Looking at the statistics of the countries with tested and apparently confirmed coronavirus incidences, there are:
- 83% are in the northern hemisphere, and
- only 17% is the southern hemisphere.
- 91% are in the northern hemisphere, and
- just 9% in the south or on the equator...
Well, the northern hemisphere countries are just coming out of their winter.
From past experience and reading relevant research, I know that the rates of respiratory infections like the common cold, flu and pneumonia are higher in the cooler and drier winter months, and not in summer. So it didn't surprise me to see the coronavirus taking hold during the 2019-2020 winter in the northern hemisphere.
But why do we see this seasonal variation of respiratory infections?
It's quite simple really! During winter, and especially coming out of it, it is very typical of most people to have low vitamin D levels! Vitamin D is made by our bodies from direct sunlight on exposed skin. In summer we are outside in the sun more, exposing more skin to the sun and making more vitamin D. In winter the reverse is true.
Vitamin D is a massive immune system booster! Vitamin D also reduces inflammation, reduces the rates of viral respiratory infections and influenza, and reduces lung conditions like asthma (Hossein-Nezhad & Holick, 2014; Martineau et al., 2017). Vitamin D can also offer antiviral and antibacterial actions as well as stimulating the innate immune system (which identifies and deals with unknown or new infections) (Martineau et al., 2017).
Our summer vitamin D levels should be good enough to keep our immune systems functioning well through winter and into spring when it warms again (then we start going outside with less clothes on again!). But I see more clients than not are vitamin D deficient even in summer in Qld, which is crazy!
Vitamin D deficiency, especially in winter, can be a major cause of respiratory infections (Fagbo et al., 2017) and a vitamin D deficiency amongst a large percentage of the population (which occurs in winter) is the cause of influenza respiratory infection epidemics (Cannell et al., 2008).
Flu and respiratory infection epidemics are caused by a deficiency of vitamin D! Regardless of whether you are located in the northern or southern hemisphere, get out into the sun (without getting sunburnt!) daily to make more vitamin D, and/or start getting onto your vitamin D supplements NOW for prevention! And also look at some of the other immune system supportive nutrients and herbals, and antiviral products too, as mentioned in my earlier articles!
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
Hemilä, H., & Chalker, R. (2013). Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, 1: 1465-1858.
Hossein-nezhad, A., & Holick, M.F. (2014). Vitamin D for Health: A Global Perspective. Mayo Clinic Proceedings, 88 (7): 720–755. doi: 10.1016/j.mayocp.2013.05.011
Leary, P. F., Zamfirova, I., Au, J., & McCracken, W. H. (2017). Effect of Latitude on Vitamin D Levels. The Journal of the American Osteopathic Association, 117 (7), 433. doi:10.7556/jaoa.2017.089
Martineau, A.R., Jolliffe, D.A., Hooper, R.L., Greenberg, L., Aloia, J.F., Bergman, P., Dubnov-Raz, G., Esposito, S., Ganmaa, D., Ginde, A.A., Goodall, E.C., Grant, C.C., Griffiths, C.J., Janssens, W., Laaksi, I., Manaseki-Holland, S. Mauger, D., Murdoch, D.R., Neale, R., Rees, J.R., Simpson, Jr, S., Stelmach, I., Kumar, G.T., Urashima, M., & Camargo, Jr, C.A. (2017). Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. British Medical Journal, 356: i6583. doi: 10.1136/bmj.i6583
Tamerius, J., Nelson, M.I., Zhou, S.Z., Viboud, C., Miller, M.A., & Alonso, W.J. (2011). Global Influenza Seasonality: Reconciling Patterns across Temperate and Tropical Regions. Environmental Health Perspectives, 119 (4). doi: 10.1289/ehp.1002383
van der Mei, I.A.F. Ponsonby, A-L., Engelsen, O., Pasco, J.A., McGrath, J.J., Eyles, D.W., Blizzard, L., Dwyer, T., Lucas, R., & Jones, G. (2007). The High Prevalence of Vitamin D Insufficiency across Australian Populations Is Only Partly Explained by Season and Latitude. Environmental Health Perspectives, 115 (8): 1132–1139. doi: 10.1289/ehp.9937