Note; The light blue in the graphs are the numbers of cases or deaths each day, measured on the y-axis on the left. The y-axis on the right is a measure of the rate of change over time.
I had been a bit surprised and puzzled at the relatively sudden rise and drop in cases in July in the US this summer.
I had been considerably worried that this marked the next resurgence of the disease. However, there are a few behavioral, administrative, and environmental variables that explain this decrease.
As some Americans began to see the rapid rise in cases accompanied by the hospital bed shortage problems that followed in AZ, CA, FL, and TX, they likely began to take the disease and precautions more seriously, including mask use and maintaining distance.
These changes were accompanied in some areas by administrative restrictions that reinforced these behaviors, including mask mandates, business capacity maximums, and other restrictions.
A big contributing factor in the decrease was the summer weather. This brought the population outside, where it was easier to maintain distance from each other and acted to dilute and virus particles that may have been in the air. In addition, the increased humidity of the summer reduced the chances that viral particles would remain suspended in the air.
The biggest contributor to reduced cases, hospitalizations, and death though was the shifting demographics of those infected. Summer weather also likely played a role in this. Teenagers and young adults spent more time together as schools and universities were out over the summer. Many young adults congregated at beaches and bars. Since this demographic would have milder illness, they would have been less likely to be tested, to be hospitalized, or to die than if this were equally distributed across the population as a whole.
Fall and Winter
Most of the dynamics that reduced cases over the summer are changing now. One way to see some supporting evidence of this is to look at countries that experienced winter over the past few months in the southern hemisphere.
This is also supported by the resurgence of cases now in Europe and North America as the weather cools, humidity drops, school starts, and people spend more time indoors.
Another factor that can be increasing the spread globally is pandemic fatigue. People are getting tired of the added precautions and restrictions, especially when it superficially appears that things are back under control. There is also some related danger in having created some good habits and reacting automatically instead of thinking things through. Even though I completed my board certification in healthcare infection prevention, I catch myself making mistakes. They are not intentional, and perhaps just because I’m getting very worn out from this brutal year. Fortunately, they have been small ones that were relatively low risk, but given that I know the prevention field like the back of my hand, it concerns me that those with only a cursory understanding of all of the components one needs to consider are doing this correctly. In 1984, during The Troubles in Ireland, the IRA made a statement that could apply if COVID could speak: “Today we were unlucky, but remember, we only have to be lucky once. You have to be lucky always.”
Even though this is a very different family of virus than that of the Spanish Flu in 1918, there is a lesson to be learned there as well. When it emerged in the spring of that year (most likely in Kansas), it caused what had been a typical bout of influenza. However, it mutated over the summer into something much more deadly. I’m not at all indicating I’m expecting that to happen with CoV, but the timing of the resurgence should serve as a warning. The Spanish Flu had it’s worst hit in the fall in major cities in the northern hemisphere.
The other major difference between 1918 and now is transportation. The disease moved pretty quickly across the country at that time in the course of a month, at a time when long distance travel was by train and cars were less common. Now, people can (and even do) travel across the country in hours, further promoting spread among different areas. During the emergence of H1N1 in 2009, NEJM published an article implicating the airlines in the global spread of the virus.
We are also at a mathematical risk compared to earlier this year. We are building back up to a higher number of baseline cases in comparison. As children and young adults return to school and potentially cause more community spread among other age strata, the need for hospitalizations and potential deaths increases. That increased baseline is especially important when thinking about this from an exponential spread standpoint.
We are still at risk of overwhelming our healthcare delivery system. Where this had been limited to urban areas due to population density, the virus has had more time to spread in more rural areas, where hospital beds are fewer, or don’t exist at all in some counties. As hospitals go beyond capacity, that also means that those who need care for other conditions may not be able to get it.
In addition, our pharmaceutical supply chain is at risk. Around 70-80% of the pharmaceuticals used in the US do not originate here. Many of the raw materials are shipped from China to India, where they are manufactured into the final consumer product. India is surging toward 100,000 new cases EACH DAY, which could adversely reduce production if left unchecked.
The other problem is related to how those pharmaceuticals arrive in the US. Traditionally, they arrive in the cargo holds of passenger flights. As this continues to resurge, those flights are likely to become less frequent, and alternate means of transportation may need to be established.
Back at the point of use though, there are shortages related to the virus. Some of the medications used to treat infections have been in short supply. One of these, albuterol, is used in inhalers to treat asthma. That could drive some dire consequences for those with asthma if the global supply is used more quickly than it can be manufactured.
We have a cultural problem in the US to combat this disease. Science denial is common, conspiracy theories abound, and compassion for others seems to have been forgotten. Those could become a deadly cocktail for our country.
For example, it’s mind boggling how people can think that this will become a non-issue after the election. I don’t know how anyone can possibly believe than about 800,000 deaths outside of the US could possibly be faked or part of a big conspiracy to influence our vote.
Unless people quickly learn to accept science and medicine, develop critical thinking skills, and learn to empathize to others, we are in big trouble.