An outbreak of highly-contagious norovirus has made more than 70 people sick on a Royal Caribbean International cruise ship. 

According to the Centers for Disease Control and Prevention, at least 71 passengers and one crew member have been confirmed to have contracted the virus responsible for causing diarrhea and vomiting, among other symptoms.

Stool tests from the unwell passengers confirmed infection with norovirus. The Royal Caribbean Serenade of the Seas, where the outbreak occurred, holds a total of 1,874 passengers and 883 crew members.

This implies that just under four percent of passengers have been affected. The CDC categorizes a cruise ship outbreak as occurring when at least three percent of passengers on a vessel carrying more than 100 fall ill.

The Serenade of the Seas set sail from San Diego on September 19. It visited Mexico, Costa Rica, Panama, and Colombia, and is expected to arrive in Miami on October 2.

The outbreak notification reached the CDC on September 28 via its vessel sanitation program, which keeps track of gastrointestinal illness outbreaks on cruise ships scheduled to arrive at US ports.

Royal Carribean is isolating sick passengers, collecting stool samples for testing and ramping up cleaning procedures according to the CDC. 

Royal Caribbean issued a statement saying: ‘The health and safety of our guests, crew, and the communities we visit are our top priority. To ensure an environment that supports the highest standards of health and safety on our ships, we implement thorough cleaning procedures, many of which go well beyond public health guidelines.’

A total of 1,874 passengers and 883 crew are aboard the Royal Caribbean Serenade of the Seas ship (pictured) where the norovirus outbreak took place

So far this year, the CDC has recorded 19 outbreaks of gastrointestinal illnesses on cruiseships, 14 of which were caused by norovirus. The virus also caused 15 out of 18 outbreaks on cruiseships last year, and 13 out of 14 the year before. 

The 13 outbreaks of norovirus on cruiseships in 2023 was the highest number seen in more than 10 years before that, and since then the cases have only gone up. This seems to indicate an upward trend, but experts are not sure. 

‘While the number of recent cruise ship outbreaks has been higher than in years prior to the pandemic, we do not yet know if this represents a new trend,’ the CDC told USA Today.

‘However, CDC data show a newly dominant strain is currently associated with reported norovirus outbreaks on land. Ships typically follow the pattern of land-based outbreaks, which are higher this norovirus season.’

The current norovirus outbreak comes just two months after a similar outbreak on another Royal Carribean cruise in July. 

In that case, 140 passengers fell ill on the Navigator of the Seas, experiencing vomiting, diarrhea and stomach cramps. 

In February, yet another Royal Carribean cruise ship experienced a norovirus outbreak which ultimately infected 160 passengers on the Radiance of the Seas. Several other cruiseliners have also reported outbreaks this year. 

Early reviews have indicated that the outbreaks may be caused in part by an overreliance on the use of hand sanitizer on cruise ships. Soap and water are more effective to combat the virus, according to the CDC. 

Norovirus is highly contagious, and a little less than four percent of passengers on the cruiseshup are confirmed to have been infected

Norovirus is extremely contagious, and it can spread easily and make anyone sick. The virus is transmitted most easily in confined spaces such as cruise ships, but also places like schools, nursing homes and hospitals. 

The virus induces nausea, diarrhea, vomiting, abdominal pain or cramping, as well as less common symptons such as muscle aches, headaches and low fever. 

The symptoms usually begin 12 to 48 hours after infection, and they typically last one to three days, but people can continue to spread the virus after symptoms have subsided. 

It takes a small number of norovirus particles to make a person sick, and the disease can be contracted simply by touching the same surface that an infected person did. 

Norovirus can also spread through shared use of eating utensils, eating or drinking contaminated food or beverages and having direct contact with someone who is sick. 

On average, the virus makes 19 million to 21 million people in the US sick each year, according to the CDC. Most recover, but around 900 people die from the illness each year, usually among those 65 years old and over. 

There is no specific treatment or cure for norovirus, but the CDC recommends drinking plenty of water or drinks high in electrolytes. It recommends avoiding caffiene or alcohol, as those can cause dehydration. 

The best ways to avoid and limit the spread of norovirus is by washing your hands often, self isolating when you feel symptoms and avoiding others who are sick. 

The CDC also recommends regularly disinfecting surfaces and washing laundry that might be contaminated if there is an outbreak.