Can You Get COVID-19 Twice? The Science Says…Coronavirus (COVID-19)
Eight months into the COVID-19 pandemic that has killed more than 440 people in Lee County and infected more than 19,000 others, the question on many of our minds has been: Can you get COVID-19 twice? (Figures as of Sept. 9, 2020)
Like with so many other questions we have about COVID-19, the answer isn’t clear.
On Aug. 24, researchers in Hong Kong confirmed a 33-year-old man was infected a second time with COVID-19 more than four months after his first bout.
The patient was first diagnosed with COVID-19 in March and cleared the virus in April, according to the study.
In August, the man tested positive and hospitalized, but remains asymptomatic.
Antibodies: What Do They Mean?
The body's immune system fights infections by producing antibodies to viruses, and some experts think that those who recover from COVID-19 develop antibodies that may offer protection against reinfection.
But how strong that immune response is and for how long it lasts remains unknown.
Top infectious disease experts assert that immunity to other known coronaviruses, including those that cause the common cold, typically lasts only 3-6 months.
The Hong Kong reinfection study, slated for publication in the medical journal Clinical Infectious Diseases, details how researchers sequenced the genomes of the virus after both infections for comparison.
Researchers found the second infection appears as a slightly different virus strain from the initial one, thus confirming reinfection, rather than a positive result due to a lingering first infection.
Nevertheless, Dr. Stephanie Stovall, infection prevention medical director with Lee Health, says we shouldn’t stress about the reinfection case.
“To date, there’s been more than 24 million cases of COVID-19 worldwide,” Dr. Stovall says. “This is the first documented case of reinfection, and many scientists expected that we could see COVID behave this way.
“We see this with other types of coronaviruses, the ones that give us the common cold. It is unknown if the genetic differences that were seen will affect immunity.”
It’s remains unclear how common reinfection from COVID-19 might be because few researchers have sequenced the virus from each infection, Dr. Stovall adds. That's a reminder that COVID-19 is a new disease, caused by a new coronavirus previously unseen in humans.
Dr. Stovall cautions that the Hong Kong study is in “pre-print” status, meaning its findings must first undergo rigorous peer-review and consensus by scientific experts before Clinical Infectious Diseases grants manuscript acceptance.
What About a Vaccine?
Nevertheless, Dr. Stovall says the finding may offer potential implications regarding the development of herd immunity and possible vaccines.
“In the Hong Kong study, this individual had milder illness (reportedly asymptomatic) with his second infection, which may be a positive sign if COVID vaccine was developed that could replicate the same immune response,” Dr. Stovall explains. “Ideally, vaccines would completely prevent infection, but they’re also beneficial if they keep patients out of the intensive care unit or, even better, out of the hospital.”
Dr. Stovall says the patient became re-infected relatively soon (4.5 months) after clearing his first infection, and this suggests that long-term immunity may not be naturally occurring after infection.
“For example, people who have had a virus like the measles develop lifelong immunity (along with antibodies) to it,” she explains. “When we’re re-exposed to the measles, special white blood cells called B lymphocytes in our immune system start producing antibodies that neutralize the virus and mark it for destruction by other types of white blood cells.”
With COVID-19 and “common cold” viruses like other coronaviruses and rhinoviruses, our bodies may develop detectable antibodies, according to Dr. Stovall. But there is the possibility that these antibodies either don’t last long enough or aren’t strong to prevent reinfection.
“This may mean that the concept of herd immunity is less likely to be effective at controlling disease in our communities,” Dr. Stovall notes. “Ultimately, we need more information from vaccine trials and from the genetic sequencing of the virus in suspected re-infection cases to know more.”
Until more evidence-based data become available to bolster the fight against COVID-19, wearing a mask, practicing social distance, and regularly using alcohol-based hand sanitizers remain the answers that we can count on.