The Covid Tracking Project Tuesday showed the R-0 for the coronavirus in the US \u2013 that is, the number of new coronavirus infections that stem from a single case \u2013 is now below one in most of the country. In other words, one case of the virus now leads to less than one additional case on average in much of the country. While the news is cause for optimism among medical professionals, those same experts are warning that\u2019s it\u2019s still early in the reopening process to draw any larger conclusions. ABC News' Aaron Katersky has insight and joins Tony.