Fewer than 1 in 10 Americans show signs of past coronavirus infection, large national study finds

This suggests millions may still be vulnerable to infection, authors say

 https://www.washingtonpost.com/health/2020/09/25/coronavirus-immunity-us/?utm_campaign=wp_post_most&utm_medium=email&utm_source=newsletter&wpisrc=nl_most&carta-url=https%3A%2F%2Fs2.washingtonpost.com%2Fcar-ln-tr%2F2bc5fff%2F5f6f67649d2fda0efb359eab%2F596c0405ade4e24119c0f2a4%2F21%2F60%2F0d4656ed000fda3a72d954764b5ee4e5