In August 2021 (Left panel below), at the beginning of the Delta variant wave, infections surged in the southeast United States. These areas had the lowest vaccination rates leading to some of the highest spread of infection. Hospitals in Florida, Mississippi, and Louisiana were overwhelmed with patients, and deaths increased to levels not seen since December 2020, before vaccines were available.
Now, in November 2021 (Right panel), we are seeing almost an inversion of new case rates. Cases are surging in the northern states and have fallen off in the southeastern states. While overall vaccination rates have approached 70% across the country, infections seem to be most common in areas with high rates of unvaccinated individuals. There are several messages to take home from this change.
Clearly part of what is happening is that many, perhaps most, of unvaccinated individuals in the Southeast have become infected with COVID 19. Clearly, immunity that occurs post-infection, along with increases in vaccination triggered by concern from the Delta surge in this region have reduced transmission in many of the hardest-hit areas of the Southeast.
The infection is now spreading predominantly in unvaccinated individuals in the North and West. This has been triggered by several events including return to school in September and October, as well as people starting to congregate indoors as temperatures get colder in northern climes. People who might have smugly looked at Florida or Louisiana and thought that it won’t happen elsewhere are being proven wrong.
While some may view this as a victory for “natural” immunity, a few points need to be made.
First, due to increased overall vaccination rates in adults, overall infections in the U.S. continue to drop despite the uptick in northern and western states. In addition, deaths also continued to drop, again likely due to the vaccination rate and the fact that infections are now occurring in younger individuals and children.
Second, it is also important to remember that the “natural” immunity that was gained from infections in the southeastern United States came at a terrible cost. The number of deaths there exceeded all but the worst COVID-19 death peak in December 2020 before vaccines were available. They are still elevated, in part because we are providing better care for many of these younger patients, and it is taking longer for them to die.
Third, health systems in the Southeast are still trying to recover from the impact of this surge, and many normal medical activities and procedures have been delayed or missed entirely. This will have long term wellness implications, made worse by long COVID-19 and other post-infection problems.
In addition, infections in children do appear to be problematic in terms of overall spread to unvaccinated adults, and this has been demonstrated in Europe (particularly in Britain) where school transmission has been responsible for much of the new wave of COVID-19.
Overall, COVID-19 will not go away until essentially everyone is immune, either through vaccination or post infection. I believe that will happen over the next six months, but I also know that it would be a much easier road for everyone if people were vaccinated rather than trying to gain immunity through infection. I think almost everyone involved in health care who has observed the damage that this infection causes would agree.