell within 20 minutes if a person has been exposed to the virus, developed by Oxford University, has now been approved in the UK and will be on sale in the coming weeks. The government is making plans to distribute tests to healthcare professionals first before making them available for people to use at home.