Crucial antibody tests in US raise alarms

WASHINGTON • The US has seen in recent weeks the first roll-out of blood tests for coronavirus antibodies, widely heralded as crucial tools to assess the reach of the pandemic in the country, restart the economy and reintegrate society.

But for all their promise, the tests - meant to signal whether people may have built immunity to the virus - are raising alarms.

Officials fear the effort may prove as problematic as the earlier launch of diagnostic tests that failed to monitor which Americans - and how many - had been infected with or developed Covid-19.

The federal government has now been faulted by public health officials and scientists for green-lighting the antibody tests too quickly and without adequate scrutiny.

The Food and Drug Administration (FDA) has allowed about 90 companies, many based in China, to sell tests that have not received government vetting, saying the pandemic warrants an urgent response.

But the agency has since warned that some of these businesses are making false claims about their products; health officials have found others to be deeply flawed.

Tests of "frankly dubious quality" have flooded the US market, said Mr Scott Becker, executive director of the Association of Public Health Laboratories.

Many of them, akin to home pregnancy tests, are easy to take and promise rapid results.

Most tests now available mistakenly flag at least some people as having antibodies when they do not, which could foster a dangerously false belief that those people have immunity.

And the federal guidance is so confusing that healthcare providers are administering certain tests unaware that they may not be authorised to do so. Some are also misusing antibody test results to diagnose the disease, not realising that they can miss the early stages of infection.

"People don't understand how dangerous this test is," said Dr Michael Osterholm, an infectious disease expert at the University of Minnesota.

"We sacrificed quality for speed, but in the end, when it's people's lives that are hanging in the balance, safety has to take precedence over speed."

As government agencies, firms and academic researchers scramble to validate existing tests and create better ones, there are doubts whether they can deliver as promised. And even if the tests do improve, their availability could be hampered by the same manufacturing shortages that have prevented the Covid-19 diagnostic tests from scaling up adequately.

Widespread screening is considered critical as President Donald Trump presses to reopen the country and several states are considering lifting lockdowns.

Last Friday, Mr Trump cheered the FDA's emergency approval of some antibody tests, saying they would support efforts to get Americans back to work "by showing us who might have developed the wonderful, beautiful immunity".

NYTIMES