The takeaway in that tweet is that there’s still no substantial evidence that warmer temperatures are going to “significantly” slow the rate of spread of CoV-19 especially to the point where it basically dies off. I think it’ll be too little too late in any case for the US because the outbreak is well underway here. If the virus relents, which I think it very well could, we will probably see that some time in the summer & that’ll largely be due to a decreasing number of potential non-infected hosts and preventive measures that are already beginning to occur, with more significant ones probably forthcoming (shutting down businesses, travel, etc, etc.) and not due to warmer temps. There’s definitely concern that another outbreak will come knocking this fall and it remains to be seen how virulent said outbreak may be.