The latest from my doc on the pandemic, vaccinations, masks, and Delta

August 9, 2021 • 12:30 pm

My extremely competent and science-oriented physician, Dr. Alex Lickerman, has written post #14 in his continuing series about the coronavirus and the pandemic. It’s free, and you can read it by clicking on the screenshot below.

This one answers a number of questions that many of us have. I’ll give a precis of the answers at the end, but you need to read the whole thing. After all, immunized or not, it’s your health. I think you’ll find the answers reassuring.  And what I like about this post, as with the others, is that the answers are completely driven by data.  When the data are ambiguous or unclear, Alex lets us know.

Alex has volunteered to answer readers’ questions, so feel free to ask them in the comments section below.

Some of the questions asked and answered (or not answered if we don’t have data):

  • Is the Delta variant of cornavirus more contagious than other strains of the virus.
  • Does the Delta variant cause more severe disease than the other variants?
  • How effective are the vaccines against the Delta variant?
  • How much do we need to worry about “breakthrough infections?  Here I’ll quote something Alex notes:

But here’s the bottom line: the absolute risk of becoming infected to which vaccinated people are being exposed in most situations in which they find themselves will be far less than 7.2 to 28.8 percent.

This does explain, however, why breakthrough infections with Delta can and do occur. But what we care about most—and what the vaccines were really designed to mitigate—isn’t the risk of catching COVID-19. It’s the risk of being hospitalized and dying from it (as well as the risk of developing long-COVID). Here, the CDC data tells the real story: as of this writing (at a time when, as mentioned above, the Delta variant is the dominant strain infecting people in the U.S.), of 164 million people fully vaccinated (with a mix of the mRNA vaccines and the J&J vaccine), 5,285 people have been hospitalized for COVID-19 (which yields a risk of being hospitalized from severe COVID-19 if you’re immunized of 0.003 percent), and of those 1,191 died (which yields a risk of dying from COVID-19 if you’re immunized of 0.0007 percent). When you consider the risks most of us take every day without worrying about them at all—for example, over the course of a year, the odds of getting into a car accident are 3.7 percent on average and the odds of dying in a car accident are 0.3 percent, making the annual risk of dying from a car accident 0.01 percent, which is 14 times the risk of an immunized person dying from COVID-19—our inability to think statistically clearly has us afraid of the wrong things. (This goes for the decision to be vaccinated as well: our annual risk of dying from a car accident turns out also to be 14 times the risk of the most common serious adverse reaction to the vaccines—blood clots with the J&J vaccines—which occurs at the same rate as the rate of death from COVID-19 if you’re fully immunized, a rate of 0.0007 percent.)

  • Does immunity conferred by the vaccines wane over time? If so, at what rate?
  • Should we be looking to get “booster” (third) vaccinations?
  • Can fully vaccinated people spread the variant? If so, should vaccinated people mask up?
  • Is traveling safe now?

And I’ll give you a peek at the answers but, as I said, read the whole piece and then fire away with questions. A quote from the article:

CONCLUSION: It’s hard to know how to think about immunization, the Delta variant, and how we should behave in different circumstances to keep ourselves and those around us safe. We’re all seeing the science unfold in real time, revealing just how messy, uncertain, and difficult it is to figure out what’s really true. But, though it takes time, science ultimately gives us answers we can rely on. We can all argue about what policies make the most sense based on what the science shows, but it’s the science we should all use to help us guide our own behavior. And, as of this writing, the science says the following:

  1. The Delta variant is more contagious than other variants.

  2. The Delta variant may be more dangerous than other variants.

  3. The vaccines are likely somewhat less effective in preventing infection with the Delta variant, but still offer an enormous amount of protection. Breakthrough infections are occurring, but they are overwhelmingly mild.

  4. Vaccinated people probably can transmit the infection but almost certainly at a lower rate than unvaccinated people.

  5. The vaccines remain unbelievably effective at preventing hospitalization and death from the Delta variant, so much so that vaccinated people can continue to live as they did before the onset of the pandemic, with the possible exception of wearing masks to prevent asymptomatic spread to vulnerable people in areas of high prevalence of disease.

  6. A third booster shot for non-immunocompromised people doesn’t make sense at this point in the pandemic. Some people who are immunocompromised may want to consider a third shot.

48 thoughts on “The latest from my doc on the pandemic, vaccinations, masks, and Delta

  1. Thanks, Prof and Doc. Three questions: 1) What reasons do we have to think that the Delta variant is more dangerous (more severe or deadlier) than the vanilla Covid-19; 2) Do we know what the mortality rate is for non-vaccinated people; 3) I keep hearing that there isn’t actually a test for the Delta variant. Is that so, and, if so, how can we tell which variant a person has?

    1. 1) the best data showing there’s likely an increased risk of hospitalization (a good surrogate for more severe infection) of Delta is from the Scotland study that I referenced in the blog post. Two other studies I didn’t reference had Delta looking even worse, but I thought there were serious methodological problems with those papers so didn’t reference them.

      2) I’m having a hard time finding exact data on mortality rate for unvaccinated people for some reason, but it’s probably around 1.7% (given that almost all deaths have been in unvaccinated people and that’s the case-fatality ratio from the Hopkins tracker).

      3) Some labs are able to sequence the variants that people turn positive for, but since Delta now accounts for almost 94% of all COVID-19 infections in the U.S., if you get COVID, it’s almost certainly Delta.

  2. My elderly wife was fully vaccinated, followed current protocols and still got a breakthrough infection (probably on a visit to Chicago) and needed anti-body treatments (BAM) to recover, which she did at home. She also had some comorbidities…my guess is that, sans vaccine, I would have gotten a call from the hospital instead.

    I strongly urge older people to mask up when indoors around strangers.

    1. As for question 2, as yet there is no indication that the delta variant has a higher mortality rate, just a higher infection rate. What we do see is that it might be more harmful to younger age groups. There are indications, but has not been firmly established (yet?).

  3. “…the risk of being hospitalized and dying from it ”

    While the vaccine is vitally important, it is not the key factor in determining hospitalization and death.

    The key factor is obesity.

    1. Yes and no, vaccinated obese have a lower hospitalisation and death rate than unvaccinated obese. But indeed the obese are at a higher risk of serious disease an death.

    2. Your point is unclear, at best. It sounds like an excuse to not be vaccinated. (“I’m thin, I don’t need it!”)

      The key factor is exposure to SARS-CoV-2. Vaccination greatly reduces the chance of this exposure making you seriously ill. Or dead. Comorbidity factors can’t be changed, for the most part. Vaccination status is easily changed.

      1. “excuse to not be vaccinated” is rejected. Starting with myself, I am. referring to my phrase “While the vaccine is vitally important, ”

        So, rejected.

        Meanwhile, it is completely clear that obesity is the key determinate of the risk of being hospitalized and dying from it, having contracted COVID.

        1. I didn’t mean that you were making an excuse for yourself. You may be old and fat, as well as vaccinated, for all I know. But you do seem to be making an excuse for those who are not obese to not bother with the jabs. If an obese person is fully vaccinated they are unlikely to die in a hospital, assuming they are exposed.

          There are plenty of young and fit people filling the beds in hospitals right now. And plenty of obese but vaccinated people who are not filling those beds. The pandemic continues because of unvaccinated people, not because of fat people.

          Vaccination is our only way out of this pandemic. Your point remains unclear. At best.

          1. Absolutely…one of my friends has completed several 100 mile footraces, many (most) well under 24 hours. He got it last fall and was in the hospital for about a month; in the ICU for at least a week. He is getting stronger now..but COVID came close to killing him and there are GOFUNDME for his medical/loss of work expenses.

        2. It is not clear what you mean for the first part, regarding vaccine status. But just in case (and sorry if I misinterpret) but: EVERYONE who is not vaccinated is at enhanced risk of hospitalization and dying of Covid, and these risks are far, far higher than the risk of adverse reactions to the vaccines. There is zero excuse to not be vaccinated unless you have underlying conditions against vaccines in general.
          Further, an infected person is at very high risk of passing on the virus to others, and the game of Russian roulette is played over again and again against those unwitting persons, and then the people they infect, and so on. So there is the immorality of it all.

          I don’t understand why people think its the best thing for them to not be vaccinated.

  4. Just a note from the news today. All military will have the vaccine by September. I believe the vaccination rate in the military is already at 60% without this mandatory announcement.

        1. Yes, I was just remembering the overall. Vermont would be the opposite, the last time I looked. I wonder whether the state numbers include those military personnel who happen to be stationed there.

  5. I think the risk-calculation of being hospitalized and dying from COVID-19 is not correctly done.
    It is true that 5286 people hospitalized of 164 million people fully vaccinated would
    equal 0,003%. The problem is, that not all vaccinated people got sufficiently exposed to the virus in a way normally leading to infection (this number, as well as the number of hospitalizations will still grow).

    Nevertheless the comparison of numbers of COVID related deaths (vaccinated vs. not vaccinated) speak for themselves: “On July 16, 2021, Centers for Disease Control and Prevention Director Dr. Rochelle Walensky revealed that 99.5% of recent U.S. deaths from COVID-19 were of unvaccinated people.”

    When adjusting for the higher percentage of people actually being vaccinated the comparison looks even more clear…

    1. Well, I think the effective risk is as calculated. You have a sample size of 9-figures in many different environments and age groups, etc. This is, in fact, the practical risk: What you can expect in the real world.

      1. In the real world you can still expect to catch the bug.
        My beef is that 5286 is the present number of people hospitalized. This number will rise.

        If the number of hospitalized people rises the risk would rise according to that calculation. That makes no sense. The risk should be the expected probability of hospitalization not the percentage of vaccinated people so far being hospitalized.
        Am I missing something?

  6. Hi Alex,
    Many people are on immuno-suppressant drugs and so are considered to be at greater risk of covid. Less active immune system = harder to fight off a virus. However, it also seems to be the case that serious illness from covid is often an immune-system over-reaction. Thus one might hypothesize that someone on a drug such as adalimumab would have a lower chance of serious illness. After all, the whole point of adalimumab is to reduce an auto-immune condition by stopping the immune system over-reacting.

    So, is there any actual evidence or studies of how people on immuno-suppressant drugs actually fair if they catch covid?

    1. Super small study in kidney transplant recipients: Larger study of patients with CLL: In both, risk of severe illness was greater. We know from studies of prednisone in hospitalized patients with low oxygen levels that the timing and level of illness impact the effects of modulating the immune system down. Patients given steroids who weren’t hypoxic (low blood level oxygen) actually did slightly worse than those not given steroids, but patients here were hypoxic and given steroids did better than those not given steroids.

  7. I guess the question I have is-
    What are the risks for otherwise healthy people, vaccinated or not?

    A couple of evenings ago, we were watching the news, and they presented a story about a young person who unexpectedly caught Covid and passed away. I don’t want to minimize the pain of the family, but when they showed an image of the person, they were clearly morbidly obese. This was not the first time such a story was shown.

    As best I can tell, the statistics usually given for hospitalization and death don’t seem to differentiate between previously healthy people, and those with serious comorbidities. That being the case, it is difficult for a healthy person to assess what risks they face from the disease. Previous pandemics, like the Spanish flu, seem to have posed extreme risks even to young, healthy, well nourished people.

    I do wonder if any effort has been made to determine what part of the 1.7% of confirmed case fatalities were otherwise healthy people. The NCHS data indicates that about 8% of Americans are morbidly obese, and around 7% have chronic respiratory diseases. A smaller percentage have CF or other autoimmune disorders. People with those issues are much more likely to have serious adverse effects from many diseases, and it would be good to know how much those folks skew the data.

    1. A few comments:

      1) Everyone’s mileage is going to vary. Some people will be unusually susceptible or resistant to any given infectious agent.

      2) People with any kind of co-morbidities (obesity, heart conditions, compromised immune system, asthma, other pulmonary conditions, etc.) will be the majority of those hospitalized and those who die. (But, keep (1) in mind.)

      3) Age is the strongest predictor of severe/fatal cases. Age is also strongly correlated to (2). The older you get, the worse your comorbidities get.

    2. There are also clearly factors we haven’t yet identified that put people at risk for bad outcomes from COVID. There are healthy young people dying from this disease (in small numbers), and we don’t yet know why.

  8. My experience, having had Covid, is the illness can vary a lot from person to person regardless of your condition. Myself and my wife got it at the same time. We were both sick for weeks, nearly the whole month of January for me. But I got much worse than my wife. We are both over 70 but she is older than me. She never had to go to the hospital but I did three days/two nights in the hospital. I did not need oxygen or any of that. My breathing was okay. But I had become so dehydrated it was dangerous. So getting lots of fluid into me was most of what they did. The cost for two nights was over $11,000 and i live in a cheaper state – Kansas.

    1. Anecdotes are so powerful. We know a family down the street. Early middle age, somewhere. The husband is morbidly obese. He caught Covid and barely got sick. She on the other hand also got Covid and came very close to being hospitalized. Actually, she should have gone. And yet she is one of the most physically fit persons I know. It wears me out hearing how she works on her feet all day (cleaning houses), then goes to the gym or goes on a 5 mile run.
      All the opinions up there about body fat or age being the factor to decide about being vaccinated or not makes no sense to me. This thing can kill anybody. And catching it means you’ll probably spread it to others.
      I don’t understand the Libertarian mind.

  9. Any thoughts on adding an mRNA shot in a patient who has already received a J&J vaccination? Anecdotally I’m hearing about people doing this. While I’m unaware of formal safety testing of this combination mixing AZ with an mRNA seems to be effective. (The specific example I’m thinking of is living and working in a high risk south asian country with marginal healthcare resources but will soon be returning to the US on leave)

    1. I haven’t seen a published study that’s looked at this. Remember though, even though AZ didn’t reduce the risk of infection as much as the mRNA vaccines, it still performed quite well (all risk reductions are relative risk reductions, and because the base rate risks of infection, hospitalization, and death from COVID are relatively low to begin with, AZ reduces the absolute risk of those things quite well).

  10. Thanks for the post PCC(E) and thanks, Dr. Lickerman, for this update and sharing your time.

    Both my parents (mid-70’s) contracted Covid at the end of last year. Both got pretty sick, but neither were hospitalized. But now they refuse to get vaccinated because they think they are immune (I don’t know if they also adhere to conspiracy theories). They only watch FOX, so I don’t think they know much about the Delta variant. What would be your advice to people with this type of attitude? They also travel a lot, don’t wear masks and I’ll be with them for a dinner in a week or so. I’m fully vaccinated, but I worry I can give them the virus.

    1. Oh, that’s too bad. My wife and I had the virus in January, before the vaccine was available but we both got vaccinated in late March and early April. Having had it will not last that long. If they had it last December it is likely their immunity time is over.

    2. You can be tested before you visit.
      They have some immunity, but I’m pretty sure its measurably less than the immunity of someone who is vaccinated. So They are less likely to catch Covid with the vaccine. Also, if they get a break-through infection, although their experience may be a re-run, or even mild (or not!), they will likely pass it on to others who are not vaccinated. So not being vaccinated is immoral by any measure.
      You would want to rehearse how to approach them on getting vaccinated. I just googled “how to talk to someone who won’t get the Covid vaccine” and got lots of hits. I’d start there.

    3. The actual risk of re-infection from people infected naturally is quite low. We don’t know about duration of immunity in the naturally infected vs. immunized yet. There is some data, though, that a single shot after natural infection might improve immunity. I don’t think it’s entirely unreasonable for people who were infected to forego vaccination, but as we’re learning more about the beneficial effects of vaccination, getting at least one shot after natural infection will probably turn out to be wise. More data needed. Your risk of giving your parents the virus is very, very low.

      1. I am one of the people who contracted SARS in 2003 (in Singapore), and it was an experience I do not wish to repeat.
        When Covid came around, my wife caught it from one or more of her patients, and she had more or less severe flu symptoms. I had very mild symptoms, which I might otherwise have confused with a mild cold, except for the loss of taste and smell for a bit.
        We got vaccinated as soon as we could, and she has been re-exposed several times with no ill effects.
        Neither of us are particularly concerned about re-infection at this point, but incidents of some immunized people being infected are in the news these days. It would be more comforting to have some reliable data to base my confidence, but I guess some uncertainty is unavoidable during an apocalypse.

    4. Thanks all for the wise words. I can’t thank you all enough. I have a feeling we’re all going to get this damn thing, regardless our best efforts, sooner or later, just like any prevalent airborne, mutating virus. I also think more of us have had it already and we just don’t know. Covid is maddening, that’s for sure.

  11. I teach at a public university in a red state, with less than 40% full vax rate and very little mask wearing. And a governor and legislator opposed to any mandates (they fired the state health director for promoting vaccines to kids, which will give you a clue to the state). Cases and hospitalizations are soaring in the area.

    School starts in three weeks. The university had been planning on fully returning to pre-pandemic operations, with no vax or mask or distancing requirements among students or staff. Today they finally relented and will require masks.

    Even so, teachers will be in packed classrooms for three hours a week for each course, which would total about 9-12 hours a week with the only protection being masks. It’s a safe bet that less than half the students will be fully vaccinated.

    I’m sure that there are too many variables to make a reliable risk assessment, but does this sound overly risky?

    1. That does sound risk to me, frankly. If everyone in the classroom wears their masks and no one comes to class who’s sick, the risk is fairly low (though with Delta, higher than with other variants). But far less risky would be for everyone in the classroom to be vaccinated (I understand that’s not what’s going to happen).

  12. Great article!

    I had the AZ shot first, and then Pfizer for second dose, over 11 weeks later. My question concerns mixing vaccines:

    What confidence level can we have from the data so far, for the efficacy of mixing vaccines?

    There’s promising data, but what more is required for experts to start to sign off on the proposition that mixing any particular vaccines is safe/and in some ballpark of efficacy? And when will that evidence ever arrive?

    I know the UK seemed to be doing one of the more extensive studies on vaccine mixing, but the results still seem to be only dribbling in, for instance some good looking data from mixing AZ and Pfizer at a 4 week spread, but we are still waiting for data on longer intervals, e.g. 8 – 12 weeks, which was quite common.


    1. We’ll only know the results of these vaccine mixing studies after enough time has passed and the rates of infection in this cohort can be compared to other cohorts (e.g., vaccinated with same vaccine only, not vaccinated, etc.). Takes time. Frustrating, I know.

  13. I constantly hear how “understanding” we should be towards anti-vaxers. Should we be so understanding to people who smoke in restaurants, drive with no brakes or let loose a shotgun down main street b/c they like the sounds of the explosions?

    As a NYer and as somebody who LIVES IN A SOCIETY, and somebody who has studied medicine (drop out, admittedly)…. I’m all out of “understanding” for these people. I read a study the other day connecting IQ with vaccine hesitancy, negatively. Don’t cough your stupid on ME!

    Libertarians should move to the country of their dreams: governmentless, gun-stacked Somalia. Their ideology seems to work well there.


    1. Most of us who got vaccinated are losing patience, clearly.

      The thing is I tried to hold on to empathy for quite a while. But I have interacted with too many vaccine-resistant on many of my hobbyist forums, and also with the very few I know in my own life.

      And unfortunately one thing seems to tie them all together: An inability to think of the risks beyond what it means to them. That is a total failure for any appeal to how their decision affects others, of any appeal to civic duty or the common good. None of it lands, it’s like I’ve started speaking Greek.

      And inevitably they will put forth some level of ignorance and misinformation they’ve imbibed.

      The thing is we are of course all biased in how we sift through information, to one degree or another.
      But even THAT would seem to be at least somewhat telling of a person’s character, or at least their general attitude. The many of us who found our way to being vaccinated no doubt had some bias leading us along through the data, and the stories, and the experts we found compelling in the case for getting vaccinated, including how we all need to work together.

      But at least that seems to a bias towards wanting to be or seem responsible, to wanting to listen to the science, to some aptitude toward the common good when it counts.

      The vaccine resistant are often “excused” by having been “mislead”, maybe having gone down some rabbit hole of misinformation. But the biases operating in their brain that grease that slide in to the stories that will tell them they don’t have to make a choice to help others, that bias to seize upon excuse-giving misinformation like “Covid isn’t so bad as they are telling us, and it’s your body your choice, so you are right that you don’t need to get vaccinated”….that in itself seems to tell us something about the basic character of that person’s thinking. Not always. But…often it seems.

      So when I have hoped that direct interaction with the concerns of the vaccine resistant would breed empathy, unfortunately for me it has generally been the opposite, where some of concerns were confirmed.

  14. good grief all the wonderful posts on wordpress and yet covid is the one people seem to want to read.. personally, there is only one virus and that one is fear and fear alone. the rest is just hype and scams…

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