Another repeat infection with SARS-COV-2, this time in US: 25 y/o man with distinct virus genome 2nd time

This paper, a pre-print (not peer-reviewed yet) in Lancet (abstract here), describes a man who had two infections with genetically distinct SARS-COV-2 isolates resulting in two symptomatic episodes of COVID-19. From the paper:

In April, 2020, a twenty-five year old resident of Reno, NV tested positive for SARS-CoV-2 through a community-based testing event held by the Washoe County Health District (collection date: 4/18/2020). The patient indicated symptoms consistent with viral infection (sore throat, cough, headache, nausea, diarrhea; onset: 3/25/20). During isolation, the patient indicated resolution of symptoms (4/27/20).

(from pdf version)

Forty-eight days later (on 5/28/20), only two days after testing negative for the viral antigen, the patient had a recurrence of symptoms. He was hospitalized with hypoxia a few days later. Chest imaging showed pneumonia. This time (on 6/6/20) he had an IgM/IgG positive blood test. The virus responsible was found to be genetically distinct from that isolated during his first episode.

The details of the distinction are complex, but the viruses were in the same clade (strain) but there were several mutations in the second isolate which were not present in the first. In addition, the patient’s parent had symptoms simultaneously with the patient’s second infection and was found to be positive for SARS-COV-2. At the time of publication, the authors were unable to confirm the identity of the second infection with that of the patient’s parent (but they’re working on it.)

This patient had no immunosuppressive conditions and was not on any medication which might have prevented him from resisting the second infection.

This and other, so far isolated, cases of re-infection with different strains of the virus represent confusing, not to say bizarre, facts about this new virus. Speculation would be premature at this juncture.

Suffice it to say that it is possible for young, healthy people to be infected a second time within a few months– and to have significant symptoms and disease (pneumonia in this case.)