There are probably multiple reasons why coronavirus cases in the US are down nearly 50% in the US in the last month. Could be seasonal. Could be the vaccine. Could be herd immunity from natural infection. Could be the post-holiday default to endemicity. Could be a change in the cycle threshold of PCR that generates fewer positive cases. Could be data tweaks in light of political changes. Anyone who says he knows for sure which is dominant is pretending to know the unknowable. The New York Times, which obliquely reports the case decline, is still certain that you should still...