COVID-19: Delta is not a delta…

Boy, it has been awhile. I’m sorry it’s taken me so long to write. Frankly I’m sick of this pandemic; surely you are as well. (Your response: I am sick of this pandemic, and don’t call me Shirley.) 

Seriously though, I’ve received a number of requests lately to give my take on the COVID-19 Delta variant and frankly, as one reader said, she needed my blog to calm her down. (Her words, not mine.) So… once more into the breach!

Today my goal is to give the lay of the land on the Delta variant and provide some additional words of comfort to parents with kids under 12 years old. 

First, a note on goals

The primary goal of vaccination — the one that is most necessary for us as individuals as well as the public health at large — is to reduce the risk of hospitalization, death, and other serious consequences of COVID-19 infection to such a level that they are as low or lower than any of the risks we willingly took on before COVID-19. 

Please note how I framed that. I’ve noticed that some people look on life pre-COVID as if there were no infectious diseases of note. We have always been at risk for infectious diseases, but the likelihood of those risks were sufficiently low, and the consequences of those threats sufficiently mild, that we lived with them without taking burdensome actions (e.g. wearing a mask, avoiding close contact with people).

So, if we can just get the risk of COVID-19 to approximate those of other pre-COVID risks in terms of likelihood and severity, then we can see friends and family without fear and without masks and without distancing. After all, if COVID-19 just caused a runny nose or a mild cough, then we never would have cared about the virus in the first place.

It also would be nice, but not necessary, to lower our risk of infection (even if it were asymptomatic or just mildly symptomatic with no long-term consequences) to ridiculously low levels so we don’t even think much about getting infected at all.

The Delta variant is not a delta

In the sciences, the Greek letter “delta” is used to signify change. The last time I wrote about variants there was absolutely no evidence that the effectiveness of the mRNA vaccines (Moderna and Pfizer) was impacted by any of the then common variants. My assessment is still the same, even with the Delta variant. In other words, the Delta variant is not a delta. 

I’ll give a little behind the scenes on what has been happening to justify my optimism. First, a caveat: none of the underlying data has been published so I can’t review it in detail. Instead the top-line results have only been summarized in press releases.

Israel announced that they have data showing 64% effectiveness (vs. the original 90% vaccine effectiveness) for the Pfizer vaccine against infection from the Delta variant. This data was reiterated in a Pfizer press release. 

Although I’m sure the report is factually accurate, the underlying data was never described in detail nor was it submitted to the major preprint servers. Later news reports provided additional detail that the data was observational only (no control group) and from a single data source. This makes me very skeptical of the relevance or applicability of the data. 

Even more important, however, is that England’s public health department announced that they have data showing the Pfizer vaccine is 88% effective in preventing symptomatic infection caused by the Delta variant. The England public health data appears to be more robust than that reported by Pfizer.

Also, notice a key difference between the two reports above: all the news stories I could find about the Israeli data stated “infection” and appears to include both asymptomatic and symptomatic infection. If that’s the case, then 64% effectiveness doesn’t bother me at all because I expect somewhat lower vaccine effectiveness if you include asymptomatic infection.

In addition, all of the in vitro data I’ve been able to see shows the mRNA vaccines produce sufficient neutralizing antibodies to the Delta variant, and the quality and quantity of those antibodies is not much different from that seen against the original COVID-19 strain.

But all of that is frankly just noise, because the most important information is that every single piece of data shows high levels of effectiveness (at least 90%) in preventing hospitalizations and deaths from the Delta variant. In addition, 99.9% of all hospitalizations and deaths from COVID-19 in the US are in unvaccinated individuals, which clearly demonstrates the vaccines are remarkably effective.

In short, I maintain that the mRNA vaccines are highly effective against all past and currently circulating variants of COVID-19. I am also optimistic that this will continue to be the case against future variants. The Delta variant is not a concern for vaccinated individuals and should not cause a change in behaviors on the part of vaccinated individuals.

But what about those who can’t get vaccinated, like kids less than 12?

Parents of kids less than 12 years old feel like they are on an island. Those parents are still struggling with fears of what activities to engage in, when to wear masks, and how soon can their “littles” get vaccinated. Many of these items I spoke about in my most recent post. Here are some straight-forward numbers to try and help:

• At the present time the U.S. is averaging 16,000 cases per day, and that number includes all age groups, not just children. Those numbers mean that the daily infection rate for the overall U.S. population is only about 0.04%. So, the true risk of infection to children right now is really low.
• There is a 0.4% risk of hospitalization, a 0.09% risk of MIS-C, and a 0.01% risk of death in children infected with COVID-19. These numbers are large overestimates because the numerator (i.e. the bad things) we have is pretty solid data, but the denominator (all kids with COVID-19) is a large underestimate because testing is less common in kids due to higher rates of asymptomatic or mild infection in kids compared to adults.

Let’s assume that every infection in the first bullet point above is an infection in a kid (absolutely not the case) and that the large overestimates in the second bullet point are accurate. This means that even in the most pessimistic scenario kids only have a:

• 1 in 5,000 chance of being hospitalized from COVID-19
• 1 in 25,000 chance of MIS-C from COVID-19 
• 1 in 250,000 chance of dying from COVID-19

And remember those chances are huge overestimates, and also assume that everyone your children are around is unvaccinated.

But when can my kid get vaccinated?

A loyal reader sent me a link to a news report where the Pfizer CEO anticipated applying for an EUA (Emergency Use Authorization) in September. Typically from the time an application is submitted (as dated by the press release announcing it) there is about four to eight weeks until the vaccine receives an EUA. So figure October/November for when kids ages 2 through 11 can get vaccinated.

There is much more to write about including an update on vaccine safety, duration of immunity and the potential for booster doses. Stay tuned for more.

Stay safe, and go make some lemonade.

If you’re not yet subscribed, please do so. You’ll get all my reviews of the vaccine data straight to your email. Have something to say? Please leave a comment or a question. And don’t forget to forward, share, and keep spreading the word. Thanks for reading.