In many studies on respiratory infections like the common cold, flu, asthma and pneumonia, there is a significant seasonal fluctuation with most incidences being in the cooler and drier months of the year (Fagbo et al., 2017). The causative link of much higher respiratory infections in winter is due to a vitamin D deficiency. In fact, some studies have shown that a vitamin D deficiency is THE cause of epidemics of respiratory infections in winter (Cannell et al., 2008).
I have crunched the numbers again on the coronavirus statistics, again to look at the differences between the hemispheres. With more data available, I get a similar picture to before, but showing an even more significant outcome. My findings are:
North Equator South
No. countries affected 67.5% 8.1% 24.3%
No. COVID-19 incidences 96.8% 1.7% 1.4%
No. COVID-19 deaths 98.8% 1.0% 0.22%
Note the huge difference in incidences and deaths between the northern hemisphere and the south. Yes 88-90% of the world’s population live in the northern hemisphere, which can account for some of the difference, but certainly not all of it.
Some more statistics and more differences in the seasonal influence of coronavirus:
Northern Hemisphere Southern Hemisphere
Average mortality rate* 2.04% (range: 0 - 10.10%) 0.57% (range: 0 – 2.07%)
Australian mortality rate 0.39%
* Using data from countries with over 100 incidences (as at 26/03/2020)
There is a 400% increase in coronavirus mortality rates in the northern hemisphere compared to the south. And a 500% difference in the maximum mortality rates between the hemispheres. Australia's mortality rate is very low overall, and when compared to other southern hemisphere countries, and far less than those in the north.
Why is there such a difference between the north and south? The northern hemisphere is coming out of their winter, the traditional season of the highest seasonal respiratory infections, and into spring, another time for seasonal respiratory issues with asthma and hayfever. The attached table shows the differences in the amount of time needed in the Aus capital cities to make the same amount of vitamin D in winter vs summer! In summer, there's not much of a difference, but a huge difference in time needed in the sun in winter to make vitamin D, especially the further from the equator you are located. This is the problem that the northern hemisphere countries are having.
Low vitamin D levels, from low sun exposure in the colder months, is a cause of low immune system function in winter, and a major cause of respiratory infections and outbreaks like we are seeing (Cannell et al., 2008). Vitamin D is THE key! Vitamin D is the key to prevention and treatment in this pandemic. Conversely, as we in the southern hemisphere are coming out of our summer, our vitamin D levels should be optimal (if we don't use sunscreen every 5 minutes and don't avoid the sun!) to keep us healthy and our immune systems strong going into the colder months. That's the ideal situation, but I see very low vitamin D levels in many clients, even in summer in Qld!
As I keep saying, in order to fix health issues, you must “FIND THE CAUSE AND FIX THE CAUSE”! Normally I would recommend getting your vitamin D levels tested first to check, and then see if you are deficient and need to supplement. At this time with pathology labs working overtime to do coronavirus testing and more on those in hospital, there’s a delay for waiting on pathology results. I don’t think you should wait – get more sun time daily (without getting sunburnt!) AND take a good quality vitamin D supplement daily. You need vitamin D3 (NOT vitamin D2, so check the product label) from a good source, in a capsule form, or oral drops or oral spray, or in cod liver oil! There’s very little harm or risk in taking a vitamin D supplement daily at the moment and continue this while this pandemic is still around or until after winter (for those of us in the southern hemisphere).
Keep up with good hygiene practices, but more importantly, support your immune system better to help it prevent and fight this or any other infection! If you have to isolate yourself, through government mandates or due to infection, DON’T just stay inside! Get outside in the sun in your garden! Get some direct sun exposure on your skin to make more vitamin D (remember that glass blocks the UV-B light needed to make it), as it is the most powerful immune system booster we have!
Cannell, J.J., Zasloff, M., Garland, C.F., Scragg, R., & Giovannucci, E. (2008). On the epidemiology of influenza. Virology Journal, 5 (29). DOI: 10.1186/1743-422X-5-29
Fagbo, S.F., Garbati, M.A., Hasan, R., AlShahrani, D., Al-Shehri, M., AlFawaz, T., Hakawi, A., Wani, T.A., Skakni, L. (2017). Acute viral respiratory infections among children in MERS-endemic Riyadh, Saudi Arabia, 2012-2013. Journal of Medical Virology, 89 (2):195-201. doi: 10.1002/jmv.24632