Thread by @jmcrookston

Ah, opening up yet another random PDF on my computer and spending 5 minutes skimming it. Yet another hit

This time, we will learn that influenza can transmit as aerosols through the air and infect at very low TCID50s (low dose).

Let's go!

From 1966. #influenzaisairborne!

Since we discovered flu is a virus, we wanted to know how it transmitted. Studies found through the air, but used high doses.

So authors wanted to go low.

No, not like that. Low dose.

Authors used a system that approximated coughs, etc.

Methods:

Blah blah serial dilutions were prepared. Blah blah breathe it in in 52 seconds. Blah blah passive voice stinks.

Let's skip. YOU read the thing if you're into methods.

Results: Now we're cooking!

So, some people had illness. The ones with the + signs. Nobody else did.

INTERESTING 1: The antibody test was positive, even though no signs of illness, on the high TCID50 doses.

INTERESTING 2: Subject 20 threw up 30 times and had the highest antibody response, although receiving a small dose.

Discussion:
- authors caveat that results crude, system limits not known.

- authors then calculate the TCID50 for influenza when administered by aerosol.

Note that the TCID50 (the concentration of virus that is required to infect 50% cell plates exposed to it) accorded with mouse studies.

INTERESTINGLY: It took a LOT less to infect by aerosol than nasopharyngeally (the box behind the nose).

Took ~0.6 to 3 by aerosol.

~30 nasopharyngeally.

Conclusion was small amounts of virus can infect. This was interesting in light of the recent (in 1970) discovery that natural transmission can release such small amounts.

Also, that low levels of neutralizing antibody may not protect against illness.