Michele Hart, of Layafette, Colo., first tested positive for COVID-19 on May 2.
She told KUSA-TV in Denver that her symptoms have “come and gone” but she thought she had fully recovered when two consecutive tests came back negative.
She said some of her symptoms wouldn’t go away so she went to urgent care thinking she might have contracted the flu or strep throat.
She tested negative for both but positive for coronavirus Wednesday.
“This virus is just so new we just don’t have enough data,” KUSA health expert Dr. Payal Kohli said. “And I really like to call this virus the wildcard virus because it’s done so many things that have surprised scientists on so many levels.”
Kohli said Hart’s case shows that some patients may never develop antibodies against the virus, but, he added, not developing antibodies is rare.
Another possibility, Kohli said, is that the virus became dormant then reactivated like chickenpox or it’s possible she “never completely cleared viral particles” and never fully recovered.
As scientists continue to work toward a vaccine that could be a year away, some have hoped herd immunity – when a majority of people have become immune to the virus through surviving it or getting a vaccine – could help slow the virus’ infection rate, but patients getting reinfected could complicate that.
The Centers for Disease Control and Prevention has advised there’s no guarantee having the virus will give a patient immunity.
Other coronavirus patients in the U.S. have also tested positive after recovering, including 14 sailors on the USS Theodore Roosevelt who tested positive again after meeting “rigorous recovery criteria,” a U.S. Pacific Fleet spokesperson said in a statement.