是病毒毒性低緩解了.walgreens前幾個月報道打疫苗後感染情況.BA.5已占美國covid病例近 90%.

https://weibo.com/ttarticle/x/m/show/id/2309404768238494941253?_wb_client_=1

https://www.nbcchicago.com/news/local/ba-5-symptoms-to-watch-for-and-more-information-about-americas-most-prevalent-covid-variant/2911927/