Coronavirus antibody tests could be the key to reopening the global economy, but they're still a long way from being a magic bullet.
The race to reopen the global economy is on. Policymakers around the world are looking for ways to restart business activity and avoid further damage without reigniting coronavirus outbreaks.
With the prospect of a vaccine looking unlikely for at least 18 months, efforts to return life to some form of normalcy hinge on one goal. Widespread antibody testing, which would allow people to know whether they’ve already been exposed to coronavirus.
If they have been, they’re likely immune and could return to work. The plan sounds bulletproof on paper, which might explain why it’s generated so much optimism. But in practice, sending thousands of supposedly immune people back to work is a lot harder than it sounds.
Assuming an accurate antibody test is created, it would take time to deliver and administer those tests to the public. In the U.K., the potential use of antibody tests has been postponed until at least May. Even if that goal is reached, it will be some time before the tests are widely available.
And the government would have to work out a system by which to identify those who’ve been tested in order to allow them back into the public. It’s unclear how at-home tests would be administered in a way that would confirm a person indeed has antibodies.
But even more important than timing is the issue of accuracy, which has proven to be a major stumbling block.
As it stands, there are no usable antibody tests available in any country. That’s because working out whether or not people are immune to a virus that isn’t fully understood is a tricky business.
Researchers at the University of Oxford say a usable test is at least weeks away. The impact of false results could be dire. It would send potentially unprotected individuals back out into the workforce. That could spark a second wave of coronavirus outbreaks leading to a higher death toll and unnecessary economic damage.
The FDA granted emergency authorization for an antibody test developed by Cellex, but other countries have yet to stand behind those tests— which claim to be 93% accurate. According to Professor John Newton, chief of Covid-19 testing in the U.K., finding a test sensitive enough to detect all levels of coronavirus infections has proven challenging.
We want to use the test in the context of a wider range of levels of infection including people who are quite mildly infected.
Those who experience only mild cases of coronavirus tend to develop fewer antibodies initially which could create a false negative.
But false positives are a more concerning scenario. That’s something Dr. Newton says has created a delay in evaluating the antibody tests on the market. His research uses blood donated before the Covid-19 outbreak to determine whether similar antibodies will create a false positive.
There are a number of other coronaviruses circulating that might stimulate antibodies that cross react to Covid-19 proteins.
Yet even when a usable antibody test is approved for widespread use, that may not be enough to protect against a second wave of infections.
According to the Korean Center for Disease Control and Prevention, there’s some evidence that coronavirus can “reactivate” in previously infected individuals.
More than 50 patients who were supposedly “cured” in South Korea went on to test positive for coronavirus. The CDC says it believes the people weren’t reinfected, but that the virus reactivated.
While we are putting more weight on reactivation as the possible cause, we are conducting a comprehensive study on this. There have been many cases when a patient during treatment will test negative one day and positive another.
Similar cases were reported in China when people reportedly recovered from the virus and then went on to test positive. Some believe faulty testing is behind double infections, while others say the intensity of the coronavirus infection may not have produced the necessary antibodies to keep from getting reinfected.
If reinfection or reactivation is possible, that could erase the argument for widespread antibody testing.
Disclaimer: The opinions expressed in this article do not necessarily reflect the views of CCN.com.
Last modified: September 25, 2020 8:41 PM