2020.10.15 The Seattle Times

The Seattle-area nursing home resident first tested positive for the novel coronavirus in early March. He spent more than 40 days in the hospital with fever, pneumonia and difficulty breathing before testing negative multiple times and being discharged.

Then, nearly five months later, he got sick again with COVID-19.

Now, genetic testing by a team of Seattle physicians and scientists has revealed that sexagenarian’s second bout of the illness caused by the coronavirus in July wasn’t a relapse but a new infection with a slightly different variant of the virus.

The patient is only the third person in the United States — and one of about 20 worldwide — confirmed to have experienced such a double whammy.

Since posting a preprint in late September describing their findings, which have not been peer-reviewed, the Seattle team has confirmed one additional local reinfection and is examining a handful of other possible cases, said Dr. Jason Goldman, an infectious-disease specialist at Swedish Medical Center.

“It’s not unexpected this would occur, because we know immunity wanes to other respiratory infections, like flu,” Goldman said. “But I was a little surprised to find it in my own hospital.”

Scientists are still trying to figure out the significance of the cases, but it’s reassuring that reinfection seems to be rare, Goldman said. That indicates most people develop a protective immune response after infection, though how long it lasts remains unclear.

“And we still don’t know what level of immunity you need to be protected,” he said.

The local patient wasn’t as sick the second time around and has since recovered, which suggests some level of protection even if it wasn’t strong enough to block infection, Goldman noted. That seems to be the case for most reinfections reported so far, he added.

But for a handful of patients, including a 25-year-old Nevada man whose experience was first made public in August followed by a full report published this week in The Lancet, the second infection was more severe. An 89-year-old woman in the Netherlands, who was also undergoing chemotherapy for lymphoma, is the first person known to have died from a repeat infection.

According to a site that tracks reinfections around the globe, the other U.S. case was a 45-year-old man who works at a military hospital in Virginia and who also was much sicker during his second bout with the virus.

Building on a collaboration between Swedish Health Services and the Seattle-based Institute for Systems Biology (ISB) to assemble a vast “biobank” of health data from COVID-19 patients, the Seattle team performed the most detailed analysis yet of a patient’s immune response to a second infection.

Some documented reinfections have occurred in people with compromised immune systems, like the Dutch woman who died. The Seattle-area patient also suffers from emphysema, and was treated with steroids, which can dampen immune response, Messer pointed out.

“There’s probably something about this patient’s immune system that isn’t really functioning well,” Goldman agreed.

But because no blood samples were stored from the man’s first infection, the researchers weren’t able to compare the two immune responses.

Read More