Can You Contract COVID-19 Twice? What Experts Say About Coronavirus Antibodies

Coronavirus COVID-19

With more than 900,000 coronavirus cases and counting, the U.S. has surpassed all other affected countries with the most confirmed COVID-19 (coronavirus) cases in the world. It’s not a superlative to be proud of, and concern over the pandemic is still mounting as some governors begin reopening business. Even with the green light from their leaders, many business owners in these states are conflicted about resuming business due to safety concerns.

Reopening the economy is aimed at helping struggling business owners, but many experts—including National Institute of Allergy and Infectious Diseases (NIAID) Director Dr. Anthony Fauci—have concerns that reopening will backfire if there is another spike in confirmed cases.

While experts have determined how the virus is spread and preventative measures to avoid infection, there is still concern about what we don’t know. Much of the current uncertainty is centered on the aftermath of coronavirus. What if a person has previously been infected and recovered? Do these individuals have antibodies that prevent them from contracting the virus twice? Here’s what the experts have to say.

Dr. Anthony Fauci, Director, NIAID; Discussing the Coronavirus Antibodies
Dr. Anthony Fauci, Director, NIAID; Photo Credit: NIH

There is no evidence that a COVID-19 survivor can’t contract the virus twice

A statement released on April 24 from the World Health Organization (WHO) reads, “There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.”

In fact, an increasing number of COVID-19 survivors have tested positive for the virus a second time, suggesting that just because you’ve already been infected, you’re not guaranteed immunity. Researchers and health officials are still learning about the coronavirus, understanding how long it lingers after initial infection, if there is a level of immunity after recovery and for how long, and what prevention—including vaccination—looks like in the future.

After the SARS outbreak, a closely related coronavirus to COVID-19, research showed that those who recovered from SARS had developed antibodies to protect from reinfection for approximately three years. COVID-19, however, is too new and there isn’t enough data to draw definite conclusions on antibody protection.

COVID-19 virus emerging from surface of cells cultured in the lab
COVID-19 virus emerging from surface of cells cultured in the lab; Photo Credit: NIH

Understanding COVID-19 antibodies starts with understanding how the immune system works

A viral infection begins when a virus attaches itself to and enters a cell in the body. It then hijacks the cellular process to replicate the virus, and those copies then spread throughout the body, enter new cells and continue replicating.

This is what the immune system works tirelessly to stop.

There are two sides to the immune system, the innate immune system (what people are born with) and the adaptive immune system (what is developed when the body is exposed to infections and viruses). The innate immune system is the first line of defense against viruses, springing into action at the sign of an invasion. When effective, the virus is killed inside these immune system cells or phagocytes. When it fails, the person gets sick.

The adaptive immune system, however, fights against specific pathogens that the body is exposed to. Antibodies are developed within cells called B lymphocytes after exposure to fight against reinfection. These antibodies “recognize and latch onto antigens in order to remove them from the body.”

But, antibodies don’t appear immediately and can take days or weeks to develop.

For coronavirus in particular, Vineet Menachery—an immunologist studying coronaviruses at the University of Texas Medical Branch—told Vox, “When you first get infected with SARS-Cov-2, it usually takes anywhere from 10 to 14 days to make antibodies that are effective. That immunity actually peaks between four and eight weeks after you’ve been infected. The antibodies are really powerful at that point.”

Research is ongoing, and it is still unclear if a person may develop an immunity to COVID-19 and for how long after recovery.

Antibodies testing
Photo Credit: Obi Onyeador

Although immunity is still unclear, serological tests have been deployed to identify who has developed antibodies

Serological tests—or immunity tests—were approved for use by the FDA earlier this month and test whether a person possesses antibodies to COVID-19. The hope is that these tests could help people get back to work. Those who show a presence of antibodies could potentially be issued antibody cards or immunity passports that would exempt them travel and distancing restrictions. The WHO cautions against this, however, stating in its scientific brief that there is no evidence that a person is protected from reinfection and that these serological tests need more validation to confirm their accuracy.

The WHO did indicate in its statement that many of the studies reviewed have shown that people who recovered from infection have developed antibodies to the virus. Some, however, have very low levels of neutralizing antibodies (the antibodies that bind to the virus to block infection) in their blood, “suggesting that cellular immunity may also be critical for recovery.”

Most notably, the WHO reconfirmed that “no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.” And, even with a current presence of antibodies, scientists can’t know at this stage if these may fade in a matter of months or years, leaving these people vulnerable.

While a definitive conclusion on immunity has not yet been reached, serological tests can provide scientists with a clearer picture on the pandemic overall. They can determine how many people have been killed by coronavirus, which survivors were asymptomatic and who may have unknowingly spread the virus.

People wearing masks to prevent catching the coronavirus or covid-19
Photo Credit: Obi Onyeador

There are still a variety of looming questions beyond antibody immunity

While serological testing continues to determine the presence of antibodies, scientists still don’t know a lot about potential antibody immunity. It is still unclear what level of these antibodies is needed in the blood to effectively immunize an individual. And, if the appropriate levels of antibodies are in fact present, how long will they remain in the blood? At what point will the person become vulnerable again?

These questions play into how scientists will develop a potential vaccine. The timing to deliver a successful vaccine is still variable, and it could take at least a year to develop. Investigation around convalescent plasma is also ongoing, using plasma from COVID-19 survivors to help those currently fighting the infection. This is also being considered for prophylactic use.

There is still plenty to learn about coronavirus, antibodies and preventative measures to avoid a future outbreak. Since the virus is so new, reliable data just isn’t yet available to definitively answer questions about immunity for survivors. As scientists administer more tests and gather necessary data, the best current prevention strategy is to continue to follow the Center for Disease Control and Prevention guidelines to avoid infection and spreading the virus.

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