Norovirus: What, me worry?

By Lew Toulmin
This item appears on page 55 of the May 2013 issue.
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If you read the general press, you probably believe that the following statements are true: 

  • Norovirus is the “cruise ship disease.”
  • Your chances of getting the disease on board are pretty high, thus it is reasonable to avoid cruising.
  • The cause of the disease is insufficient cleaning and sanitizing aboard ship.
  • The absolute best way to avoid the disease is to use disinfectant gel frequently. 

I think I can show that every one of these statements is false or, at least, misleading. Along the way, I also will present you with the facts and tell you how to protect yourself from this much-publicized but poorly understood disease.

‘Cruise disease’ or ‘land disease’?

Very contagious, Norovirus is a nasty but not life-threatening virus. It is somewhat less common than the so-called “common cold.” Often called stomach flu, it has nothing to do with influenza. 

Please login or subscribe to ITN to read the entire post.

If you read the general press, you probably believe that the following statements are true: 

  • Norovirus is the “cruise ship disease.”
  • Your chances of getting the disease on board are pretty high, thus it is reasonable to avoid cruising.
  • The cause of the disease is insufficient cleaning and sanitizing aboard ship.
  • The absolute best way to avoid the disease is to use disinfectant gel frequently. 

I think I can show that every one of these statements is false or, at least, misleading. Along the way, I also will present you with the facts and tell you how to protect yourself from this much-publicized but poorly understood disease.

‘Cruise disease’ or ‘land disease’?

Very contagious, Norovirus is a nasty but not life-threatening virus. It is somewhat less common than the so-called “common cold.” Often called stomach flu, it has nothing to do with influenza. 

According to the Centers for Disease Control (CDC), norovirus “causes your stomach or intestines or both to become inflamed,” often leading to stomach pain, nausea, diarrhea and vomiting. You can get it from “an infected person, contaminated food or water, or by touching contaminated surfaces.” 

All that sounds bad, and it is, but notice that the CDC never mentioned “cruise ship.” This is because norovirus is actually quite common on land, and it regularly affects hospitals, nursing homes, college campuses and any place where people congregate. 

The best way to avoid norovirus? Wash your hands with soap and warm water. Photo: Toulmin

For example, in early 2012 a number of Northeastern colleges experienced attacks, and in 2009-2010 norovirus was the number-one culprit in infectious outbreaks in US hospitals. In fact, norovirus used to be called “Norwalk-like virus,” and it was given that name after a 1968 outbreak in a Norwalk, Ohio, school, 1,000 miles from the sea. 

Your chances at sea

According to the CDC, only 16 voyages of 14 different ships were affected by norovirus in 2012, such that more than three percent of persons got the disease. (Crown Princess and Ruby Princess each were hit twice.) 

The CDC’s Vessel Sanitation Program (VSP) covers about 180 cruise vessels. According to a geographic and economic analysis of the cruise industry by professors Dr. Jean-Paul Rodrigue and Dr. Theo Notteboom, “the standard cruise itinerary is a loop beginning and ending at a hub port and typically lasting seven days…” 

(Of course, some ships offer longer voyages and some offer very short, 3- to 4-day voyages, but, as stated by the professors and as all travel agents know, most ships offer 7-day voyages, on a weekend-to-weekend basis, to maximize predictability and ease scheduling problems.) 

Most vessels are taken out of service for cleaning and maintenance for about one week per year, meaning that each operates about 51 voyages per year. Thus the total number of week-long voyages per year is roughly 9,180 (180 ships times 51 voyages). With that, you can see that your chances of being on a (week-long) voyage where there is an outbreak are about 16 in 9,180, or somewhat more than a tenth of one percent. 

(The year 2012 was not an aberration. There were only 14 outbreaks in 2011 and the same number in 2010.)

Naturally, if you take a longer voyage, you are exposing yourself to a slightly greater risk, since passengers are going ashore and might bring back the virus. In fact, the CDC database for outbreaks over the last three years does show that the average voyage length for an outbreak ship was 12.7 days, longer than the typical voyage. 

Delving deeper into the statistics, in the 16 outbreaks on ships in 2012, on average only 7.2 percent of the passengers on board became ill. Hence the actual chances of taking a voyage, being on an outbreak ship and contracting the disease are only about one one-hundredth of a percent, or one in 10,000.

The chances of your being on a ship that has to reduce its voyage time due to the illness is about the same, about one in 9,000. This is based on the fact that a particular Crown Princess sailing was the only voyage in 2012 that was cut short, in that instance by just two days. 

By the way, your odds of getting injured in a traffic accident over the next year are about 1 in 1,000, according to DisasterCenter.com. So you are 10 times safer once on the ship than driving to it! And all you risk on board is discomfort, while in driving you could be seriously injured or killed. 

Cleanliness = no norovirus?

Are outbreaks caused by poor standards of cleanliness on board? Nope. Consider that the famous Queen Mary 2 scored 100 on the challenging 2012 VSP cleanliness- and-systems inspection, yet soon thereafter the vessel experienced a norovirus outbreak. 

The vessel that scored the lowest in the last two years, the M.S. Columbus 2 of the Hapag-Lloyd line, with an abysmal 69 out of 100 on the VSP on Nov. 15, 2012 (down from a 95 on Sept. 25, 2011), did not report a norovirus outbreak. Vessels generally are scored when they enter US waters, and a passing grade is 86. 

The cause of an outbreak is almost always passengers arriving with the disease and spreading it through touching objects. The cause is not vessel uncleanliness; it’s how many infected passengers walk up the gangway. 

Hand sanitizer or soap? 

Surprisingly, using a hand-sanitizing gel is not the best way to prevent norovirus. The official statement is the “CDC recommends that cruise ship passengers use warm water and soap to wash their hands,” adding, “Washing is always best.” 

The CDC also states, “If water and soap are NOT available… [then] use an ethanol alcohol-based hand sanitizer… [with] at least 62 percent ethanol.” 

Hence the claim that using a gel is the best way to avoid disease is misleading. Gels are good, but the best way, according to the CDC, is good old soap and warm water, just like Mom said. 

According to the CDC, you should wash your hands before eating, smoking, drinking, brushing your teeth or touching your mouth as well as after going to the bathroom, changing diapers, blowing your nose, returning to your cabin, helping a sick person or touching high-contact surfaces. And use a paper towel to open that public restroom door as you leave. 

 

Here are additional techniques that I use to stay norovirus free:

  • I hit elevator buttons with my knuckle, not my fingertip.
  • I don’t touch handrails unless I really need to, as when the ship is rolling. I just hover my hand above the rail, ready to grab.
  • I don’t shake hands with anyone, even the Captain! The new protocol is to touch elbows.
  • I don’t fly to join the ship. In my opinion, airplanes are much more prone to norovirus and other infections than ships. I drive instead (risking that traffic accident!). 

If I must fly, I follow all the hand-washing precautions, especially when using the plane’s toilet. While I have seen cruise ship crew putting in thousands of hours cleaning every surface, I have never once seen an airline crewmember sanitize a plane’s toilet in flight. 

Lessons from the crew

Notice that throughout this analysis, I have been talking about outbreaks among passengers. Crews are more than six times less likely to get infected! Why? Crews are trained to really, really keep their hands clean, while passengers often forget this elementary procedure. 

Crews are also now highly trained to combat norovirus. On a recent Holland America Line cruise that my wife and I took in the Caribbean, our boarding was delayed by several hours while the crew went through a “code red” triple sanitizing of all surfaces on the ship. This was in addition to the normal, once-a-day cleaning of all surfaces. This extra cleaning was required due to illness in the previous load of passengers. 

Standard precautions taken by the cruise line during the first three days of our voyage included installing additional gel dispensers; issuing a letter warning us to wash our hands regularly; closing the hot tubs; not allowing self-service in the buffet, and removing salt and pepper shakers. None of these restrictions was really onerous, and when there were no new infections, most of these restrictions were relaxed. 

If there is a serious attack, the ship will be triple sanitized, with very stringent methods used, including washing all the casino chips, throwing out the pillows and cleaning all the TV remotes, balcony railings, light switches and even Bibles.

Can I get a refund?

But suppose that you go cruising, are incredibly unlucky and are aboard a ship in which the cruise is cut short by a norovirus attack. Can you get a refund? 

It depends on your cruise contract. The small print often will reveal that you have very few rights, but, in practice, most lines are fairly generous and you may get a 50% refund plus a 50% discount on a future voyage. 

If you get norovirus and are quarantined for one to three days in your cabin (a standard precaution) but the cruise is not affected, you are unlikely to get a refund. Sound unreasonable? Well, if you are in a hotel and get a little sick and stay in your room for three days, would you expect the hotel to give you a refund? Not really. 

A broader perspective

I hope I have given you some facts with which to make rational decisions about cruising and norovirus. As is often the case, “scare” stories in the media have completely skewed public perception regarding the real risks in life. 

These are the facts: you have some minor exposure to norovirus every day on land; it is safer to go cruising than to drive, which you do every day; the chances of your getting norovirus on a cruise are minuscule; using common-sense procedures like frequently washing your hands with soap and warm water can reduce your chances even more (at sea and on land), and at sea you have a team of skilled and motivated people cleaning all the surfaces around you all the time. (Do you have that service at your house?) 

Perhaps we need to acknowledge that all of life is a bit of a crap shoot. Even if you hide in your closet forever, you could be hit by a meteor! So get out there and have some fun. My rational decision is to stop worrying and go cruising.