What can we learn from COVID-19 in Fairfax, Florida, and Israel?

This article in Science Magazine, “A grim warning from Israel: Vaccination blunts, but does not defeat Delta,” details some of the recent data from Israel, one of the most highly vaccinated countries in the world. Israel also has some of the best real-time medical data in the world. It has also recently experienced an upsurge of COVID-19 cases due to the new Delta variant with a doubling rate of 7 to 10 days, comparable to what we have been seeing recently in Fairfax County. Although the vaccines definitely offer protection, they have not been sufficient in themselves to stop the new surge in Israel, and there have been many breakthrough infections, especially among older people who have less robust immune systems and who were vaccinated first (starting last December) and thus are longer from acquiring some immunity. Israel is turning to additional measures like a 3rd booster shots plus reinstating masking and distancing requirements to blunt the new wave.

Interestingly, the case rate per 100,000 people in Israel is 6 times higher that the current rate in Fairfax County but is still two times smaller than the high rate currently being experienced in Florida (to take an example state). Florida and Fairfax make a stark contrast: case rates per 100,000 are now around 10 times higher in Florida than Farifax. Current case, hospitalization, and death rates in Florida actually now all EXCEED the peaks that Florida experienced in their previous peak period last January and February. By stark contrast, Fairfax case rates remain six times BELOW their Februrary peak; furthermore, hosptalization and death rates in Fairfax remain near all-time lows.

The current death rate in Florida from COVID-19 is nearly 1000 per week, whereas in Fairfax it is only around 1 per week. Since Fairfax has a population 1/20th that of Florida (1.1 million versus 21 million), the Florida death rate per capita would scale to around 50 deaths a week in Fairfax if the rates were the same, which is 50 times larger than what Fairfax is actually currently experiencing. So Fairfax continues to do remarkably well compared to much of the rest of the USA, Florida in particular. Furthermore, recent data are showing that the rapid increase in cases in Fairfax is leveling and hopefully turning over (a couple more weeks of data are needed let us know for sure).

What is the difference between Fairfax and Florida, which have similar vaccination levels, 66 % for Fairfax and 62% for Florida with 1+ dose)? I can not know for sure, but can hazzard a guess and an editorial opinion. People in Fairfax continue to make wide use of masking and distancing in public places, especially indoors, and thus to a significant extent still are taking a variety of sensible precautions against getting COVID-19. Fairfax County now requires masking in its public facilities and recommends it in any indoor public setting. By contrast the Florida governor and his allies there have been hostile throughout the pandemic to masking and other precautionary measures that are proven to be effective measures against disease spread. They are especially needed to blunt Delta.

Why does masking help? Let’s do some simple arithmetic. Assume masks prevent 3/4 of virus droplets from being inhaled or exhaled, so only 1/4 of them get breathed in or out (some masks will be much better than 1/4 reduction, some worse). If you wear a mask and have COVID, I am exposed to 1/4 less virus. If both of us wear masks, I am exposed to 1/4 x 1/4 = 1/16 less virus. For a highly contageous virus like Delta, reducing exposure 16-fold makes a really big difference. States with mininal masking are going to be far worse off than states with maximal masking, even if vaccination levels are the same. This follows from a scientific knowledge of the dominant indoor airborne transmission mode of the virus and the effectiveness of masks in reducing viral load. Simple prevention steps like masks indoors and distancing (everywhere) make a real difference.

Here is my editorial comment.

I have no desire to offend people, but I do not want people to die when there is a better way. To my thinking, the Florida governor is not being responsible, and his unsound policies are a contributing cause to the needless deaths of thousands of the citizens of his state. This is not about a current controversey over schools–it goes back over more than a year regarding pandemic control policies for the general public across a range of activities. It rouses my sense of righteous anger to see politiciams or other public officials acting in the direct opposite way to sound scientific/medical counsel. I will try to counter them with good scientific data and analysis to the extent that I can. I hope to save lives that way. End of editorial. You can make up your own mind.