We are unlikely to ever find out, because we won't have a reason to give everyone antibody tests
Los Angeles → Catalina Islands → Ensenada → Los Angeles
> and were there lots of mainland Chinese people on it?
I mean, I didn't exactly go around asking people "are you from China?", but based on the number of people who sounded like they were speaking Mandarin I'd tentatively answer "yes".
> Sadly the symptoms for CoVid-19 are pretty common across a variety of diseases, so “flu-like but not flu” doesn’t necessarily point to this.
Indeed, which is why I'm still at least somewhat skeptical. Still, it's hard to rule it out, especially given the relatively-severe symptoms (not the absolute worst I've felt, but it was pretty bad).
That said, you'd be surprised what draws tourists from mainland China; Las Vegas and Reno (for example) both get plenty of Chinese tourists looking specifically to gamble, and I'd imagine the ship's onboard casino to have a similar appeal. Plus, there were plenty of other tourists from long distances, too, both from within the US (East Coast) and from Europe and Australia (from what I gathered from the people whom I did talk to). So evidently there were at least some non-Chinese tourists flying thousands of miles for it; seems reasonable that some mainland Chinese tourists might, too.
No "massive uptick" yet, but there are quite a few every week, so it could be that it's still blending in with non-COVID pneumonia cases.
Indeed. There are typically above 3000 deaths/week due to Pneumonia and 200/week due to influenza at this time of year. We had a smallish spike in mid-late January, where for 3 consecutive weeks, deaths were above trend at nearly 4000 & 400 per week.
If you assume a 1% mortality rate for COVID, and you assume all deaths are due to pneumonia, and you assume the entire late-January spike is due to COVID, that could be hiding 300,000-400,000 US cases. (To be clear, those are all questionable assumptions! The mortality rate could easily be either lower or higher, a meaningful fraction of deaths might not show as pneumonia or influenza, and it is normal for there to be a moderate spike above trend at some point in the flu season)
That doesn't mean that there were or weren't a few hundred thousand cases in that time -- it just means that some significant number of cases could easily hide in "routine-looking" spikes in the graph.
This does mean, though, that it is unlikely that everybody who got "the really bad flu" that's been going around this year actually had COVID -- but, especially if you live in a place with lots of people who travel to China regularly (like I do!), it isn't unreasonable to wonder if that "really bad flu followed by a lower-respiratory-tract infection that tested negative for influenza" you got in late January/early February wasn't really COVID.
(Remember, though, that while the rapid influenza test has a pretty low false-positive rate, it's got about a 50% false negative rate -- so testing negative shouldn't lead you to assume it isn't influenza)
Critical cases and fatal cases are way more likely to be detected for this reason -- but during the 3 weeks I was talking about, it was believed that there was no COVID in the US, except for folks evacuated from China to quarantine sites.
During that time unexplained pneumonia leading to death -- especially in an older individual -- would likely not have been thought to be COVID, and would just have gone on the books as pneumonia.
Thankfully all of us seemed to get over it without much complication, and it doesn't seem like very many of the people we've since interacted with have come down with it. We might very well have just been lucky, though.