Cruise Ship Diamond Princess

| March 20, 2020


Diamond Princess

The last group of about 130 crew members got off the Diamond Princess last Sunday, vacating the contaminated cruise ship and ending Japan’s criticized quarantine that left about one fifth of the ship’s original population infected with the new virus.

The British-flagged, U.S.-operated cruise ship carried an infected passenger part way before returning to its home port in Yokohama, near Tokyo, on Feb. 3. Of the 3,711 passengers and crew members on board, 705 were infected on the ship, triggering international criticism of the quarantine and Japan’s disease control capability.

Warning, some math ahead. I checked so you don’t have to. Poetrooper sends:

Diamond Princess Mysteries

Willis Eschenbach

OK, here are my questions. We had a perfect petri-dish coronavirus disease (COVID-19) experiment with the cruise ship “Diamond Princess”. That’s the cruise ship that ended up in quarantine for a number of weeks after a number of people tested positive for the coronavirus. I got to wondering what the outcome of the experiment was.

So I dug around and found an analysis of the situation, with the catchy title of Estimating the infection and case fatality ratio for COVID-19 using age-adjusted data from the outbreak on the Diamond Princess cruise ship (PDF), so I could see what the outcomes were.

As you might imagine, before they knew it was a problem, the epidemic raged on the ship, with infected crew members cooking and cleaning for the guests, people all eating together, close living quarters, lots of social interaction, and a generally older population. Seems like a perfect situation for an overwhelming majority of the passengers to become infected.

And despite that, some 83% (82.7% – 83.9%) of the passengers never got the disease at all … why?

Let me start by looking at the age distribution of the Diamond Princess, along with the equivalent age distribution for the entire US.


Figure 1. Number of passengers by age group on the Diamond Princess (solid) and expected number of passengers given current US population percentages (hatched).

When as a young man I lived in a port town with cruise ships calling, we used to describe the passengers as “newlyweds and nearlydeads”. Hmmm … through some improbable series of misunderstandings and coincidences, I’m in the orange zone now … but I digress …

In any case, Figure 1 shows the preponderance of … mmm … I’ll call them “folks of a certain distinguished age” on the Diamond Princess. Folks you’d expect to be hit by diseases.

Next, here’s the breakdown of how many people didn’t get the virus, by age group:


Figure 2. Percentage of unaffected passengers on the Diamond Princess. “Whiskers” on the plot show the uncertainty of each percentage.

In addition to the low rate of disease incidence (83% didn’t get it), the curious part of Figure 2 for me is that there’s not a whole lot of difference between young and old passengers in terms of how many didn’t get coronavirus. For example, sixty to sixty-nine-year-old passengers stayed healthier than teenagers. And three-quarters of the oldest group, those over eighty, didn’t get the virus. Go figure. Buncha virus resistant old geezers, I guess …

Next, slightly less than half the passengers (48.6% ± 2.0%) who got the disease showed NO symptoms. If this disease is so dangerous, how come half the people who got it showed no symptoms at all? Here’s the breakdown by age:


Figure 3. Percentage of Diamond Princess passengers who had coronavirus but were symptom-free. There was only one illness among the youngest group, and they were symptom-free. As in Figure 2, the “whiskers” on each bar of the graph show the uncertainty.

Again, a curious distribution. Young and old were more likely to be symptom-free, while people in their 20s, 30s, and 40s were more likely to show symptoms. Who knew?

There were a total of 7 deaths among those on board. All of them were in people over seventy. So even though the generally young were more likely to show symptoms if they had it, it hits old people the hardest.

Finally, according to the study, the age-adjusted infection fatality rate was 1.2% (0.38%–2.7%). Note the wide uncertainty range, due to the small number of deaths.

For me, this is all good news. 83% of the people on the ship didn’t get it, despite perfect conditions for transmission. If you get it, you have about a 50/50 chance of showing no symptoms at all. And the fatality rate is lower than the earlier estimates of 2% or above.

It is particularly valuable to know that about half the cases are asymptomatic. It lets us adjust a mortality rate calculated from observations, since half of the cases are symptom-free and likely unobserved. It also gives a better idea of how many cases there are in a given population.

To close out, I took a look at the current state of play of total coronavirus deaths in a few selected countries. Figure 4 shows that result.


Figure 4. Deaths from coronavirus in four countries. Note that the scale is logarithmic, so an exponential growth rate plots as a straight line. Blue scale on right shows the deaths as a percentage of the total population.

At this point at least, it doesn’t appear that we are following the Italian trajectory. However … it’s still early days.

Finally, a plea for proportion. US coronavirus deaths are currently at 67, we’ll likely see ten times that number, 670 or so, might be a thousand or three … meanwhile, 3,100 people die in US traffic accidents … and that’s not 3,100 once in a decade, or 3,100 per year.

That’s 3,100 dead from auto accidents EACH AND EVERY MONTH … proportion …

My best to all on a day with both sun and rain here, what’s not to like?

w.

Methods, data and comments can be found here: WUWT
Thanks, Poe

Category: China, Guest Link, Health Care debate, International Affairs

18 Comments
Inline Feedbacks
View all comments
Jeff LPH 3, 63-66

We were on a seven day cruise last Jan out of Ft. Lauderdale and into Comphibron 8’s old Carib stomping grounds on board the Princess Regal. This was the ship that was used for the love boat TV series filming. I hate the cold and had to wear my light FD jacket all over the place. I only warmed up when the three of us danced around on the main deck at night. I told the girls that this was my last cruise. Too cold for me. Even the passage ways were colder than a well diggers ass in the Klondike.

26Limabeans

The only ship I ever sailed on was the
Marthas Vineyard ferry out of Woods Hole.
I was just a kid but knew right there I
didn’t want anything to do with the Navy.

aGrimm

Water weenie and a couple more below. Go Navy! – but think twice about becoming a Navy corpsman as you might end up pounding the ground with the Marines. 🙂

5th/77th FA

Glad I didn’t have to do the math. Figure if I catch it, I will either get over it or die. Does that make it a 50/50 chance?

I scored high enough to join the Navy in 1971, even tho there was a waiting list to get in. Passed up that opportunity. I can swim fairly well, but not far enough to get back to dry land. My time of floating is not that great either. Took the big ship from Souda Bay Crete to Athens in ’72. That was more than enough sailing of the deep blue sea for me.

Poetrooper

The reason I gave Ed a heads-up on this study was that it demonstrates what so many of us have been saying all along, that this panic over this bug is way out of proportion to the actual threat.

I sent another, even more interesting, link but Ed feels it needs more corroboration. There are multiple reports circulating out there that there are actually two variations of this COVID-19 virus with one being a much more serious, possibly weaponized form.

An Indian laboratory supposedly discovered that this more lethal form had HIV proteins attached to render it more destructive. When that report was made public in the Indian media, along with the added speculation that these alterations had been done in the Chinese bio-weapons labs in Wuhan, the Chinese government pressured the Indian government to take down the reports, which it apparently did.

Interestingly, some of these accounts are reporting that if one contracts the lesser form of COVID-19 and survives, he is then immunized against the more lethal form should he be subsequently exposed.

There’s more here:

https://www.redstate.com/stu-in-sd/2020/03/16/wuhan-virus-and-bioweapons-the-past-is-prologue/

Ol’ Poe is not signing on to this “theory” until more evidence comes to light. However I do find it quite interesting considering the “interesting times” in which we find ourselves. Remember the old Chinese curse, “May you live in interesting times,” meaning “I hope your life is a frickin’ disaster.”

5th/77th FA

SON.OF.A.BITCH!!!!!! Dahell did I FIRST say when this sh^t FIRST started to be talked about? The effing ChiComs are neck deep and dirty as hell over this crap and have been enabled by the domestic enemies of our Republic. I say nuke the phuquers from space, and tie all the sumbitches that did the insider trading sell off to the nose cone of the warhead. Grrr…sometimes I hate it when I’m proven right.

No telling what else is out there that has been covered up.

Thanks Poe!

11B-Mailclerk

China is going to have some serious explaining to do. So are all its paid shills, here in the USA, and the unpaid sycophants too. The CCP is going to try to spin, dodge, and bald-face-lie their way out of this one.

No way.

The CCP paid agents and CCP fan club also need to know we wont be forgetting this one. Y’all’s credibility is now “TP stains”. Own it. Deal with it.

Slow Joe

Before we go to war with China over this, we need more evidence.

Anyone has any ideas on how to beat a nuclear power before it can use its nukes?

5th/77th FA

Slow Joe, my comment was more speaking figuratively v literally, tho what they have done IS an act of war. The only difference here and what happened at Pearl Harbor or on 911, is that it was done with a bug instead of violence. There has been plenty of evidence throughout the last several years of the Chicoms attacking us in various ways. We have handed over most of our manufacturing, food packaging, medicine making, the list goes on. This is not the FIRST bug to come out of there. And what about the other contaminates that we have seen over the years. Poisoned dog food, lead paint on toys, hell an entire thread on this subject just the other day. They started out slapping us with swimming pool noodles and are now up past slapping us with 2 X 4s to beating us with 2 X 12s. Read these articles that people are posting, read the comments from the ones that have seen up close and personal what the enemies of our Republic are doing. You’re a smart guy, think about it. As an Infantryman, you know what the best tactic is to defeat your enemy. Divide, bring every weapon to bear, and conquer. Some of us have fought the communist threat for all of our lives. The Cold War has never ended, just the primary enemy has changed. If you don’t think that the ultimate goal of the ChiComs is to destroy our way of life, then I have a bridge leading to ocean front property to interest you in.

Slow Joe

Again,

Does anyone have any ideas on how to beat a nuclear power before it can use its nukes?

I completely agree with all your arguments, however, wars are not won with internet bravery or liquid valor.

We are not talking of Iraq or Afghanistan here. We are talking of a nuclear power, and in my opinion, the only dude that ever beat the shit out of a nuclear power was Ronaldus Magnus, and he never fought the Soviets head-on. He stab them in the ribs with an economic knife and twisted it until it got through to the heart of the old Soviet Union.

Perhaps we should study how nuclear powers are defeated before we charge head-on. I am all about slaying zombies left and right, regardless of whether they are moon-god donkey-lovers or Marxist-Leninist smelly critters, but we need a solid strategy and a national commitment before I feel confident in committing our boys into a fight with the Chicoms.

11B-Mailclerk

Lather rinse repeat, adapted for current foe.

Start: recognize they are not merely weird/annoying neighbors. Recognize their active hostilities.

Undo the dumb-ass laws that flushed a generation worth of jobs overseas.

Undo other laws that rig/tilt/favor them. Tilt it the other way: in our favor.

If they up the economic game? Repudiate some or all China held debt. We hit a pothole. They crash and burn. And since their antics have already accustomed us to “pothole”, we have never been in a better position to do it.

They are terrified we might. Their internal borrowing is catastrophic vulnerable.

They import food.

Their own folk can and will make changes, which is the threat of Hong Kong.

Step one: decide we want to win and will do what it takes.

5th/77th FA

Nailed it 11B, ‘specially Step 1. Slow Joe, short answer to your question is using a massive, overwhelming FIRST Strike. Only way to ensure you will win. However, we all know that will never happen. The old theory of MAD (Mutual Assured Destruction) doesn’t really concern the ChiComs. They would welcome a counter strike, just to help reduce their population. Study up on their 100 year plan, they are a very patient people and they know our history better than most of us do. They also know that our government “turns over” every 2,4,6.8 years on the election cycles. Basically their head of state has only changed 2, at most 3 times since 1949, and each successor was hand picked. Some of us old geezers have some advantages over the younger folks. We have not only lived thru the history of the last 70 years, we studied the true history of the world as it was written before the revisionists and political correctness set in.

And no, I don’t have internet bravado or courage from a bottle. I DO have excellent reading comprehension, am very well read on the history of the world, and think that we should have our beverages in a cup made from the skulls of our enemies AFTER they are defeated.

aGrimm

If you would follow what Trump has been doing with tariffs and new trade agreements, he and his administration ARE beating the crap out of the Chinese. I recommend The Conservative Tree House for excellent analyses along these lines. Search for articles about China and you will find scores of well analyzed and reasoned presentations. There are a few other websites that discuss the US v China economics, but they tend to throw in conspiracy theories that add nothing to the discussions. The Wall Street Journal does a fairly good job but you have to subscribe to it. The one good thing that the economic war that Trump has going with China – it doesn’t involve soldiers getting killed or maimed.

aGrimm

Oops, thanks and attribution goes to AW1Ed. Don’t feel bad Poe, I also liked what you said.

JTB

aGrimm

Willis Eschenbach does a lot of analyses on WattsUpWithThat.com; principally anti-alarmism climate analyses. He also has his own website and is a most interesting fellow. The analysis presented above (thanks Poe) comes from a scientific study he is basically regurgitating, but he comes to the same conclusions that I do – the corona virus overreaction is insane. Despite my bride’s high-risk status, neither of us are particularly concerned. We are taking reasonable precautions to avoid ANY flu including the corona virus. Why are we not all that panicky? Well just count up all the stupid and failed ‘the world is coming to an end’ prophecies we have seen in the last 70 years. Idiots abound in buying into these prophecies.

Skippy

One of many reasons why I would never take a cruise
Every other month there is a breakout on one of these
Boats I don’t need anymore proof