Delta Variant and Natural Immunity vs. Vaccines

For a little while this summer it was looking as though we might be able to put most of the problems associated with the COVID-19 pandemic behind us. The vaccines were working great and even those who hadn’t been vaccinated were developing good levels of natural immunity following infection (although at a high cost with many suffering long-term injuries along with over 600,000 deaths in this country – and over 4.25 million deaths worldwide). After more than a year of suffering here, and worldwide, it looked as though “herd immunity” might soon be within our reach. Then came the “Delta Variant”, which started taking over as the most prominent variant around the world due to its ability to spread two or three times faster and cause infection much more quickly with an average viral load more than 1000x greater compared to those infected with the original coronavirus strain (Link).  Infection is first detectable in people with the delta variant just four days after exposure, compared with an average of six days among people infected with the original strain of SARS-CoV-2. When the pandemic first began, people spread the original coronavirus to an average of two or three other people while contagious. Today, people infected with the delta variant infect six other people, on average (Link).

“These results suggest that boosting vaccinated individuals with currently available mRNA vaccines would produce a quantitative increase in plasma neutralizing activity but not the qualitative advantage against variants obtained by vaccinating convalescent individuals.”

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More Vaccinated than Unvaccinated people getting infected:

But what about the evidence that even those who are vaccinated still get infected by COVID-19? – particularly the delta variant?  As an example of this, consider a series of large public events that occurred over several days in Cape Cod, Massachusetts (from July 3–17). This “event” or “series of events” if you prefer, resulted in 469 people being infected with Covid-19 (as initially reported by the CDC). Of this number, 346 (74%) occurred in fully vaccinated persons!

That sounds like a problem until one realizes that 72% of the population in Massachusetts has received at least one vaccine dose, and, overall, 4,389,137 people or 63% of Massachusetts’s population has been fully vaccinated. Of those 75 years of age and older, the rate of full vaccination is 81.7% and for those 50-74 years of age, the rate of full vaccination in this state is over 80%. And, the vaccine rate is even high for those who are in their 20s, 30s, and 40s in this region (Link). Only the children have a low rate of vaccination because the vaccines are not available to children yet. And, those attending these large events were supposed to be vaccinated.

Clearly, then, as in the UK, the significant majority of those older than 30 years of age have been fully vaccinated. So, it only stands to reason that the majority of infections, and even deaths, would be among those who have been vaccinated since the effectiveness of the vaccines is not 100%. It’s very good, but not 100%. When it comes to the original type of COVID-19, vaccines not only provide significant protection against hospitalization and death, but also significantly reduce the transmission rate of the virus to others. 

What is different, then, about this Massachusetts data, is that the delta variant seems to have a much higher infection rate, even among those who have been vaccinated, as compared to the original COVID-19 virus of 2020. Just watch Dr. Roger Seheult’s video (linked above), where he explains that the only group of people that has a decreased risk of severe infection requiring hospitalization and/or death from the Delta Variant is not the unvaccinated group, or even the partially vaccinated group, but the fully vaccinated group (within a particular age category).

Again, when it comes to the severity of illness and deaths, all of the data worldwide, the UK data included, strongly supports the conclusion that the unvaccinated, within a particular age category, are at a far far higher risk of hospitalization and death from COVID-19 infections (particularly the delta variant now) as compared to those who are fully vaccinated against COVID-19 – via the mRNA vaccines in particular. More than 99% of those who are dying of COVID-19 right now, within a particular age category, are the unvaccinated – in this country and around the world (Link, Link). 

Many conspiracy theorists (like Dr. Mercola for example) are misinterpreting the data coming from the UK (what’s new). Sure, more vaccinated people are dying in the UK compared to unvaccinated. However, the risk of hospitalization and death is much higher in the unvaccinated. How can that be?

Imagine everyone is now fully vaccinated with COVID vaccines – which are excellent but can’t save all lives. Some people who get infected with COVID will still die. All of these people will be fully vaccinated – 100%. That doesn’t mean vaccines aren’t effective at reducing death.

The risk of dying from COVID doubles roughly every seven years older a patient is. The 35-year difference between a 35-year-old and a 70-year-old means the risk of death between the two patients has doubled five times – equivalently it has increased by a factor of 32. An unvaccinated 70-year-old might be 32 times more likely to die of COVID than an unvaccinated 35-year-old. This dramatic variation of the risk profile with age means that even excellent vaccines don’t reduce the risk of death for older people to below the risk for some younger demographics.

PHE data suggests that being double vaccinated reduces the risk of being hospitalized with the now-dominant delta variant by around 96%. Even conservatively assuming the vaccines are no more effective at preventing death than hospitalization (actually they are likely to be more effective at preventing death) this means the risk of death for double vaccinated people has been cut to less than one-twentieth of the value for unvaccinated people with the same underlying risk profile.

However, the 20-fold decrease in risk afforded by the vaccine isn’t enough to offset the 32-fold increase in the underlying risk of death of a 70-year-old over a 35-year-old. Given the same risk of infection, we would still expect to see more double-vaccinated 70-year-olds die from COVID than unvaccinated 35-year-olds. There are caveats to that simple calculation. The risk of infection is not the same for all age groups. Currently, infections are highest in the youngest and lower in older age groups (Link).