Getting An Antibody Test For The Coronavirus? Here's What It Won't Tell You
May 21, 202010:28 AM ET
Salvador Perez got really sick in April. He's 53 and spent weeks isolated in his room in his family's Chicago apartment, suffering through burning fevers, shivering chills, intense chest pain and other symptoms of COVID-19.
"This has been one of the worst experiences of his life," says Perez's daughter, Sheila, who translated from Spanish to English for an interview with NPR. "He didn't think he was going to make it."
Perez recovered and now wants to go back to work as a chef at a Chinese restaurant. But his boss told him he needs a test — an antibody test — first. So he found a place to get one and tested positive. His blood indeed has antibodies to the novel coronavirus — proteins that his immune system produced when it fought off the pathogen.
"He feels great that he can get ... back to work, since we haven't really paid our bills," Sheila Perez says. "And he feels great that he can start doing what he did before the virus again."
But her father is also nervous. His doctor told him the antibodies might give him some protection against catching the virus again but also stressed that's far from guaranteed.
"He's anxious that he doesn't want to get sick. He's kind of scared of going back to work because ... he might go through it again," his daughter says.
Salvador Perez is right to be worried. It's still not certain that antibodies measured by such a test would protect him from catching the virus again. And if the antibodies are protective, it's unknown how strong that protection might be or how long it might last. There are also questions about the reliability of many antibody tests being sold.
Researchers are urgently trying to answer those uncertainties and figure how best to conduct antibody testing.
Nevertheless, increasing numbers of people are getting the tests — many without recognizing how much is still unknown about what the results mean.
Some employers, such as Perez's restaurant, are requiring workers to take antibody tests if they want to continue working or return to their jobs. Others are getting employees tested to see how widely the virus has spread through their workforce and to try to find ways to improve worker safety. And some labor unions are helping workers get tested in hopes of offering them some sense of security against the virus.
In addition, some individuals are buying the tests themselves out of curiosity and to use as a basis for personal decisions, such as whether it's safe to start spending more time with close friends and extended family members who are outside the household.
But the idea of using antibody testing in these ways worries many doctors and public health authorities because there are many common misconceptions.
For starters, the antibody tests are only a sign of past infection. Whether the infection is actually gone can only be determined by a diagnostic test that identifies genetic material from the virus or viral particles.
Some people also falsely think testing positive on an antibody test proves they can't get infected with the virus again.
"I think people just want this to go away and want to resume their normal lives," says Kelly Wroblewski, director of infectious disease for the Association of Public Health Laboratories. "But my fear is [antibody tests are] going to be used as this sort of golden ticket to demonstrate immunity — when we just don't know if that's the case."
Still, Wroblewski and others acknowledge the results might offer at least some useful guidance in certain cases.
"If I had a household where I had a number of younger individuals in the household, one of whom had antibodies, I think that that individual would probably be the safest bet to be able to safely go to get the groceries," says Michael Mina, an assistant professor of immunology and infectious disease at the Harvard T.H. Chan School of Public Health.
But, Mina quickly adds, "I still wouldn't want that individual going to get groceries and then going the next day to a nursing home to see Grandma." Having antibodies against the coronavirus is just no guarantee that you won't pick up or pass along an infection, he says.
https://www.npr.org/sections/health-shots/2020/05/21/857961304/getting-an-antibody-test-for-the-coronavirus-heres-what-it-wont-tell-you