Two Weeks Mixing With Flu Patients, Nobody Caught The Flu (Here’s Why!)

Indoors, close quarters, no masks, no latest flu vaccine, so what was the secret?

Influencing the influenza

First, let’s be clear:

• Being outdoors is better for reducing flu transmission than being indoors
  • In other words, do avoid enclosed spaces with lots of people where possible, because this is a big factor. In fact, while people think of cold weather as increasing the risk of colds and flu, the main real difference comes from “when it’s cold, people spend more time indoors in close quarters together with the windows closed”. You can learn more about that here: The Pathogens That Came In From The Cold
• Facemasks are better for reducing flu transmission than being unmasked
  • Importantly, masks do help, but are more important on an epidemiological level than personal (i.e. they protect society more than they protect the wearer), and they are impractical in many circumstances, and use of them is very low in most countries. So in other words: they’re good! But may be a lost cause at least for the time being. See also: Mythbusting The Mask Debate
• Vaccination is better for reducing flu transmission than being unvaccinated
  • Vaccines are considered the “gold standard” against COVID and many other infectious diseases, for their very high rate of efficacy, clear science, and at least moderately lasting effects (i.e., it’s not something like handwashing*, which must be redone very frequently). Since vaccines are not without their popular misunderstanders, we have written a little about that, here: Vaccine Mythbusting

That being said, none of those things were the reason in this case.

So, what exactly was the case?

First, the setting: researchers (Dr. Jianiu Lai et al.) ran a controlled hotel-based experiment in which young adults with confirmed influenza infections spent two weeks indoors with healthy middle-aged adults, yet no transmission occurred.

And, what was the explanation?

Coughs and sneezes spread diseases: a big factor here was that infected young adults had high viral loads in their noses but rarely coughed, which greatly limited how much virus entered the air.

Reproducing the outdoors, indoors: while the experiment was all self-contained with no access to the outside world, fan heaters and dehumidifiers rapidly mixed the room air, diluting viral particles and reducing inhalation exposure.

You can read the paper itself, here: Evaluating modes of influenza transmission (EMIT-2): Insights from lack of transmission in a controlled transmission trial with naturally infected donors

So if you’d like to benefit in the same way, then (besides what we already talked about above, consider:

Why Some People Get Sick More (And How To Not Be One Of Them)

And for the matter of indoor climate control specifically (in health terms, when it comes to ventilation, temperature, humidity, and pollution*, see:

What’s Lurking In Your Household Air?

*You might be thinking “pollution, indoors?”, and yes, pollution indoors, for two main reasons:

• You May Have More Air Pollution In Your Home Than In The Street
• Why Your Air Is Probably Worse Quality Than You Think ← half of the US has dangerously polluted air, and the air outside eventually becomes the air inside (assuming you live in a house, not a bubble with recycled air)

…but those things are of course a separate matter to the main topic of flu management.

So for a more holistic approach, we invite you to check out: Seven Things To Do For Good Lung Health!

Want to learn more?

For a deeper dive into immunity, here you go:

The 21-Day Immunity Plan – by Dr. Aseem Malhotra

Take care!