It's all based on antibody testing—and the science just isn't there yet.

By Leah Groth
May 01, 2020
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On March 16, the White House launched its "Slow the Spread" campaign—initially, a 15-day run (that was eventually extended another 30 days), to reduce the spread of COVID-19 across the US. Those guidelines quietly expired on Thursday, April 30 (President Trump explained that the guidelines "[will] be fading out because now the governors are doing it," during a recent meeting with Louisiana Governor John Bel Edwards).

With the onus on the governors, states will slowly start opening back up—depending on how affected they've been by the pandemic—and some people are hopeful that "immunity passports" may provide previously-infected people with a fast-pass to getting back to work and other aspects of daily life.

But not everyone is thrilled with these "risk-free certificates" to give those who've already had COVID-19 an expedited way back into society. The World Health Organization recently issued a statement recommending against immunity passports, due unclear science on whether infection by COVID-19 offers full protection from a subsequent infection. "There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection," the WHO explained in its statement. "At this point in the pandemic, there is not enough evidence about the effectiveness of antibody-mediated immunity to guarantee the accuracy of an 'immunity passport' or 'risk-free certificate.'"

What exactly is an immunity passport?

The idea of immunity passports is based on antibody testing, according to Georgine Nanos, MD, MPH, physician & CEO Kind Health Group—and that in itself is a very "complicated situation" right now with COVID-19.

Dr. Nanos explains that in a perfect world, an antibody test would be able to determine if someone had previously been infected by or exposed to COVID-19 through the presence of antibodies, or proteins produced by the body to fight infection, in the blood. Joseph Vinetz, MD, a Yale Medicine infectious disease specialist and professor at Yale School of Medicine, points out that antibody testing can be incredibly important in identifying patients who had the virus and didn’t know it, perhaps due to the fact that they were asymptomatic. 

"The hope is that the presence of an IgG antibody to COVID-19 may concur some level of immunity to patients who may have already been exposed," says Dr. Nanos. In that case—and again, in the best possible scenario—those who test positive for antibodies and theoretically incur protection from both acquiring COVID-19 and passing it to others, may then be able to go out into the workforce sooner to jumpstart the economy. 

Why are experts cautious about immunity passports?

Currently, there is no flawless antibody testing method. “The first problem is that we don't have widely available and reliable rapid antibody testing for COVID-19 in the United States yet,” says Dr. Nanos. She adds that even the most reliable antibody tests that are currently on the market require individuals to go into a lab facility like Quest or LabCorp and have their blood drawn with a turnaround time of 1 to 3 days. But “what is needed most right now is a quick turnaround rapid antibody test with results in 15 minutes," she says.

Dr. Nanos says the antibody testing situation in the US became even more complicated when the FDA began allowing for emergency authorization for smaller lab companies to bring some of these tests to market—primarily in an effort to increase testing overall. Unfortunately, that move allowed many tests on the market "with zero scientific oversight, and as result we have a lot of unreliable tests now flooding the market and no way of knowing which ones are valid.”

Ultimately, it's this lack of accurate and timely testing that points to another issue with immunity passports: "We don't have enough data yet to now if there is any immunity from having COVID-19 IgG antibodies," says Dr. Nanos. And even if people do acquire immunity to COVID-19 after being infected with the virus, there's no telling yet how long that immunity may last. Dr. Vinetz agrees not enough evidence is available yet to support the validity of immunity passports. "Antibody testing results do not have any proven relationship to protective immunity," he says.

It's important to remember, however, that none of this means prior exposure to or infection of COVID-19 will absolutely not provide protection—it just has yet to be completely proven. After some confusion surrounding its response to immunity passports, the WHO amended that, while there's insufficient evidence of COVID-19 protection after exposure, "we expect that most people who are infected with #COVID19 will develop an antibody response that will provide some level of protection," according to a tweet by the agency.

But overall, Dr. Nanos maintains that antibody testing as a means to provide those with immunity passports is premature and "may give people a false sense of security." She does add, however, that antibody testing is still an important part of the fight against COVID-19, in “helping us understand how much of the disease has already spread throughout our community and [guiding] decision-making on reopening businesses.”

Instead of going all in on immunity passports for those who have been tested for and confirmed to have antibodies to the new coronavirus, the Infectious Diseases Society for American recommends "people with antibodies not change their behavior in any way," which includes continuing social distancing, Mary Hayden, MD, spokesperson for IDSA and chief of the Division of Infectious Diseases at Rush University Medical Center recently told CNN, adding that the issues with antibody testing right now could put people at unnecessary risk. 

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDCWHO, and their local public health department as resources.

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