A Coronavirus Conundrum: Is Vitamin D the Reason for Finland's Unusual Covid Epidemiology?
By An Anonymous Guest Writer
Look at this chart, and ask yourself why the Covid19 death rate in Finland is so much lower than the United Kingdom and the USA. Why are the wintertime peaks and the “Delta” variant uptick so much lower? Actually, the answer is simple. People in Finland have a higher level of immunity to Covid19. But that begs the question “why is the level of immunity so much higher in Finland?”
There are two kinds of immunity – acquired and innate. Acquired immunity is what catching a disease or getting a vaccine produces – antibodies and other defenses keyed to a specific pathogen. In contrast, innate immunity works all the time without the need for the body to develop pathogen-specific defenses. However, innate immunity depends on a key nutrient – Vitamin D3 - to work properly. Nearly all the Vitamin D3 used by the body is produced in the skin by the action of ultraviolet B in sunlight. The more sun you get, the more Vitamin D3 is produced in the skin, and the more robust your innate immunity. There are very few natural dietary sources of Vitamin D3 (fatty fish) and adults don’t get enough from fortified foods (milk) or by taking multivitamin supplements.
Two key papers about another viral disease – influenza - by Dr. John Cannell and his colleagues argue that the incidence and severity of influenza are regulated by innate immunity. This article by Cannell – The Epidemiology of Influenza -https://virologyj.biomedcentral.com/articles/10.1186/1743-422X-5-29 - discusses in detail the relationship between sun exposure, Vitamin D3, innate immunity and the incidence and severity of influenza, and provides a medical paradigm to understand the incidence and severity of Covid-19. Cannell’s other key paper on influenza is Epidemic Influenza and Vitamin D https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2870528/ Both papers are well worth reading.
In the early months of the pandemic there was, understandably, no research showing a relationship between Covid-19 and Vitamin D, but there were intriguing inverse correlations between Covid19 death rates and sun exposure. The website Worldometers.info was providing data on the pandemic all over the world. By the end of August 2020 it was obvious that the pandemic was worse in the northern latitudes, where the virus had arrived in the middle of the winter, than in the southern hemisphere, where it came on shore in the summer. Compare, for example, Great Britain and Australia (worldometers.info):
The seasonality of the pandemic is pronounced. The coronavirus showed up almost simultaneously in the two countries, but its severity is related to wintertime, when the sun is lower in the sky and cold weather keeps people indoors or heavily clothed when they go outside, reducing their sun exposure.
By summer 2020 some scientific studies of Covid and Vitamin D began to appear. The website Grassroots Health publishes summaries of key papers with useful graphs. https://www.grassrootshealth.net/blog/review-vitamin-d-immune-health/
One early observational study used data from Quest Diagnostics, a commercial medical laboratory service that tests samples for millions of patients. Researchers found 190,000 patients who had a Vitamin D test in 2019 and a Covid test in 2020. People with the highest Vitamin D levels had the lowest rates of Covid positivity. https://www.grassrootshealth.net/blog/new-study-shows-53-lower-covid-19-positivity-rate-among-higher-vitamin-d-levels/
Another early study showed that administration of sufficient Vitamin D when patients were admitted to the hospital greatly reduced the severity of the illness. https://www.grassrootshealth.net/blog/vitamin-d-treatment-covid-19-patients-nearly-erased-need-icu-admission/
Vitamin D counteracts the coronavirus through anti-inflammatory effects and suppression of the so-called “cytokine storms,” which are an over-reaction of the immune system.
But only recently identified is another effect that may explain the importance of Vitamin D in warding off Covid19. Studies published in May 2020 show that the virus attacks the vascular endothelium, the inside surface of blood vessels. This article is an overview, with links to technical papers. https://www.sciencetimes.com/articles/25872/20200529/coronavirus-respiratory-disease-change-everything.htm and also https://rcm.imrpress.com/article/2020/2153-8174/2153-8174-21-3-339.shtml A paper published in 2015 announced the discovery that Vitamin D3 – cholecalciferol – has a direct beneficial effect on the vascular endothelium. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140370 And it is important to know a key fact - that cholecalciferol has a circulating half-life in the body of only 12 to 24 hours https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849670/. Therefore, to consistently protect the vascular endothelium, one needs daily sun exposure or daily supplementation. This fact explains the widely varying results of Vitamin D trials for various health conditions including Covid-19. Most do not use daily doses (and often the dosage is too small and, depending on the condition, trial durations are too short).
These studies tell us that Vitamin D reduces susceptibility to Covid19, and diminishes its severity if you get sick. They indicate that, like influenza, the ebb and flow of Covid19 is governed by sun exposure, Vitamin D and people’s innate immunities.
But there is more to this story. Here in Minnesota, after the initial late-winter outbreak, hospitalizations and deaths declined as we transitioned to a warm and sunny 2020 summer when we spent more time outdoors in the sunshine wearing fewer clothes. Then, as winter approached, we got less sun exposure. Vitamin D levels in the population diminished, with consequent weakening of the innate immune system and increase in illness.
Yet at the end of 2020 the pandemic seemed to be ending. Several indicators - cases, hospitalizations and deaths – turned downward in November and December 2020. https://healthy-skeptic.com/2021/01/06/a-chart-view-of-epidemic/
This happened despite the fact that we were heading into the darkest, coldest part of the winter, where the innate immunity/Vitamin D model of Covid19 incidence and severity says that numbers of cases and deaths should be trending up. Why the decline? We cannot attribute it to vaccinations, because the first jab in Minnesota was on December 15 https://healthy-skeptic.com/2021/04/19/whos-vaccinated/. Given that it takes a month to acquire immunity, and significant numbers of Minnesotans were not vaccinated until 2021, it is evident that other factors were causing the decline in Covid19.
A similar pattern, where numbers of new cases and new deaths peaked before January 2021, is seen in many other states. https://www.worldometers.info/coronavirus/country/us/
It looks like the virus ran out of people to infect.
There is reason to believe that most people are immune to Covid19. This became apparent right at the beginning of the pandemic when there were two well-publicized shipboard outbreaks of Covid19. The first was in January 2020 aboard the cruise ship Diamond Princess, and the second was in March aboard the US aircraft carrier Theodore Roosevelt. Despite optimal conditions for the spread of the disease, government reports show an infection rate of 18 percent on both ships
https://wwwnc.cdc.gov/eid/article/26/11/20-1165_article and https://pubmed.ncbi.nlm.nih.gov/33001200/
These outbreaks were very early in the pandemic when nobody took precautionary measures, yet over 80 percent of the people on both ships tested negative. They did not contract the virus. They were demonstrably immune.
Here in Minnesota, we have tested 14,457,686 people (many, more than once, given Minnesota’s population is 5.7 million) and found 871,203 people who tested positive. https://www.health.state.mn.us/diseases/coronavirus/situation.html (19 November 2021.) That’s 15 percent of the state’s population, approaching the 18 percent incidence of infection observed aboard the Diamond Princess and the USS Theodore Roosevelt.
Worldometers.info publishes data about the number of people testing positive per million in the column titled “Tot Cases/ 1M pop” (a 20 percent incidence would result in 200,000 “Tot Cases/ 1M pop.”) There are only 5 small countries – Montenegro, Seychelles, Andorra, Gibraltar and Georgia – and one state in the US – North Dakota - where more than 20 percent of the populace has tested positive. In Finland, about 3.3 percent of the population has tested positive.
This analysis indicates that the pandemic could have been substantially mitigated if officials had recognized the importance of maintaining Vitamin D levels in the winter by supplementation.
Death rates in the higher latitudes could have been reduced by 90 percent.
This is not idle speculation. Worldometers.info publishes a deaths-per-million-of-population statistic that yields interesting insights. Countries in higher latitudes have higher death-rates-per-million due to less sun exposure, especially in the winter: UK – 2,102, USA – 2,369, France – 1,809, Poland – 2,128, Minnesota – 1,645 (19 November 2021).
Yet as noted at the beginning of this essay, Finland - one of the most northerly countries in the world – has a dramatically lower death rate, only 225 per million.
How can this be? If the innate-immunity-Vitamin-D model of Covid-19 is sound, then should not Finland experience very high levels of Covid-19, especially in the winter? As I noted at the beginning, the low death rate indicates that the Finns are mostly immune to Covid19, and I propose that this is the reason why:
Finland is the only country in the world, as far as I can tell, that has a national policy for supplementation with Vitamin D. https://www.iadsa.org/mind-the-gap/english/finland
Ninety percent (90%) of the population has serum levels of Vitamin D greater than 20 ng/ml and around half the population has levels greater than 30 ng/ml. 20-30 ng/ml is considered “adequate.” For comparison this 2014 insurance study found that 90% of US samples tested showed levels below 30 ng/ml. https://pubmed.ncbi.nlm.nih.gov/25816469/
Finland provides compelling empirical verification that Vitamin D supplementation can diminish the worst effects of Covid19.
By now it should be obvious what you can do to protect yourself from the coronavirus. Fortify your innate immunity. Take a daily dose of Vitamin D3 and to keep it up until summer and then get daily sun exposure (or continue to take supplements). Vitamin D3 is available over-the-counter at drug and grocery stores. How much Vitamin D3 should people take? This paper provides a recommendation (and a lot of information). https://pubmed.ncbi.nlm.nih.gov/32252338/.
Finally, keep this fact in mind – nearly all the cells in the body have nuclear and membrane Vitamin D receptors. This suggests that Vitamin D is essential to the proper function of a wide range of tissues and organs, and that Vitamin D deficiency may be related to a wide range of illnesses.
This analysis presents a framework in which we can understand the incidence and severity of Covid19. But we are now left with a new puzzle – what happened to influenza?
The sharp-eyed reader may observe that several Scandinavian countries, not just Finland, saw lower death rates from Covid19 than the rest of Europe.
Here are the recent death rates per million among the Scandinavian countries: Norway-182, Sweden-1480, Finland-225, Denmark-481, Iceland-99. https://www.worldometers.info/coronavirus/ 19 November 2021.
Except for Sweden, death rates in Scandinavia are much lower than their European neighbors (and Minnesota), despite no meaningful sun exposure for half the year.
Besides Finland’s program of supplementation, is there another source of Vitamin D?
People in Scandinavian countries consume a lot of fatty fish, such as herring, salmon and trout, which are a natural dietary source of Vitamin D. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2698592/ and https://www.sciencedirect.com/science/article/pii/S0160412020322777?via%3Dihub. One 4-ounce serving of salmon on average contains 1000 IU of Vitamin D. From my own experience I know that cooked, smoked and pickled fish are served at every meal in Norway.
Within the Scandinavian sphere, perhaps the real question is why is the death rate so much higher in Sweden? Sweden has a large immigrant population, many of whom are dark-skinned, which is a risk factor for Vitamin D deficiency at higher latitudes. https://www.bmj.com/content/368/bmj.m1101/rr-10 However I have not been able to find case, hospitalization or death rates for immigrants in Sweden, so it remains a hypothesis.
Excellent analysis! I have been a vitamin D3 proponent for several years and have noted that I no longer get severe respiratory infections like I used to. I would argue that the “adequate” levels between 20 and 30 are actually inadequate. This chart shows that the optimum levels for disease prevention are between 40 and 60. (My D3 level typically ranges from mid 50s to 70.)
https://www.grassrootshealth.net/document/disease-incidence-prevention-chart-in-ngml/