来自推特以及中国的文章
The antibody story to #COVID19 is not simple:
1. Some people w/ infection don't develop much IgG (it's about level,
-hello717(Happy);
2020-4-8{249}(#12843809@0)
not just 0|1)
https://scmp.com/news/china/science/article/3078840/coronavirus-low-antibody-levels-raise-questions-about…
2. People w/ IgG may still spread (not neutralizing) or get reinfected
3. Duration of Ab/protection is unknown (months/yrs?)