Who’s immune to COVID-19? Checking for virus antibodies

Bill Colacurcio’s currently home in Maywood recovering from what he believes was a mild case of COVID-19. But he never actually got tested for the disease, so last week the business analyst got his blood drawn to check for COVID-19 antibodies — showing his body’s immune response to the virus. He tested positive.

“By getting a positive test, I feel better about going out in public. Again, I’m using a mask, using protective gloves, and all that type of stuff, but I feel better about actually going out there and engaging with people,” he said.

Antibody testing’s becoming widely available now. At Bergen New Bridge you need a doctor’s referral. The CEO says the test answers a fundamental question for many folks.

“For people who may have had a mild infection, didn’t know they had the coronavirus, to know that they have developed antibodies to it,” said Deborah Visconi, president and CEO of Bergen New Bridge Medical Center.

It definitely isn’t for people sick with COVID-19 symptoms — they get the nasal swab or saliva test. Instead, antibody tests focus on those who’ve had the disease, or wonder if they’ve ever been exposed to the virus. In the most accurate tests, blood is drawn, spun in a centrifuge and tested for presence of two different antibodies.

Results give government officials a much bigger sample than people who tested positive for the actual disease — more than 121,000 in New Jersey. Think of that group as just the tip of the iceberg.

“So if we measure antibodies, we can have the size of the entire iceberg — both the part above the water and the part below the water. And this is very important for many things,” Rutgers New Jersey Medical School’s Dr. Maria Laura Gennaro said.

For the CDC and New Jersey officials trying to reopen the state, antibody tests help show where the virus spread and which part of the population it affected, along with who’s still vulnerable.

According to Hudson Regional’s Dr. Nizar Kifaieh, immunity might fade.

“For people who have tested positive a while back and are asymptomatic right now, have they developed immunity? Yes or no? And that’s really important because it’s going to teach us a lot about what’s going to happen next. Everybody’s talking about the second wave that may happen in wintertime, so if these people develop immunity, the next question is how long will that immunity last?” Kifaieh said.

Doctor’s simply don’t know, which is why a positive antibody test doesn’t give complete clearance, experts warn.

“The serology tests are not meant to be an immunity passport. We don’t know if its useful information for whether a person can return to work safely without the possible risk of reinfection, for example,” said state epidemiologist Dr. Tina Tan.

Doctors believe, antibodies also help fight the disease. At Holy Name and Mount Sinai, they’re testing recovered COVID-19 patients and looking for people with a high level of antibodies who could donate convalescent plasma to treat current patients battling the virus.

“We’re seeing that they’re having lower fever. We’re seeing that their oxygenation is better. And my clinician’s gut response is that they think plasma is going to be a proven treatment for coronavirus,” said Dr. Adam Jarrett, chief medical officer at Holy Name Medical Center.

Many patients have been clapped out of hospitals after getting plasma treatments loaded with antibodies. Absent a reliable vaccine, it’s a path to recovery and possible immunity.