A first case of #COVID19 reinfection from HKU, with distinct virus genome sequences in 1st and 2nd infection (142 days apart). Kudos to the scientists for this study.

This is no cause for alarm - this is a textbook example of how immunity should work.

(1/n) https://twitter.com/cwylilian/status/1297830744509698050

1) Second infection was asymptomatic. While immunity was not enough to block reinfection, it protected the person from disease. (2/n)

2) Patient had no detectable antibody at the time of reinfection but developed detectable antibody after reinfection. This is encouraging. (3/n)

3) Since reinfection can occur, herd immunity by natural infection is unlikely to eliminate #SARSCoV2. The only safe and effective way to achieve herd immunity is through vaccination. (4/n)

Lastly, while this is a good example of how primary infection can prevent disease from subsequent infection, more studies are needed to understand the range of outcomes from reinfection. (end)