Flu Season Runs on a Virus

@DavidWolfe posted on September 19: "It's not "cold and flu season." It's low vitamin D, high stress and too much sugar season." About 63,500 people saw it, and nearly 5,000 hit like, presumably between sips of a turmeric latte and a sponsored gummy unboxing.

Influenza is a virus. Labs swab noses for it, sequence it, and track its strains every week of the year with the intensity of Swifties decoding an Easter egg. CDC puts its yearly toll from 2010 to 2025 at 9.4 to 51 million illnesses, up to 710,000 hospitalizations, and between 6,300 and 52,000 deaths. Pumpkin spice season gets far less paperwork.

Then 2020 ran the experiment for us. Americans masked, stayed home, and stress-baked through the sourdough era like contestants on a very sad Bake Off, sugar very much included. In the 2020–21 season, 0.15% of lab specimens tested positive for flu, down from 16.8% the year before. Nobody's vitamin D levels collapsed and rebounded on cue. The bug simply couldn't hop from one person to the next.

The sunshine vitamin does have a real résumé. A 2017 BMJ meta-analysis pooled 25 randomized trials with 10,933 people and found supplements trimmed acute respiratory infections from 42.2% to 40.3%. About 33 people need a pill for one of them to dodge a cold, and most of the gain went to people who were badly deficient. Fixing a deficiency is worth doing, and it moves the needle by roughly two points, which is a supporting role at best.

Calling flu a lifestyle problem tells people their sniffles are a personal failing and their flu shot is optional homework. Influenza, for the record, doesn't follow wellness accounts.

Verdict: 3 False. Flu is a contagious virus, and vitamin D, stress, and sugar shift the odds a little at most.

Sources: CDC flu burden estimates · Martineau et al., BMJ 2017