Tag Archives: Aerosols

Vax Results, Biden Boosters, Delta, and the Mask Charade

19 Thursday Aug 2021

Posted by in Coronavirus, Public Health, Uncategorized, Vaccinations

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If this post has an overarching theme, it might be “just relax”! That goes especially for those inclined to prescribe behavioral rules for others. People can assess risks for themselves, though it helps when empirical information is presented without bias. With that brief diatribe, here are a few follow-ups on COVID vaccines, the Delta wave, and the ongoing “mask charade”.

Israeli Vax Protection

Here is Jeffrey Morris’ very good exposition as to why the Israeli reports of COVID vaccine inefficacy are false. First, he shows the kind of raw data we’ve been hearing about for weeks: almost 60% of the country’s severe cases are in vaccinated individuals. This is the origin of the claim that the vaccines don’t work. 

Next, Morris notes that 80% of the Israeli population 12 years and older are vaccinated (predominantly if not exclusively with the Pfizer vaccine). This causes a distortion that can be controlled by normalizing the case counts relative to the total populations of the vaccinated and unvaccinated subgroups. Doing so shows that the unvaccinated are 3.1 times more likely to have contracted a severe case than the vaccinated. Said a different way, this shows that the vaccines are 67.5% effective in preventing severe disease. But that’s not the full story!

Morris goes on to show case rates in different age strata. For those older than 50 (over 90% of whom are vaccinated and who have more co-morbidities), there are 23.6 times more severe cases among the unvaccinated than the vaccinated. That yields an efficacy rate of 85.2%. Vaccine efficacy is even better in the younger age group: 91.8%. 

These statistics pertain to the Delta variant. However, it’s true they are lower than the 95% efficacy rate achieved in the Pfizer trials. Is Pfizer’s efficacy beginning to fade? That’s possible, but this is just one set of results and declining efficacy has not been proven. Israel’s vaccination program got off to a fast start, so the vaccinated population has had more time for efficacy to decay than in most countries. And as I discussed in an earlier post, there are reasons to think that the vaccines are still highly protective after a minimum of seven months.

Biden Boosters

IIn the meantime, the Biden Administration has recommended that booster shots be delivered eight months after original vaccinations. There is empirical evidence that boosters of similar mRNA vaccine (Pfizer and Moderna) might not be a sound approach, both due to side effects and because additional doses might reduce the “breadth” of the antibody response. We’ll soon know whether the first two jabs are effective after eight months, and my bet is that will be the case.

Is Delta Cresting?

Meanwhile, the course of this summer’s Delta wave appears to be turning a corner. The surge in cases has a seasonal component, mimicking the summer 2020 wave as well as the typical Hope-Simpson pattern, in which large viral waves peak in mid-winter but more muted waves occur in low- to mid-latitudes during the summer months.

Therefore, we might expect to see a late-summer decline in new cases. There are now 21 states with COVID estimated reproduction rates less than one (this might change by the time you see the charts at the link). In other words, each new infected person transmits to an average of less than one other person, which shows that case growth may be near or beyond a peak. Another 16 states have reproduction rates approaching or very close to one. This is promising.

Maskholes

Finally, I’m frustrated as a resident of a county where certain government officials are bound and determined to impose a mask mandate, though they have been slowed by a court challenge. The “science” does NOT support such a measure: masks have not been shown to mitigate the spread of the virus, and they cannot stop penetration of aerosols in either direction. This recent article in City Journal by Jeffrey H. Anderson is perhaps the most thorough treatment I’ve seen on the effectiveness of masks. Anderson makes this remark about the scientific case made by mask proponents:

“Mask supporters often claim that we have no choice but to rely on observational studies instead of RCTs [randomized control trials], because RCTs cannot tell us whether masks work or not. But what they really mean is that they don’t like what the RCTs show.”

Oh, how well I remember the “follow-the-science” crowd insisting last year that only RCTs could be trusted when it came to evaluating certain COVID treatments. In any case, the observational studies on masks are quite mixed and by no means offer unequivocal support for masking. 

A further consideration is that masks can act to convert droplets to aerosols, which are highly efficient vehicles of transmission. The mask debate is even more absurd when it comes to school children, who are at almost zero risk of severe COVID infection (also see here), and for whom masks are highly prone to cause developmental complications.

Closing Thoughts

The vaccines are still effective. Data purporting to show otherwise fails to account for the most obvious of confounding influences: vaccination rates and age effects. In fact, the Biden Administration has made a rather arbitrary decision about the durability of vaccine effects by recommending booster shots after eight months. The highly transmissible Delta variant has struck quickly but the wave now shows signs of cresting, though that is no guarantee for the fall and winter season. However, Delta cases have been much less severe on average than earlier variants. Masks did nothing to protect us from those waves, and they won’t protect us now. I, for one, won’t wear one if I can avoid it.

Note: This post also appears at The American Reveille.

Herd Immunity To Public Health Bullshitters and To COVID

16 Monday Aug 2021

Posted by in Coronavirus, Herd Immunity, Uncategorized

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My last post had a simple message about the meaning of immunity: you won’t get very sick or die from an infection to which you are immune, including COVID-19. Like any other airborne virus, that does NOT mean you won’t get it lodged in your eyeballs, sinuses, throat, or lungs. If you do, you are likely to test positive, though your immunity means the “case” is likely to be inconsequential.

As noted in that last post, we’ve seen increasing COVID case counts with the so-called Delta variant, which is more highly transmissible than earlier variants. (This has been abetted by an uncontrolled southern border as well.) However, as we’d expect with a higher level of immunity in the population, the average severity of these cases is low relative to last year’s COVID waves. But then I saw this article in ScienceAlert quoting Sir Andrew Pollard, a scientist affiliated AstraZeneca and the University of Oxford. He says with Delta, herd immunity “is not a possibility” — everyone will get it.

Maybe everyone will, but that doesn’t mean everyone will get sick. His statement raises an obvious question about the meaning of herd immunity. If our working definition of the term is that the virus simply disappears, then Pollard is correct: we know that COVID is endemic. But the only virus that we’ve ever completely eradicated is polio. Would Pollard say we’ve failed to achieve herd immunity against all other viruses? I doubt it. Endemicity and herd immunity are not mutually exclusive. The key to herd immunity is whether a virus does or does not remain a threat to the health of the population generally.

Active COVID infections will be relatively short-lived in individuals with “immunity”. Moreover, viral loads tend to be lower in immune individuals who happen to get infected. Therefore, the “infected immune” have less time and less virus with which to infect others. That creates resistance to further contagion and contributes to what we know as herd immunity. While immune individuals can “catch” the virus, they won’t get sick. Likewise, a large proportion of the herd can be immune and still catch the virus without getting sick. That is herd immunity.

One open and controversial question is whether uninfected individuals will require frequent revaccination to maintain their immunity. A further qualification has to do with asymptomatic breakthrough infections. Those individuals won’t see any reason to quarantine, and they may unwittingly transmit the virus.

I also acknowledge that the concept of herd immunity is often discussed strictly in terms of transmission, or rather its failure. The more contagious a new virus, like the Delta variant, the more difficult it is to achieve herd immunity. Models predicting low herd immunity thresholds due to heterogeneity in the population are predicated on a given level of transmissibility. Those thresholds would be correspondingly higher given greater transmissibility.

A prominent scientist quoted in this article is Paul Hunter of the University of East Anglia. After backing-up Pollard’s dubious take on herd immunity, Hunter drops this bit of real wisdom:

“We need to move away from reporting infections to actually reporting the number of people who are ill. Otherwise we are going to be frightening ourselves with very high numbers that don’t translate into disease burden.”

Here, here! Ultimately, immunity has to do with the ability of our immune systems to fight infections. Vaccinations, acquired immunity from infections, and pre-existing immunity all reduce the severity of later infections. They are associated with reductions in transmission, but those immune responses are more basic to herd immunity than transmissability alone. Herd immunity does not mean that severe cases will never occur. In fact, more muted seasonal waves will come and go, inflicting illness on a limited number of vulnerables, but most people can live their lives normally while viral reproduction is contained. Herd immunity!

Sadly, we’re getting accustomed to hearing misstatements and bad information from public health officials on everything from mask mandates, lockdowns, and school closings to hospital capacity and vaccine hesitancy. Dr. Pollard’s latest musing is not unique in that respect. It’s almost as if these “experts” have become victims of their own flawed risk assessments insofar as their waning appeal to “the herd” is concerned. Professor Hunter’s follow-up is refreshing, however. Public health agencies should quit reporting case counts and instead report only patients who present serious symptoms, COVID ER visits, or hospitalizations.

Note: This post also appears at The American Reveille (or will soon!).

Effective Immunity Means IF YOU CATCH IT, You Won’t Get Sick

12 Thursday Aug 2021

Posted by in Coronavirus, Uncategorized, Vaccinations

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Listen very carefully: immunity does NOT mean you won’t get COVID, though an infection is less likely. Immunity simply means your immune system will be capable of dealing with an infection successfully. This is true whether the immunity is a product of vaccination or a prior infection. Immunity means you are unlikely to have worse than mild symptoms, and you are very unlikely to be hospitalized. (My disclaimer: I am opposed to vaccine mandates, but vaccination is a good idea if you’ve never been infected.)

I emphasize this because the recent growth in case numbers has prompted all sorts of nonsensical reactions. People say, “See? The vaccines don’t work!” That is a brazenly stupid response to the facts. Even more dimwitted are claims that the vaccines are killing everyone! Yes, there are usually side effects, and the jabs carry a risk of serious complications, but it is minuscule.

Vaccine Efficacy

Right out of the gate, we must recognize that our PCR testing protocol is far too sensitive to viral remnants, so the current surge in cases is probably exaggerated by false positives, as was true last year. Second, if a large share of the population is vaccinated, then vaccinated individuals will almost certainly account for a large share of infected individuals even if they have a lower likelihood of being infected. It’s simple math, as this explanation of base rate bias shows. In fact, according to the article at the link:

“… vaccination confers an eightfold reduction in the risk of getting infected in the first place; a 25-fold reduction in risk of getting hospitalized; and a 25-fold reduction in the risk for death.”

The upshot is that if you are vaccinated, or if you have acquired immunity from previous exposure, or if you have pre-existing immunity from contact with an earlier COVID strain, you can still “catch” the virus AND you can still spread it. Both are less likely, and you don’t have as much to worry about for your own health as those having no immunity.

As for overall vaccine efficacy in preventing death, here are numbers from the UK, courtesy of Phil Kerpen:

The vertical axis is a log scale, so each successive gridline is a fatality rate 100x as large as the one below it. Obviously, as the chart title asserts, the “vaccines have made COVID-19 far less lethal.” Also, at the bottom, see the information on fatality among children under age 18: it is almost zero! This reveals the absurdity of claims that children must be masked for schools to reopen! In any case, masks offer little protection to anyone against a virus that spreads via fine aerosols. Nevertheless, many school officials are pushing unnecessary but politically expedient masking policies

Delta

Ah, but we have the so-called Delta variant, which is now dominant and said to be far more transmissible than earlier variants. Yet the Delta variant is not as dangerous as earlier strains, as this UK report demonstrates. Delta had a case fatality rate among unvaccinated individuals that was at least 40% less than the so-called Alpha variant. This is a typical pattern of virus mutation: the virus becomes less dangerous because it wants to survive, and it can only survive in the long run by NOT killing its hosts! The decline in lethality is roughly demonstrated by Kelly Brown with data on in-hospital fatality rates from Toronto, Canada:

The case numbers in the U.S. have been climbing over the past few weeks, but as epidemiologist Larry Brilliant of WHO said recently, Delta spreads so fast it essentially “runs out of candidates.” In other words, the current surge is likely to end quickly. This article in Issues & Insights shows the more benign nature of recent infections. I think a few of their charts contain biases, but the one below on all-cause mortality by age group is convincing:

The next chart from Our World In Data shows the infection fatality rate continuing its decline in the U.S. The great majority of recent infections have been of the Delta variant, which also was much less virulent in the UK than earlier variants.

Furthermore, it turns out that the vaccines are roughly as effective against Delta and other new variants as against earlier strains. And the newest “scary” variants, Kappa and Lambda, do not appear to be making strong inroads in the U.S. 

Fading Efficacy?

There have been questions about whether the effectiveness of the vaccines is waning, which is behind much of the hand-wringing about booster shots. For example, Israeli health officials are insisting that the effectiveness of vaccines is “fading”, though I’ll be surprised if there isn’t some sort of confounding influence on the data they’ve cited, such as age and co-morbidities. 

Here is a new Mayo Clinic study of so-called “breakthrough” cases in the vaccinated population in Minnesota. It essentially shows that the rate of case diagnosis among the vaccinated rose between February and July of this year (first table below, courtesy of Phil Kerpen). However, the vaccines appear only marginally less effective against hospitalization than in March (second table below).

The bulk of the vaccinated population in the U.S. received their jabs three to six months ago, and according to this report, evidence of antibodies remains strong after seven months. In addition, T-cell immunity may continue for years, as it does for those having acquired immunity from an earlier infection. 

Breakthroughs

It’s common to hear misleading reports of high numbers of “breakthrough” cases. Not only will these cases be less menacing, but the reports often exaggerate their prevalence by taking the numbers out of context. Relative to the size of the vaccinated population, breakthrough cases are about where we’d expect based on the original estimates of vaccine efficacy. This report on Massachusetts breakthrough hospitalizations and deaths confirms that the most vulnerable among the vaxed population are the same as those most vulnerable in the unvaxed population: elderly individuals with comorbidities. But even that subset is at lower risk post-vaccination. It just so happens that the elderly are more likely to have been vaccinated in the first place, which implies that the vaccinated should be over-represented in the case population.

Conclusion

The COVID-19 vaccines do what they are supposed to do: reduce the dangers associated with infection. The vaccines remain very effective in reducing the severity of infection. However, they cannot and were not engineered to prevent infection. They also pose risks, but individuals should be able to rationally assess the tradeoffs without coercion. Poor messaging from public health authorities and the crazy distortions promoted in some circles does nothing to promote public health. Furthermore, there is every reason to believe that the current case surge in Delta infections will be short-lived and have less deadly consequences than earlier variants.

Note: This post also appears at The American Reveille.

Blow Me Down: Obesity, Age, and Aerosol-Borne Particles

09 Friday Apr 2021

Posted by in Coronavirus, Lockdowns, Public Health

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Super-spreading events are gatherings at which one or more attendees are already harboring an infection and manage to transmit it to a number of others. These people, in turn, spread it to their close contacts, possibly at the same event. Super-spreading has dominated the transmission of COVID-19. These transmissions have almost always taken place indoors in spaces with limited ventilation, and they have usually involved close or prolonged contact. In addition, super-spreading originates with a small subset of infected individuals. That’s essentially what the chart above shows. It ranks individual subjects by their exhaled quantity of aerosolized particles per liter of air.

For more than a year, we’ve also known that obesity and age are associated with more severe COVID infections. Now, it’s startling to learn that obese and/or older, infected individuals are more prone to transmitting virus: this study found that a high body mass index (BMI) is associated with significantly greater quantities of exhaled aerosol, and that age has a similarly strong association. So called BMI-years, or age x BMI, has an extremely powerful association with the exhalation of aerosol-borne particles. The authors, David A. Edwards, et al, believe this is a consequence of the properties of mucus produced by different individuals in response to infections and how their lungs and airways handle it. The authors say:

“Our findings indicate that the capacity of airway lining mucus to resist breakup on breathing varies significantly between individuals, with a trend to increasing with the advance of COVID-19 infection and body mass index multiplied by age (i.e., BMI-years). Understanding the source and variance of respiratory droplet generation, and controlling it via the stabilization of airway lining mucus surfaces, may lead to effective approaches to reducing COVID-19 infection and transmission. … ”

“Surfactant and mucin compositional and structural changes, driven, in part, by physiological alterations of the human condition—including diet (10), aging (11), and COVID-19 infection itself (12)—may therefore be anticipated to alter droplet generation and droplet size (7) during acts of breathing.”

So there is substantial variation in the exhalation of aerosol-borne particles across individuals. In the study, less than 20% of healthy subjects produced more than 156 particles per liter of air, accounting for 80% of the exhaled particles. This defined their so-called “super-spreader” cohort. The association of BMI-years and exhaled particles was less pronounced but still positive within the “low-spreader” cohort.

Edwards, et al speculate that these fine droplets might help explain the greater severity of COVID infections among the elderly and obese. Not only does the breakup of mucus into tiny droplets cause these individuals to exhale aerosols more profusely, it probably also leads to deep penetration into their lung tissue.

This knowledge might be broadly applicable to infectious diseases, and SARS viruses in particular. The elderly know they are vulnerable. It’s not clear that the obese have viewed themselves as vulnerable, but they should, even in the age of “body positivity“. And not only are they vulnerable: they appear to pose an elevated hazard to others. I came across a couple of sardonic comments that got right to the apparent elephant in the room: “Instead of a mask mandate, how about a push-up mandate?”; and “Instead of a vaccine passport, how about a BMI passport?”

The debate about how to care for the most vulnerable is ongoing, but the mere mention of regularities like those identified by the study might lead to proposals for coercive policies. But first, a few practical points to bear in mind: 1) while the study identifies a major risk factor for transmission, it must be replicated by others, and there must be research into the underlying reasons for the phenomenon; 2) while the obese and seniors may be more likely to super-spread, not all of them are super-spreaders; and 3) as a matter of policy, how would “super-spreaders” be defined? What would be the cutoff BMIs at various ages? No matter what was decided, restrictive policies predicated on mere statistical associations would involve gross injustices to a large number of individuals.

With the degree of acquired immunity already in the population and fairly widespread voluntary vaccination (since alarmists have scared the bejeezus out of everyone), the whole issue might seem moot. It’s not, however, because COVID-19 is likely to become endemic, the immunities of some individuals might erode more quickly than expected, new and more dangerous variants might arise, and new SARS viruses are likely to emerge with time.

In a pandemic, however, and even without knowing who is infected, it is ethically barbaric to probabilistically isolate classes of individuals, whether based on age, BMI, or anything other than contagious status. The social cost is simply unacceptable. Instead, public health authorities should provide information to those at high risk, facilitate vaccination for those who desire it, and promote rapid, at-home tests. This is essentially a deregulatory agenda relative to the mindless lockdown approaches favored by so many public health experts.

Everyone must balance their own personal risks and rewards. Based on the study of exhaled particles discussed above, some might shun the obese and seniors until the threat has passed. Some of the obese and elderly might shun each other. That might be another regrettable dimension of the costs of a pandemic. On the other hand, perhaps more of us will respond to the unquestionably positive incentives for weight loss, of which we’re almost all aware.

Lockdown-Righteous Morons Condemn Beachgoers

19 Sunday Apr 2020

Posted by in Liberty, Pandemic, Public Health

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I’m often inspired by social media because that’s where the sacred cows graze. Today I saw a juicy one… but actually, the linked article was not surprising: the headline claimed that Jacksonville, Florida residents were flocking to local beaches after they’d been reopened. What grabbed me were the half-witted condemnations made by the poster and his friends. One individual, a Jacksonville resident, claimed that the article was incorrect, that this was “not happening in Jax”. But many of the commenters were horrified by the accompanying photo, a view down the beach showing a number of walkers. If you’ve ever been to a beach, you probably know that such a visual perspective can exaggerate crowd conditions. They looked adequately distanced to me, and I’d bet most of the people or small groups in the photo were a good 20+ feet apart.

The comments on the post were a display of unbridled anger: those people on the beach would be sorry when they caused a second spike in coronavirus cases. How monstrous were these Jaxers to chance infecting others! A few expressed hope that the beachgoers would get sick, as if they’d learn their lesson. And in a delicious case of projection by the uninformed, the hashtag #FloridaMorons was trending on social media. These ugly, nitwitted nannies just can’t get over their need to control their fellow man, while lacking the knowledge to do so sensibly.

Not only did the people on the beach look adequately distanced to the rational eye, but unless you’re an unreformed hugger or “close talker”, the chance of contracting coronavirus outdoors is slim to none! That’s especially true on a beach, where there is typically a decent breeze.

A recent study conducted by Chinese researchers on the environments in which clusters of Covid infections were originally contracted showed that outdoor transmission is very unlikely:

“…among our 7,324 identified cases in China with sufficient descriptions, only one outdoor outbreak involving two cases occurred.”

The authors conclude that coronavirus transmission is an indoor phenomenon.

A Q&A from Time includes the question: Is there any difference between being indoors and outdoors when it comes to transmission? Here is part of the response:

“We all occupy an area in three dimensional space, and as we move away from one another, the volume of air space on which we have an impact expands enormously. ‘If you go from a 10-ft. sphere to a 20-ft. sphere you dilute the concentration [of contaminated air] eight-fold,’ says Dr. Christopher Gill, associate professor of global health at Boston University School of Public Health.”

“‘Within seconds [a virus] can be blown away,’ […] Sunlight may also act as a sterilizer, Gill says. Ultraviolet wavelengths can be murder—literally—on bacteria and viruses, though there hasn’t yet been enough research to establish what exactly the impact of sun exposure is on SARS-CoV-2, the virus responsible for COVID-19.”

There is evidence, however, that high temperatures and humidity reduce the spread of the virus (and see here). That sounds like the beach to me! Whether by droplets or aerosols, confined spaces are where transmission happens. It is almost exclusively an indoors phenomenon, aggravated by HVAC air flows that create dry conditions.

Social distancing is still important at the moment, but keeping people indoors is not conducive to public health. Most of the country (well, outside of downstate New York)  is on a path to stanching the contagion. Under these circumstances, you can expect people to push back against unreasonable demands to stay off the beach, stay off an outdoor job, or even stay off their indoor job where there is good ventilation with fresh air, and where distance can be maintained. These little social-media tyrants should pry off their jack-boots and get some sand between their toes!