HAL Makes List With Most Noro Outbreaks

One should take into account the relative size of each cruise lines fleet. If you normalize for the size of the fleet you get.

 

Celebrity 15 incidents/ 11 ships 1.36

Princess 15 incidents/ 18 ships .83

Cunard 4 incidents/ 3 ships 1.33

Royal 10 incidents/ 24 ships .41

Holland 10 incidents/ 16 ships .62

 

 

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The Crown Princess alone as had multiple outbreaks of the Noro since January and at least two complete sanitizings on turn around days in San Pedro including one yesterday delaying boarding and sailing. Her cruises this spring have been along the California coast, 3, 4 and 7 days. Don't know if that makes a difference or not.

The Crown Princess alone as had multiple outbreaks of the Noro since January and at least two complete sanitizings on turn around days in San Pedro including one yesterday delaying boarding and sailing. Her cruises this spring have been along the California coast, 3, 4 and 7 days. Don't know if that makes a difference or not.

Keep in mind that cruise lines do not wait for the 2% or 3% levels before taking preventive action. They start going to code red at very low levels (just a couple of passengers). If they see any kind of a trend (increasing infection/reporting rates, continuation from one cruise to the next, etc.) they will go to enhanced sanitation. Far beyond prevention measures that take place in the general public.

Keep in mind that 23 million people come down with Noro in the US each year. Now if that was evenly distributed across the population of 330 million and spread evenly across the year then the odds that an individual with Noro is on a cruise of 3000 people on departure day would be .57 (57%).

(23 million/365) = patients per day = 63,013 patients per day/330 million = ratio of patients to population per day =.00019 (.019%) X 3000 number of passengers on cruise ship = .57 (57%).

Now this is a very rough back of a napkin type calculation just to show relative scale. To get real numbers a lot more things would have to be taken into account such as that the cases are not evenly distributed (half in managed care facilities) through out the population or through the year (peak in the March/April in Northern hemisphere, and September/October is southern. A patient is infectious for more then one day. Ill patients might be too sick to travel and board, etc. But it does give the idea that if you cruise you will encounter Noro, just as if you go out of your house you will eventually encounter it, and that cruise ships do a pretty good job at containing it.