Delta Blues
variant that overwhelmed India threatens the West
July 29th 2021
Three states totaling one fourth of the US population made up 40% of new cases of COVID-19 last week. All were in the South, all were heavily Republican, and all had very low rates of vaccination against COVID. Even more dismaying, over 80% of new cases were the Delta variant.
There is more news about the Delta variant, and most of it is pretty bad. First, there’s the matter of the transmission rate. It has an R0 between 5 and 8, which means that an infected individual can be expected to infect between 5 and 8 susceptible individuals. For comparison, the Alpha variant had an R0 between 4 and 5. A report by the Washington Post tonight suggest the R0 estimate may be revised upward, which is catastrophically bad news.
When the R0 is four, this is how it can spread: If you infect an expected four people, and each in turn infects 4 more, that’s 20 people. Those sixteen new cases go on to infect 64 more. Those 64 infect 256 more. It’s exponential growth, and the numbers grow very rapidly.
But if the R0 is eight, then one person infects 8, they in turn infect 64, they in turn infect 512, and they infect 4,096. Same number of stages of growth, but one number is eight times as high. The gaps widens exponentially. The gap is 16 times as high in the next stage.
By way of comparison, the flu has a R0 between 1.3 and 1.6, depending on the strain. In a typical flu season, millions get the flu, thousands die, although vaccines are causing a drop in those numbers. (Because of social distancing, a happy side effect was that “flu season” last winter was the smallest in at least 100 years). The common cold has an R0 between 2 and 3, and yet nearly everyone gets at least one cold in a given year. Of course, there’s hundreds of strains of virus out there that cause the cold, and it’s just a part of our lives. But those R0 rates should scare any one capable of doing simple arithmetic.
Rubella, which is notoriously contagious, has an R0 of 6 and 7, making it essentially as infectious as the Delta variant. The mumps, which used to routinely wildfire through entire school districts, has an R0 of 10-12. So does chickenpox. The regular measles has an R0 of 12-18.
It gets worse: people who have received both shots, either Moderna or Pfizer, may only have an 8-10% chance of being infected with the Alpha variant and are considered fairly low risk to carry it on. With the Delta variant, the chance of infection is higher, although it is yet to be determined how much higher. The one bit of good news is that 90% of those with vaccines will have mild or non-existent symptoms. However, they “virus load” (i.e. become as contaminated) as non-vaccinated people, and can pass the disease along to nearly all unvaccinated and an unknown but sizable number of vaccinated people.
When I was a kid, measles, mumps and chickenpox were very nearly inevitable, and sometimes killed kids. I’m glad they are part of our past, along with diseases like polio and smallpox.
The elephant in the room is “long COVID”–a galaxy of aftereffects that range from annoying to debilitating. Respiratory issues, vascular problems, “brain fog”, fatigue and susceptibility to other diseases. It is known to show up in people who remained asymptomatic in the initial stages of the disease. We have no clear idea how or even if it manifests in people who have gotten their shots and become infected. It may take years before we really do know. But the threat is there.
So if you have your shots and you’re swanning around maskless, stop doing that right now. What for you might be nothing worse than a mild cold could mean potentially significant health issues for you in the future.
You will also be a deadly threat to anyone you encounter who hasn’t been vaccinated. If you infect 8 people and they infect 64 and they infect 512, the odds are you just killed a half dozen people, and hospitalized about 24 others.
So mask up and observe social distancing. Yes, we’re all sick to death of it, and furious at the fools who won’t take steps to defend themselves and everyone else, but unless we want America to be the first country to stupid itself to death, we need to keep taking these steps and hope our social recklessness doesn’t open the door to even bigger medical problems.
Mask up. Keep your distance, and if you haven’t yet, get your shots. Over 163 million have, and it’s clear they are safe and effective. And yes, Delta variant is effective in its own way, but it sure ain’t safe.
Stay safe, exercise better sense than a squirrel on the freeway, and we’ll get through this.
