After years of decline, norovirus outbreaks surge on cruise ships

After years of decline, norovirus outbreaks surge on cruise ships


Millions of Americans travel to cruise ships for vacation from Miami, New York or Seattle. When it comes to their health, however, things are not always as smooth.

According to the US Centers for Disease Control and Prevention, there have been 13 norovirus outbreaks on cruises in this year. This is the highest number norovirus outbreaks ever recorded on cruises, and there's still almost half the year to go.

On June 20, a Viking Cruises ship from Iceland docked at New York City. Around 13% of passengers as well as several crew members became ill while on board.

A Viking representative told CNN that 'we believe the gastrointestinal disease originated from a shoreside Iceland restaurant where a group dined in their spare time'.

"An extremely contagious virus"

The norovirus virus is highly contagious and causes stomach and intestinal inflammation, also known as acute gastroenteritis. According to the CDC, norovirus, also known as a'stomach virus,' is the leading cause of nausea and vomiting, diarrhea, and stomach pain.

Norovirus can be contracted by accidentally ingesting microscopic feces and vomit particles. This could occur when a person comes into contact with an infected person, consumes contaminated water or food, or touches contaminated surfaces. Although the symptoms last for a few days at most, they can persist up to two weeks.

William Schaffner is a professor at Vanderbilt University who specializes in infectious diseases. He said, "This virus is extraordinarily contagious." It only takes a few viral particles for an exposed person to become infected. This means that it doesn't require a huge dose, but only a small amount.

Most people recover completely without any treatment, even though there is no medication to treat this illness. Standard treatment for symptoms is to use hydration therapy to replace fluids lost through vomiting or diarrhea.

Schaffner advises cruise passengers to take extra precautions in order to avoid the spread of norovirus. They should wash their hands with warm soapy water and thoroughly. Hand sanitizers and antiseptic gels do not work against norovirus.

Jeffrey Fisher, associate professor of nutrition at Central Michigan University, said that we have all washed our hands since we were children. But there have been many studies that show we don't wash our hands as well as we should or as often. We want to review the best hand-washing practices.

Surging cases

Experts believe the soaring number of cruise passengers and a record demand for cruises could be to blame.

The CDC's Vessel Sanitation Program reported that the number of norovirus outbreaks aboard cruise ships docked at U.S. port cities had been steadily declining since 2015. The overall rates of gastroenteritis in cruise ships docked at U.S. ports also declined from 2006 to 2019.

The CDC issued a travel warning in response to the Covid-19 outbreak, citing safety concerns. CDC spokesperson Kathleen Conley stated that cruise ship travel was limited and that outbreaks were rare as the number passengers decreased.

The program has recorded no norovirus cases in 2020 or 2021. This is likely due to the limited cruises and the updated sanitation protocols during the Covid-19 pandemic.

The agency removed the risk warning for cruise travel in March 2022, and since then, passengers have been returning to their cruises at a record rate.

This year, 31.5 million passengers are expected to travel around the world. This is a significant increase over pre-pandemic levels. It also creates high-density areas that are conducive for infection.

The CDC will release information on outbreaks of a disease when there are more than 100 passengers travelling between three to 21 days and if over 3% passengers and crew members report symptoms.

These conditions were met 13 times in 2018, up from just two times in 2022.

Royal Caribbean has had the highest number of norovirus outbreaks of any cruise line this year.

Royal Caribbean International's spokesperson told CNN via email that the health and safety our guests, our crew, and the communities we visit is our number one priority. To maintain the highest level of health aboard our ships, we use rigorous safety and cleansing procedures. Many go beyond public health guidelines.

Perfect storm

Norovirus outbreaks on cruise ships are rare compared to the general population. According to the CDC it infects between 19 and 21 million Americans each year. This compares to a few hundred cases on cruise ships.

Norovirus can spread in crowded areas where small particles can float around. Schaffner believes cruises are the ideal environment to cause norovirus outbreaks. He said that a large group of people living and eating close together can be a breeding ground.

He said: "They are an enclosed population. A very large, tightly packed population, which is together for long periods, and often in very tight quarters." There are many chances for people to come into contact with each other, making it easy for the virus to spread.

He said that norovirus symptoms could also appear suddenly. The passenger may be on their way to the cabin or at an event when they suddenly start vomiting. This aerosolized vomit can spread disease to people who are nearby.

Schaffner explained, 'You've got this highly transmittable virus introduced into a cruise ship environment that is designed to spread a communicable illness quickly.

Dehydration can occur even though symptoms such as diarrhea and vomiting usually disappear in a couple of days. Schaffner warns that rapid fluid loss could lead to more serious illnesses for older passengers, who make up a large proportion of cruise clients. Dehydration can affect treatment plans for people with diabetes.

Fisher believes that a large part of the problem is due to a lack of knowledge about the virus in the public. People are letting their guard down as the Covid-19 epidemic appears to be winding down.

He said: 'I don't think many people understand norovirus or how to start protecting themselves.' They're not following the precautions and good protective behaviors that they learned during the pandemic.

Schaffner suspects also that those who feel ill prior to boarding are more likely to embark. He suggested that many people, eager to get away after a pandemic delay of 2 1/2 years, could bring norovirus along with them.

He advised passengers to postpone their trips if they are not feeling well. Try to limit exposure on the front end and take another cruise one month later.

The CDC Vessel Sanitation Program not only monitors disease outbreaks aboard, but also conducts unannounced regular inspections and provides training to cruise ship staff about public health.

The CDC recommends that passengers wash their hands thoroughly, avoid contaminated foods, and keep their fingers away from their mouths. Schaffner, as well as the CDC, recommend that if a passenger becomes ill they stay in their cabin and notify the medical team on board immediately.

Schaffner advised: 'Let the professionals take care of you.' Don't spread the virus by going out.