One method of obtaining herd immunity — which is insanely inhumane — would be to let the virus spread and let people get sick, until enough persons have had the disease and recovered to reach herd immunity. Such a program would result in a vast number of entirely unnecessary deaths. So, of course, that approach would be immoral. But there is another way to reach herd immunity, without such a vast cost in suffering and lost human life, and that way is described in this article.
Suppose you have a population in which some persons are immune to a disease, and others are not. Herd immunity occurs when persons who are not immune are nevertheless protected by being surrounded by persons are immune. They are susceptible to being infected with the disease, but those around them are not susceptible, so they cannot pass it on to them. That is herd immunity. Then the Herd Immunity Threshold (HIT) is the percent of the population that must be immune to a disease, either by getting sick and recovering or by being vaccinated, so as to protect the rest of the population. The typical HIT value is 2/3rds (67%). If 2/3rd are immune, the other third are so much less likely to be infected that the disease cannot continue spreading. Many infected persons pass it on to no one, and the epidemic (or pandemic) stops. That is what we want.
But how easily we can accomplish that goal, for any disease, depends upon how infective the disease is, how likely it is to spread from person to person. The R-nought value (R0) is the extent to which a disease is likely to be transmitted. If an average infected person passes the disease on to three other persons, the R0 would be 3.0.
The Herd Immunity Threshold (HIT) is calculated as 1.00 minus 1/R-nought. For measles, a highly infectious disease, the R0 is 18, and so the HIT value would be 1.00 minus 1/18 or 94.44%. That’s the percent of persons who must be immune to reach the Herd Immunity Threshold for measles.
The R0 for Covid-19 is estimated at between 2.2 and 2.7. At 2.7, the HIT is 63.0% — the percent of the population that must be immune to end the spread of the disease. At 2.2, the HIT is 54.5%. Most nations are far from having half their population become infected and recover from Covid-19. So that is not a viable way to stop the pandemic.
Now, if we have a vaccine that is 75% effective, and 75% of the population received the vaccine, then 56.25% of the population would be protected (75% times 75%), and that would be sufficient if the R0 is 2.2 and would not be sufficient if the R0 is 2.7.
For a vaccine that is only 50% effective, vaccinating 75% of the population would be helpful as 37.5% of the population would be protected, but you wouldn’t reach the HIT value that way. The spread of the disease would continue until the percent vaccinated plus the percent who recover and have antibodies in that way equals or exceeds the HIT value.
However, there’s something else we can do: lower the R-nought value. By lowering R0, we lower the HIT value, and that means a lower percentage of persons need to be immune to reach herd immunity. A low enough R0 would mean we could possibly reach HIT without any additional cases or deaths being necessary.
R0 can be lowered in any way that lowers the infectiousness of the disease:
* use of masks
* social distancing
* hand washing
* limiting crowded events
These interventions reduce the infectivity; they reduce the R0 value, bringing down the HIT value. Now we are already doing those things, but we could do better, further reducing infectivity. What else can be done?
One major way to reduce the infectivity of Covid-19 is the use of vitamin D supplements. Vitamin D is proven by over 30 studies to reduce risk of infection, severity, and/or death from Covid-19. The Kaufman study found that just having normal levels of vitamin D in the blood reduces your risk of contracting Covid-19 by over 50% .
Kaufman et al.: “For the entire [study] population those who had a circulating level of 25(OH)D <20 ng/mL had a 54% higher positivity rate compared to those who had a blood level of 30–34 ng/mL." 
What this means is that we can reduce the infectivity of Covid-19 by raising the vitamin D levels of the population, simply by a program of vitamin D “supplementation or sunshine”. If the disease is then 50% less infective, the R0 value approaches 1.35 (half of 2.7) and the HIT value is about 26%. That would mean only 26% of the population needs to be immune from infection and recovery (or a vaccine) to stop the spread of Covid-19, theoretically. So vitamin D can reduce the R0, reducing the HIT and thereby allowing us to reach Herd Immunity with only just over a quarter of the population immune to the disease by vaccination or infection and recovery.
Right now, in the U.S., 8.2 million persons are said to have had the virus; that is the number of “reported cases”. Some estimates put the real number at 10 times that value , which is, at this point in time, 24.8% of the population. By the time a vitamin D Supplementation or Sunshine “SoS” program is completed, we would have exceeded that mark of 26% and would not even need a vaccination program.
Other prophylactic measures should be added to the vitamin D program. There is sufficient evidence from studies that certain vitamins and minerals also reduce risk of infection, severity, or death from Covid-19. These include: vitamin C, selenium, vitamin K, zinc, B1, B2, B12 and perhaps a few others. Some OTC supplements which are not vitamins or minerals might also be helpful, such as quercetin or green tea extract (with EGCG).
Once the HIT is brought down to 1.0 or nearly 1.0 — if indeed we can accomplish that goal — then the pandemic would wind down. The goal is to reduce the infectivity of Covid-19 so that fewer and fewer persons become infected as each day passes, until the infectivity is reduced to near zero.
To obtain a value that low, for such an infectious disease as Covid-19, we need multiple interventions that lower infectivity, including vitamins, minerals, supplements, masks, social distancing, etc. By means of these different interventions that lower the R0 value, lowering the infectivity of the disease, we can reach heard immunity threshold with far fewer deaths and without waiting for a vaccine.
I am not an antivaxxer. I am not against a Covid-19 vaccine. However, we can’t wait until spring of 2021. Too many persons will die between now and then. And if there is a vaccine, it takes months to distribute it, and weeks if not months for each vaccinated person to develop antibodies in reaction to the vaccine. We will need a vaccine, in the end, when all is said and done. But there are immensely helpful steps we can take RIGHT F#$%ing NOW to reduce the infectivity of this disease and protect everyone from suffering and possible death.
So let’s get started.
Ronald L. Conte Jr.
an author, not a doctor
1. Kaufman HW, et al. “SARS-CoV-2 positivity rates associated with circulating 25-hydroxyvitamin D levels.” (2020) PLoS ONE 15(9): e0239252.
2. Havers, Fiona P., et al. “Seroprevalence of antibodies to SARS-CoV-2 in 10 sites in the United States, March 23-May 12, 2020.” JAMA Internal Medicine (2020).