Any seasonal rise in COVID-19 infections has not happened yet.

Today, we were inundated with a rash of news reports warning of potential increases in COVID-19 cases this fall. Again, the rationale is that as people spend more time inside because of colder weather they will be more likely to transmit the coronavirus between themselves. 

In response to these reports, I decided to focus on our weekly review of the statistics of COVID-19 in the United States. They contain much good and concerning information, including the sad news that the overall death toll in the US has reached 200,000. However, the bottom line is that while there is concern for an increase this fall it has not yet occurred, and rational steps, including wearing masks and social distancing, could negate any seasonal increase. 

When one looks at the COVID-19 numbers in the United States overall this week, the most disconcerting thing is that the number of new cases appears to either be stable or slightly increasing. This suggests that the reductions from the summer’s peak that had occurred through July, August, and early September have stopped. Despite this, the number of deaths has continued to drop. In fact, the United States’ position among other nations in terms of new infections and total deaths per capita is at its lowest point in several months.

The US is now 10th in total cases per capita and 9th in total deaths per capita.  These decreases appear to be related to the decreases in United States infections and deaths, but also to the marked increases in COVID-19 cases in South America and in Europe. 

Top 15 states with the most new COVID-19 cases.

It is interesting that the states with the most new cases are not in the northern climates where temperatures are turning colder. The top three states are Texas, California, and Florida that have maintained top spots for a number of weeks. While the overall number of their cases has fallen, these three states continue to show the most substantial number of infections. In particular, Texas is remarkable in having almost 10,000 new cases the past day, dwarfing the number in any other state. 

Among the top 15 states, several have chronic problems with COVID-19 infections. This includes Wisconsin, Illinois, Pennsylvania, and New York. Therefore, there is no indication that the driving force of infections in these states is the change in weather during the fall season. That doesn’t mean, however, that the large numbers of infections in several of these states won’t grow worse because of seasonal increases in infections later this fall. 

R0 numbers for the 50 US states today, September 22, 2020.

In addition, the Rnumbers (or degree of transmission) for COVID-19 in the 50 states have not changed significantly over the past 2 weeks, although they have increased overall from 4-6 weeks ago. Again, there is no focused increase in northern states where the weather has turned colder. In fact, some northern states, such as North Dakota, Michigan, and Ohio, have had significant decreases in new infections.

Therefore, as we enjoy the fall foliage we need to be vigilant for further increases in infection, but aware that as of yet there is no “seasonal” bump in COVID-19.

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

2 thoughts on “Any seasonal rise in COVID-19 infections has not happened yet.

  1. This is great news for the country, but this does not reflect the numbers in my area which have shown a bump in numbers the last 3 weeks in my county in PA.


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