Internal documents exchanged among scientists at the CDC indicate that the delta variant is both more transmissible and more virulent than previously suggested. Where most public estimates had put the rate of reproduction around 6, this document places delta as similar to chickenpox where each person infected might be expected to pass the disease to 10 or more others. And, on top of that stomach-dropping number, the document also warns that delta is more capable of causing severe illness.

As The Washington Post reports, the document is actually a slide deck prepared for sharing within the CDC. To say that the document is urgent is somewhat underselling it. The point of the presentation is that “the war has changed,” and that the delta virus is so transmissible, so dangerous that it needs to be treated like a whole new virus. Included in the document are results from studies that are still unpublished, but whose early results are grim.

Friday, Jul 30, 2021 · 3:40:06 PM +00:00 · Mark Sumner

Some good news … 


One of the factors discussed is that, while vaccinated individuals tend to have less severe illness from the delta variant, they can pass the virus along to others. That has been suspected for weeks and formed part of the background for recent changes in CDC recommendations involving vaccinated individuals wearing masks, but the concern revealed in the document is that existing messaging—one that has suggested that vaccinated individuals should be allowed privileges not given the unvaccinated—are inaccurate when it comes to stopping the spread of delta.

“Sobering,” is one way to describe the document. “Frightening” also works. And what it definitely shows is an agency desperately searching for the right way to deal with an unprecedented crisis.

From the beginning, the CDC has had the extremely unenviable task of trying to design guidelines against a disease that is, as the original name suggested, completely “novel.” The action of the virus, the pathway that it uses in attacking human cells, how it spreads from person to person … all of that was an unknown at the outset. Even so, the CDC had to provide instructions on how the nation should address the threat. It certainly didn’t help that, at the outset of the pandemic, that guidance was heavily distorted by political pressure from a White House intent on downplaying the threat at every turn.

Advice has shifted over time as more information has come in, but the advice from the agency has also been affected by pressure from businesses that pushed back against restrictions, by parents who wanted their kids back in school, and by politicians eager to please both. Pair that with a shifting understanding of how the virus spreads—droplets? surfaces? aerosols?—and wrap it all in a big case of “we don’t know.” We don’t know how many people will suffer long-term damage. We don’t know how long those who have been previously infected are protected against reinfection, even by the same variant. We don’t know how long vaccines will last. The CDC is stuck giving the best advice it can give, or at least the best advice it is allowed to give.

Even when the agency does act, its advice had been rendered toothless by a previous White House that took exactly zero actions on the basis of its recommendations. How long did America go into lockdown? It didn’t. When did America shut down the schools? It didn’t. What were the rules on the mask mandates? There never was one. Everything was left to state and local authorities to interpret, creating an absolutely unworkable hodgepodge of rules that might as well have been designed by the virus itself.

All of this has the effect of not just increasing distrust among those already inclined to believe in anti-vax plots, but of making even those most inclined to support the experts at the CDC suspicious of their veracity. For good reason. 

Right now, the agency is spreading a message on masking that backs away from the theme that the unvaccinated can go about their business as normal, but only just backing away. Meanwhile, internally the message is much more simple: “Given higher transmissibility and current vaccine coverage, universal masking is essential to reduce transmission of the Delta variant.”

A disease that has an R0 of 10 or 12 cannot be stopped unless there is a very high level of immunity to that disease. Right now, the CDC indicates that 49.4% of the U.S. population has been fully vaccinated. According to the official numbers, about 11% of the population has been infected by the virus. That second number is surely a large underestimate, but there are also overlaps between those who have been infected and those who have been vaccinated, so the assumption that around 60% of the population has some level of immunity to SARS-CoV-2 may be pretty close.

However, if those who have been previously infected by other variants of COVID-19, as well as those vaccinated, can still pass along the disease, the effective level of resistance to the delta variant is 0%. Assuming that the vaccines both reduce the chance of infection, and reduce the chance of passing along an infection, that number might be cranked up. But the safer thing is to assume it doesn’t.

The good news out of all this is that vaccination still does appear to give good protection against severe illness caused by the delta variant. That’s a very good thing, because the other big indication from the internal document is that illness produced by the delta variant is more likely to be severe among the unvaccinated.

As vaccine expert Dr. Kathleen Neuzil expressed when speaking to the Post, getting people vaccinated remains the priority in protecting the nation, but when it comes to delta, “We really need to shift toward a goal of preventing serious disease and disability and medical consequences, and not worry about every virus detected in somebody’s nose.” And, according to Neuzil, “It’s hard to do, but I think we have to become comfortable with coronavirus not going away.”

That advice may seem like tough love, but it may also be impossible. The simple fact that the delta variant is so much more contagious than previous variants, is able to cause breakthrough infections among the vaccinated, and is so capable of causing more severe illness shows that this novel virus is just getting started. Many of those in the “COVID-19 must have been engineered” camp have pointed to how infectious the virus was at the outset and concluded that steps must have been taken to make SARS-CoV-2 so effective in attaching to human cells. But the opposite conclusion may actually be more frightening—if the original “wild” form of the virus was exactly that, there has been an incredibly rapid progression demonstrating an enormous possibility for “improvement” in the sense of creating something worse.

For the moment, the message of getting everyone vaccinated to protect against deaths caused by delta is a good one. But it can’t be the final message. Because there is absolutely no evidence that this virus is something we can learn to live with, and a massive amount of evidence that we are something this virus is still learning to kill.

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This is a Creative Commons article. The original version of this article appeared here.


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