One side effect of cruise covid rules: Norovirus has plummeted

One apparent result of the measures cruise lines have taken against covid-19: Outbreaks of gastrointestinal illness have been far lower than in pre-pandemic years.

One side effect of cruise covid rules Norovirus has plummeted

So far this year, cruise lines have reported two outbreaks of vomiting and diarrhea to the Centers for Disease Control and Prevention that affected 3 percent or more of passengers or crew. That’s part of the outbreak threshold that determines whether the agency discloses episodes to the public. Ships must have a foreign itinerary with U.S. ports and need to be carrying at least 100 people. The two outbreaks, affecting a total of 113 people, took place on a Carnival Cruise Line ship in late May and a luxury Seabourn voyage from late April through May. Norovirus was the cause of the Carnival illnesses, the CDC said on its site dedicated to updates about gastrointestinal illness on cruise ships; the Seabourn cause was unknown. Last year, when cruise lines gradually started sailing again after a pause of more than a year, only one outbreak was reported. That one, caused by Vibrio and E. coli bacteria, hit 120 people on a Viking Ocean ship. Operators didn’t report any cases in 2020; the industry voluntary shut down in March of that year. Three outbreaks in the course of more than a year is much lower than pre-pandemic numbers. In an email, the CDC said the decrease in the number of acute gastroenteritis outbreaks could “most likely be attributed” to the combination of fewer passengers on ships during that time and “nonpharmaceutical interventions used by cruise ships to mitigate COVID-19 transmission, such as increased cleaning and disinfection, increase in the number of hand sanitizer stations, crew served buffets, and physical distancing.”

Norovirus cases on land are also lower than normal. According to the CDC, the number of outbreaks reported by states during the 2021-2022 seasonal year (August to July) is lower than the range reported during the same time over the eight previous years. The CDC’s Vessel Sanitation Program has worked with the industry to monitor gastrointestinal illness since 1975, after “an excessive number” of outbreaks. While incidence rates of stomach illness on cruise ships dropped between 2006 and 2019, according to the CDC, pre-pandemic numbers were closer to 10 or 11 outbreaks a year. 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-enclosed environments such as cruise ships” — was found to be a cause in 22 of those episodes. That’s a small fraction of the number of cruise passengers during those years: More than 13.7 million cruise passengers took cruises from U.S. ports in 2019, according to the Cruise Lines International Association.

Source: this news is originally published by washingtonpost