An obvious result of the measures cruise lines have taken against Covid-19 – outbreaks of gastrointestinal illness have been far fewer than in the years leading up to the pandemic.
This year, cruise lines have reported two outbreaks of vomiting and diarrhea to the US Centers for Disease Control and Prevention (CDC), affecting at least 3 percent of passengers or crew.
That’s part of the breakout threshold, which determines whether the agency will release episodes to the public. Ships must have a foreign route with US ports and carry at least 100 people.
The two outbreaks, which affected a total of 113 people, occurred on a Carnival Cruise Line ship in late May and on a Seabourn luxury cruise from late April to May.
Norovirus is the cause of carnival sickness, the CDC said on its website, which deals with updates on cruise ship gastrointestinal illnesses; The Seabourn cause was unknown.
When cruise lines gradually started sailing again last year after a break of more than a year, only one outbreak was reported. This, caused by Vibrio and E. coli bacteria, hit 120 people on a Viking Ocean ship.
Operators reported no cases in 2020; The branch was voluntarily shut down in March of this year.
Three outbreaks over the course of more than a year is much fewer than before the pandemic. In an email, the CDC said the decline in the number of acute gastroenteritis outbreaks was “most likely” due to the combination of fewer passengers on ships during this time and “non-pharmaceutical interventions being undertaken by cruise lines to curb transmission of Covid-19.” such as increased cleaning and disinfection, increasing the number of hand sanitizer stations, crew-served buffets, and physical distancing.
Norovirus cases are also lower than normal on land. According to the CDC, the number of state-reported outbreaks in the 2021-2022 season year (August through July) is less than the range reported at the same time in the previous eight years.
The CDC’s Vessel Sanitation Program has worked with industry since 1975 to monitor gastrointestinal illness after “an excessive number” of outbreaks.
While incidence rates of gastric disease on cruise ships fell between 2006 and 2019, pre-pandemic numbers were closer to 10 or 11 outbreaks per year, according to the CDC. Between 2017 and 2019, cruise lines reported a total of 32 outbreaks that sickened 3,359 people.
Norovirus — which the CDC says “can spread quickly in closed and semi-closed environments like cruise ships” — was found to be the cause in 22 of those episodes.
That’s a small fraction of the number of cruise passengers in those years — more than 13.7 million cruise passengers took cruises out of U.S. ports in 2019, according to the Cruise Lines International Association.
William Schaffner, a professor of infectious diseases at Vanderbilt University School of Medicine in Nashville, said the lower number of cruises as the industry restarts and lower passenger concentration — at least on many lines — are likely factors behind the lower number of outbreaks. But he said the precautions taken against Covid-19 were “undoubtedly useful” in combating the spread of norovirus as well.
“The stricter we are with all these hygiene measures, the more other infectious agents will be transmitted,” he said.
Norovirus, he said, is “extremely” contagious. Schaffner praised cruise lines for their disinfection practices even before the coronavirus emerged.
“Before this happened, the cruise industry, under the guidance of the CDC, had a lot of infection control activities in place that they implemented really rigorously,” he said.
Cruise lines have touted improved cleaning and hygiene protocols since the pandemic began. Royal Caribbean International, for example, says on its website that while hand sanitizer stations have always been on board, the line has increased the number by 75.
“And we’re placing them wherever you’re most likely to use them, near elevators and at exits and entrances to all venues, as well as anywhere on board where there aren’t hand washing stations or toilet sinks in close proximity,” according to the site says.
The company said it has improved its cleaning protocols, noting that high-traffic areas such as elevators, stairs, escalators and boardwalks are cleaned every two hours and gangway rails are cleaned every 20 to 30 minutes when the surrounding area is busy.
Norwegian Cruise Line said it has implemented “comprehensive enhanced cleaning and hygiene protocols” and has had a dedicated health officer on all ships who “oversees the daily hygiene and cleanliness of all public areas and accommodation”.
At least temporarily, some cruise lines have ditched self-service buffets to let staff serve passengers at the aid stations — although the old style has largely returned, according to cruise news site Cruise Critic.
The CDC says norovirus is spread through direct contact or sharing food or utensils with someone who is infected. Outbreaks can also be caused by contaminated food, water, or surfaces. Common facilities include health facilities, restaurants, schools or childcare facilities, and cruise ships, the agency says, though it notes that ships account for just 1 percent of all norovirus outbreaks.
According to the CDC, the virus can persist on surfaces for days or weeks.
“Norovirus can be particularly difficult to control on cruise ships because of the cramped living quarters, common dining areas, and rapid passenger turnover,” the CDC says on its website.
“When the ship docks, norovirus can be brought on board in contaminated food or water, or by passengers who have been infected while on land.”
https://www.independent.ie/life/travel/cruise/one-side-effect-of-cruise-ship-covid-rules-norovirus-has-plummeted-41930473.html A side effect of the Covid rules for cruise lines? Norovirus has declined sharply