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Comment by rossdavidh | Hacker News Reader

"A 10% prevalence rate on a flight is unbelievably high. Like defies imagination..."

No, it isn't. Past experiments (aimed at measuring the impact of elderberry on cold virus resistance, btw) found about 10% of people on a flight getting infected with a respiratory virus.

https://ergo-log.com/elderberries-help-against-colds.html

It wasn't a coronavirus, but my point is that a respiratory virus spreading to 10% of the people on a flight is so common, the researchers could just pick a normal plane flight and find 10% infection. So, for a virus to spread to 10% of the people on a plane flight is not "unbelievably high", it's apparently not uncommonly seen for other respiratory viruses.

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You only test positive on PCR after a few days (at least for the Delta variant). So the infections can't really have happened on the plane, but before. And at that point 10% would be unbelievably high if the people on the plane were all independent and not in previous contact.

It's a bit hard to put this number into context though if you don't know anything about the passengers. It would be much more plausible if e.g. a large part of the passengers were in the same hotel before or something like that.

Unless Omicron is different, which is possible and consistent with other evidence. It's spreading 500% faster than the original strain did; Delta was only 70% faster. The two asymptomatic Hong Kong patients both have sky-high viral loads.

That's why this data is so alarming. Either you've got a 10%+ base rate in the population and they all skipped (or false-negative) a pre-boarding PCR test. Or Omicron spreads fast enough that it can infect 10% of a plane during a 12-hour flight and multiply enough to show up on a PCR test upon landing. Or the 61 cases knew each other beforehand (same hotel, same tour) and it's bad for that travel operator but better for public health, which is why they're trying to get the facts on that.

But, if it's actually true that symptoms are milder than those of Delta (which has been the indication), should we be embracing Omicron with open arms?

Just hypothesizing here - it'll take a good while until we have actual useful data.

The study you are linking to was not comparing flying to not flying, only two different groups flying. Consider that the baseline rate of colds in a seven day window (their before travel to after travel survey window) is very high:

https://www.cdc.gov/mmwr/volumes/69/wr/mm6914a5.htm

Interesting! I had no idea it was that high normally.

When I saw someone with a cold going on the same plane as myself, I could be 100% sure I will get off of the plane with a cold... So it seems like sensationalising indeed, at least from my anecdotal experience.

Yeah anecdotally I’ve hopped on a couple planes this year where masking is required. Normally my wife and I get sick from the plane. But since we’ve been wearing KN95s the whole time starting when we get to the airport we haven’t been getting sick at all.

Could be that they wouldn't let someone with a visible cold on a plane. It wasn't the case in the past.

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