Vaccination or higher vitamin D levels alone drive diagnosed influenza infection levels under 1%

An investigation by this reporter reveals hidden data not apparent in a recent vitamin D/influenza study.  [Clinical Nutrition 2016]

A study was conducted in Japan 3327 employees (mean age 37 years) at companies in Japan, 5.5% (182 subjects) whom were doctor-diagnosed with the flu over a 5- month (winter) period.  The flu vaccination rate was 26.3% among workers who were diagnosed with flu versus 27.5% among those who didn’t.  There were 217 unvaccinated subjects out of the 3327 total subjects (6.5%).

Vitamin D blood levels were typically low, ~22 nanograms per milliliter of blood in the workers as a whole.  Researchers compared a blood vitamin D level of under 20 ng/ml , 20-30 ng/ml and over 30 ng/ml.   Data on subjects where flu diagnosis was confirmed by a diagnostic kit were also segregated.

The chart below is what The Vitamin D Council considers adequate vitamin D blood levels.

  Vitamin D Council
Deficient 0-30 ng/ml
Insufficient 31-39 ng/ml
Sufficient 40-80 ng/ml
Toxic >150 ng/ml


Critics would quickly say all of the subjects in the first two groups (below 20 ng/ml and 20-30 ng/ml could be considered vitamin D deficient or at least inadequate.  This is confirmed in the chart below where the group with mid-range vitamin D levels actually experienced a higher rate of infection (1.77% lowest vitamin D level; 4.18% mid-range vitamin D level).

The study confirmed the effectiveness of flu vaccination among generally healthy working-age adults.  The rate of influenza was 3.37% in vaccinated subjects and 34.1% among unvaccinated subjects.  However, there is another striking finding in this report.

Among the vaccinated, vitamin D levels over 30ng/ml reduced the risk for diagnosed influenza by almost 3-fold (0.86% to 0.38%), which means maintenance of vitamin D levels is beneficial even among the vaccinated.

What more, both vaccination and vitamin D alone (no vaccination) drove diagnosed influenza infection risk below 1%!

Oh, what researchers keep hidden from the public.


Vitamin D Levels & Diagnosed Influenza
Vitamin D blood levels
Under 20 ng/ml 20-30
Over 30 ng/ml Total
# diagnosed flu 59/3327 106/3327 14/3327 179/3327
% diagnosed flu 1.77% 3.18% 0.42% 5.5%
# diagnosed flu 27/3110 66/3110 12/3110 105/3110
% diagnosed flu 0.86% 2.12% 0.38% 3.37%
# diagnosed flu 32/217 40/217 2/217 74/217
% diagnosed flu 14.74% 18.43% 0.92% 34.1%

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