In both Bergamo and Manaus, the number of Covid-19 cases has tailed off dramatically, possibly as a result of herd immunity curtailing the virus’ spread. But there are several reasons that this is ordinarily achieved with vaccines – and why it’s unusual to discuss the concept in the context of natural infections.
อ่านต่อเพิ่มเติม โรงเรียนบ้านร่องเจริญ
สาระสำคัญ นมแม่
