One of the regulars on This Week in Virology (TWIV) is a clinician from Columbia Univ in NY. On (https://www.youtube.com/watch?v=LYo9oK-Giso)this week's show he mentioned that one of his 2 patients this week (0 last week!) was a physician who was PCR-positive in March (having symptoms, and along with his family) and he treated as an outpatient. Now, that patient is PCR-positive again but is having to be hospitalized.
He then mentioned another patient (not his) from Washington (DC or state??) that had been mentioned last week was apparently reinfected in the same time frame, again with being worse this time. (One of those two apparently thought he was immune and dealt with a son with COVID, leading to the reinfection.)
As they said, two cases are anecdotal.
All that said, when we see that NY has so few cases now (roughly 2000/wk) after having so much COVID before (roughly 30K/wk), is it chance, is it learned behavior, or is there a biological effect? It seems to me you don't need the percentage of (temporary) immunity to be high except in those that have wide exposure to other people. A lot of those people were sick in March & April (even if they didn't know it). TWIV mentioned in passing a seropositive rate of 68% for some front line people. Kinda like a flash wildfire that burns all the dry grass won't reoccur until there is enough dry grass again.
He then mentioned another patient (not his) from Washington (DC or state??) that had been mentioned last week was apparently reinfected in the same time frame, again with being worse this time. (One of those two apparently thought he was immune and dealt with a son with COVID, leading to the reinfection.)
As they said, two cases are anecdotal.
All that said, when we see that NY has so few cases now (roughly 2000/wk) after having so much COVID before (roughly 30K/wk), is it chance, is it learned behavior, or is there a biological effect? It seems to me you don't need the percentage of (temporary) immunity to be high except in those that have wide exposure to other people. A lot of those people were sick in March & April (even if they didn't know it). TWIV mentioned in passing a seropositive rate of 68% for some front line people. Kinda like a flash wildfire that burns all the dry grass won't reoccur until there is enough dry grass again.