Cruise ships and norovirus: fact or myth

So far this year, three cruise ships had significant norovirus outbreaks, infecting 1,023 passengers and crew. That may seem extraordinarily high to many. However, while it’s of little solace to passengers and crew who were sick, 94.1 percent of the passengers and crew on the three cruises remained well.

In recent discussions with travelers about cruise ships and norovirus, I’ve found there is much misinformation about the subject. More than a few people, for example, believe that cruise ships, especially their kitchens, are filthy and poorly maintained, giant incubators for norovirus and that cruisers are lucky to finish a cruise without getting sick.

Here are some facts and myths to consider about cruise ships and norovirus.

• Fact or Myth: You’re more likely to become infected by norovirus on a cruise ship than anywhere else.

Myth: Each year in the US, norovirus infects about 20 million people (about 6.3 percent of the population). By contrast, reported cruise ship norovirus outbreaks accounted for fewer than 2,000 cases last year among the 20 million who sailed (about 0.01 percent of cruisers).

According to the Centers for Disease Control (CDC), Norovirus outbreaks are most common in healthcare facilities, including nursing homes and hospitals. More than 50 percent of all norovirus outbreaks in the US occur in long-term care facilities. Many outbreaks also occur in schools, restaurants, summer camps, etc.

• Fact or Myth: Cruising is unsafe because a high percentage of cruisers contract norovirus.

Myth: In all of 2013, there were nine outbreaks of norovirus on major cruise ship lines, according to the CDC, during which about 1,500 passengers and crew contracted norovirus, out of a total of almost 27,000 (5.6 percent) passengers and crew on board. Even accounting for others infected with norovirus on ships without “outbreaks,” that’s a tiny fraction of the 20 million passengers who cruised in 2013.

• Fact or Myth: Poor cruise ship maintenance and unsanitary conditions are the cause of most norovirus outbreaks on ships.

Myth: The CDC inspects many cruise ships, sometimes more than once per year, as part of its Vessel Sanitation Program. Ships fail their inspections if they score 85 or below on a 100 point scale. In 2013, just fifteen ships failed an inspection, and thirty-six scored a perfect 100. Each ship corrected identified problems.

All ships are required to correct all violations. Some critical violations must be corrected immediately. Each ship must submit a “Corrective Action Statement” that details how the violations were corrected.

It’s in the cruise lines’ best interest to maintain their ships well and keep them clean and sanitary. Norovirus outbreaks hurt cruise lines’ bottom lines.

The last CDC inspection scores for the three ships with norovirus outbreaks this year are: Caribbean Princess — 98, Explorer of the Seas — 98, and Norwegian Star — 94. It would be a stretch to think that the outbreaks on these ships were caused by unsanitary conditions or poor maintenance.

• Fact or Myth: Crew members generally bring norovirus on board their ships.

Myth: While it’s generally impossible to trace exactly who or what was responsible for a norovirus outbreak on board any ship, we can do a statistical analysis which can give us some insight.

In 2013, for example, based on CDC statistics describing the nine norovirus outbreaks that year, passengers were approximately 6.4 times more likely, on average, to contract the virus than the crew. Considering living conditions for the crew and passengers, and the close proximity at which crew members work and eat, it’s possible to infer that it’s much more likely a passenger brought the virus aboard these ships than a crew member.

• Fact or Myth: You can get norovirus merely by touching a cruise ship’s stateroom door handle.

Fact: Norovirus is very contagious. You can get norovirus by touching or being touched by an infected person, from contaminated food or water, or by touching contaminated surfaces. Touching surfaces or objects, such as a door handle contaminated with norovirus, then putting your fingers in your mouth can cause you to become infected with the virus.

• Fact or Myth: There is a vaccine which can prevent norovirus and drugs to treat it.

Myth: As clearly stated by the CDC, there is no norovirus vaccine, nor drugs which specifically treat victims of the virus. Norovirus infection cannot be treated with antibiotics because it is a viral infection.

Norovirus treatment mostly involves replacing fluids lost from vomiting and diarrhea which result from the disease. Dehydration can lead to serious problems, and severe dehydration may require hospitalization for treatment via intravenous fluids.

• Fact or Myth: There are several steps anyone, including cruisers, can take to prevent becoming infected with norovirus.

Fact: The most important norovirus preventative is proper hand hygiene.

One’s hands should be carefully washed with soap and water:

— after using a toilet, urinal, or changing diapers and before eating, drinking, preparing or handling food.

While hand sanitizers aren’t as effective as proper hand washing, when you can’t wash with soap and water, use the sanitizers.

Norovirus will be in your stool before you feel sick and for two weeks or more after you feel fine. It’s important to practice proper hand hygiene even after you are feeling well.

Any clothes or linens which may be contaminated (vomit, stool, etc.) should be thoroughly laundered, even when on a cruise, before reuse.

When you’re sick, don’t prepare food or care for others who are sick. On a cruise ship, you might be stuck in the same stateroom with a spouse, partner, family member or friend who is sick. Don’t share their bed or any linens. Don’t eat any food they might have contacted.

All contaminated surfaces should be cleaned with a chlorine bleach solution.