Scientists confirmed this week the first reinfection of a coronavirus patient in the U.S. — a 25-year-old man in Nevada.
The Washoe County resident tested positive for SARS-CoV-2, the virus that causes COVID-19, on April 18 and again on June 5, with two negative tests in between in May, according to a study published in the Lancet on Monday. The patient’s second infection was more severe than his first, and a genetic analysis revealed significant differences between the coronavirus strains.
“Previous exposure to SARS-CoV-2 might not guarantee total immunity in all cases. All individuals, whether previously diagnosed with COVID-19 or not, should take identical precautions to avoid infection with SARS-CoV-2,” say the study researchers, who hail from different institutions in Reno, Nevada.
The patient began experiencing viral-like symptoms including sore throat, cough, headache, nausea and diarrhea on March 25. On April 18, he tested positive for the coronavirus at a community testing event and was quarantined. His symptoms were gone on April 27, and he continued to feel well until May 28.
On May 31, the patient visited an urgent care center for similar symptoms and had a chest radiography done before being discharged home. His chest radiography showed signs of viral pneumonia.
Five days later, a primary care doctor found the patient to be hypoxic with shortness of breath. The patient, who had no history of underlying conditions or compromised immunity, had to visit the emergency department for oxygen support.
There have been other reports of secondary infections with SARS-CoV-2 from Hong Kong, the Netherlands, Belgium and Ecuador. While the patient in Ecuador also had a more severe disease the second time around, the reinfections elsewhere were not more serious than the first.
A person’s immune system, in theory, should make antibodies after the first infection to help protect them if exposed to the same virus again.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University who was not involved in the study, said he is “completely flummoxed” as to why the second infection was more severe for the Nevada patient than the first.
He called the study an “exquisitely well-documented second case” of infection and not a relapsed or continuing first infection that recurred.
“It joins a less than handful number of reasonably well-documented cases and so it still is pretty unusual,” Dr. Schaffner said. “In fact, it’s very unusual, but it’s also very difficult to be in a circumstance where you have all the scientific resources available and all the specimens available so that you can rigorously document a second case.”
The study researchers noted it is possible that the patient had a case of continuous infection that deactivated and then reactivated.
Another possibility, they say, could be co-infection where the patient was infected with different strains of the virus. But for the speculation to be true that would mean the patient was infected with virus B type that went undetected in April and then virus A type became depleted before the June test.
What the confirmation of a second infection foretells is unknown, Dr. Schaffner said.
“We don’t know whether this is an odd singular event. Even second cases of measles have been well documented, but they are spectacularly rare,” he said. “We know so little about COVID and its immunity that we’re less certain about this. We don’t know if this is something that will remain distinctly unusual or if it will tell something more ominous down the road, ominous in the sense that there may be a substantial number of people who have second infections.”
That means that immunity built up from the first infection may not be “very durable” for a proportion of the population, he said.
Although scientists have recorded different strains of the coronavirus, drugmakers are using the coronavirus’ antigen, the spike protein, which has remained stable, to make vaccines. But how much protection and for how long immunity lasts that vaccines provide is yet to be determined.
Copyright © 2020 The Washington Times, LLC.