COVID-19: The WTF Edition

I feel a bit like Michael Corleone in Godfather Part 3 (yes, it’s the worst of the three, but it’s good for this line): Just when I thought I was out they pull me back in!

Unfortunately the only messages about masks, vaccines, and COVID-19 that we’re hearing are: 

Just when you thought it was safe to go back in the water.

And my favorite (this is a family blog so I can’t use profanity):

Well that’s great. That’s just f***ing great man. Now what the f*** are we supposed to do! That’s some real pretty s*** man. Game over man, game over!

To which I say, everyone breathe in, breathe out; breathe in, breathe out; do the hokey pokey, that’s what it’s all about.

Ok, dad humor is done. Let’s do this thing!

Recently I heard from many friends and colleagues a level of anxiety and fear they haven’t felt for quite awhile. My goal today is to present the data, give context, and hopefully allay your fears that things — at least for those of us who are fully vaccinated — are not all that different than they were a month ago.

I was wrong… and right

I’ve tried to be as candid as possible in these blog posts. So I’ll own up right now. 

I was wrong. 

Not about the effectiveness of the vaccines (they are STILL very effective), not about the safety of the vaccines (the mRNA vaccines in particular are very safe), not about them being our ticket out of this mess (oh, they are), but about this… I really thought we’d see a continued low number of COVID cases throughout the summer.

Why was I wrong? Because I was right in this post – life finds a way, especially when it has a high – way to drive on (see the pun I did there? I have a gift). And that highway is large swaths of unvaccinated people.

We only have 49% of our population fully vaccinated, and about 57% of those eligible (those 12 years of age and older). By any historic comparison this is, well, historic. Unfortunately viruses don’t care about historical comparisons. No, the only thing that matters is the frequency of touchpoints between people, primarily unvaccinated people.

What has changed?

After sifting through way too many news reports and CDC “statements,” here are the two things that appear to be different. And yes, these changes appear to be due to the Delta variant. So, in this case, Delta is a delta.

1. The Delta variant appears to be more contagious for the unvaccinated than the previous COVID-19 strains. I say “appears” because I have not been able to review the data, nor can I find the data on the CDC site. All I have is news reports including one of an internal CDC document. I just wish I could actually find the data to evaluate for myself.  (Note the italicized “for the unvaccinated.” Contagiousness is not a relevant characteristic if you are unlikely to get infected or sick in the first place. For example, measles is a horrendously contagious virus, but that isn’t relevant to me because the likelihood of me getting measles is very low.)
2. The CDC also states that if vaccinated individuals get infected with the Delta variant they can harbor sufficiently high concentrations of virus in their respiratory tract to transmit the virus to others. 

What hasn’t changed?

Actually, quite a lot.

I stand by my most recent blog post. The COVID-19 vaccines, especially the mRNA vaccines, are highly effective and retain their effectiveness even against the Delta variant. 

The immunologic data clearly show the vaccines (especially the mRNA vaccines) produce ample concentrations of neutralizing antibodies to provide protection against the Delta variant (and all other variants as well) of COVID-19. 

Perhaps you’ve read about data from Israel documenting effectiveness of only approximately 30-60% of the Pfizer vaccine against the Delta variant? Unfortunately what was not reported in the American media, but made its rounds in the Israeli media, was that these results were widely disputed inside and outside of Israel as not being relevant due to methodological flaws and very small sample sizes. Besides, all this data were in press releases, and were never even submitted to preprint servers for the world to parse. I can’t take a press release seriously if the agency never puts the data out there for the world to see. I simply can’t put this data on the same level as the more comprehensive data I’m about to share.

I will summarize the best effectiveness data below in order to help allay your fears. I will go from low numbers to high numbers.

Three real-world studies showed a vaccine effectiveness anywhere from 72-79% against all confirmed infections (meaning both symptomatic and asymptomatic) caused by the Delta variant. It is normal and expected for effectiveness against all infections, including those without symptoms, to be somewhat less than that seen in the clinical trials which only measured symptomatic infection. Besides, 72-79% is really freaking good! You reduce your risk of infection (including asymptomatic) by three fourths! (Sign me up every day of the week and twice on Sunday!) And this is specifically against the Delta variant.

We have two real-world effectiveness studies that show the mRNA vaccines are 87% and 88% effective against symptomatic infection caused by the Delta variant. These numbers are slightly lower than what the clinical trials showed but that difference is minor and in no way a material difference. (Said in a sarcastic tone of hysteria, “Wait, the vaccine is only 87% instead of 93% effective against symptomatic infection! Nooooooooo! Stock up on toilet paper!”)

And now the big numbers, the ones that are the most important:

We have two real-world effectiveness studies that show vaccine effectiveness of 93-100% against hospitalization caused by the Delta variant. Mic… drop.

What was the change in CDC mask recommendations?

The CDC “guidance” states that vaccinated individuals who live in areas with high infection rates (which are those areas with lower vaccination rates) should wear a mask in indoor settings.

What caused the change in CDC mask recommendations?

The change in the CDC’s mask recommendations are based on one report of a COVID-19 outbreak in Provincetown, Mass. This town hosted multiple events with large public gatherings that attracted thousands of out-of-town visitors. Individuals reported attending densely crowded indoor spaces including bars, restaurants, guest houses, and rental homes. 

The report describes a population whose demographics and underlying disease states may not reflect the population at large. For example, preliminary analyses indicated that 6% of the known cases were in patients infected with HIV, a percentage far higher than the general population. HIV could impact vaccine effectiveness as well as dynamics of viral replication. In other words, I am skeptical that the viral dynamics and transmission patterns of this particular outbreak are reflective of the population at large.

The key piece of data that the CDC drew from this outbreak was that the concentration of virus  in vaccinated but infected individuals was similar to that in infections of unvaccinated persons; 90% of the infections in the outbreak were caused by the Delta variant. But… (and, yes, I do mean that “but”) these results were only from a portion of the vaccinated individuals who became infected, and the report does not describe whether the disease characteristics of that portion of patients match the unvaccinated patients they were compared against. We need more robust data that tells us what the breakdown of asymptomatic, mild, and serious disease was among the entire population and whether the concentrations of virus in each of those subgroups differed. But we won’t get such data because outbreak reports inevitably find many more patients who are sick, especially those with severe disease, because those are the easiest to identify. 

All available evidence shows that vaccinated individuals are more likely to have asymptomatic or mild COVID-19 symptoms. And we know that patients with asymptomatic and mild symptoms usually have lower viral concentrations, which should mean less contagiousness. This outbreak, as currently reported, doesn’t change that! 

An outbreak report is important but it is observational only. I am skeptical that we can extrapolate the findings of this report to the broader population because of fundamental differences in the infection dynamics and immunology of the patients in this outbreak and the need for more detailed data. 

What does the outbreak say about vaccinations?

The headline that the media leads with is that 74% (346 out of the 469) of the known cases in this outbreak occurred in fully vaccinated individuals, and that 90% of all cases were with the Delta variant. While those numbers are true, they imply a fundamentally false and dangerous message.

First, outbreaks are bound to occur even with vaccinated individuals. For example, you hear about outbreaks of measles at Disneyland that occur in vaccinated patients. This does NOT mean that measles vaccines are ineffective.

Second, as the proportion of vaccinated individuals increases, it is simple mathematics that the proportion of vaccinated individuals represented in outbreaks will also increase. Again, this does NOT mean vaccines are ineffective. It simply means they are not 100% effective. I live in the real world, I accept real-world restraints. (Do you not drive any car because you’re only willing to drive a Porsche?)

Third, outbreak reports don’t tell you the total number of people who visited the town, the total number of people exposed who were vaccinated vs. unvaccinated, and the percentage of those exposed who ended up being infected. Mathematically you can easily create a scenario where the Provincetown outbreak fits with the vaccine effectiveness data I describe above.

So what does the outbreak say about vaccinations? Nearly nothing. If anything, based on how quickly the outbreak receded, and that it did not spread throughout the surrounding areas (which has a 69% vaccination rate), this outbreak shows that the COVID-19 vaccines, especially the mRNA vaccines, are highly effective and that high vaccination rates are the key to preventing widespread transmission.

Why the change in mask recommendations?

The change in mask recommendations for vaccinated people is NOT because vaccines are ineffective (they are effective). It is NOT because vaccinated individuals are likely to get infected (they aren’t likely to get infected). It is NOT because the CDC is worried about vaccinated individuals getting sick or dying. It IS because there may be a higher likelihood of transmission if vaccinated individuals get infected with the Delta variant, compared to previous COVID-19 strains.  

To summarize a slightly different way: it is possible that vaccinated persons will be infected, and it is possible that such infected persons will transmit the virus. However, we should be far more concerned with what is likely, not what is possible. 

What is likely is that vaccinated persons don’t get infected, and that if they do get infected they are far more likely to have asymptomatic or mild disease than unvaccinated persons, and therefore less likely to transmit the virus to others.

Even the CDC director, who is way too alarmist for my taste, states that this is still largely a pandemic of the unvaccinated. “The vast majority of transmission, the vast majority of severe disease, hospitalization and death is almost exclusively happening among unvaccinated people.” 

She’s right and the media should be focusing on that.

So we don’t need to wear masks?

I have no doubt that full masking would lower disease transmission for everyone. However, since transmission is “almost entirely” (CDC’s words, not mine) within the unvaccinated, the benefit of masking the fully vaccinated is small. The greatest benefit in mask-wearing is when masks are worn by the unvaccinated. 

The message you heard (regardless of the CDC’s intentions) is that vaccines are ineffective and that they do not change one of the most visual incentives of getting vaccinated. Simply put, the CDC sent out the wrong message.

When you’re communicating with the public you must understand the public’s incentives, not your incentives. You have to understand, without judgement, the culture and concerns that inform their choices. 

I’m not going to write a screed on CDC communications and the groupthink of public health philosophy. I’m simply going to say that the CDC in their tone, and in what they choose to emphasize, and the media in their amplification, has done more harm to vaccine confidence than any Facebook troll.

What will I do? I will wear my mask when asked or required to do so or when I am in a densely crowded environment where the risk of transmission could be high.

A closing note of optimism

I remain optimistic. The vaccines, especially the mRNA vaccines, are highly effective and safe. They significantly reduce an individual’s risk of infection, and bring the risk of hospitalization and death to a point lower than many other risks in our life. 

Stay safe, and go make some lemonade.

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