CDC Says Coronavirus Traces Lasted 17 Days On Cruise Ship, But No Evidence Of Transmission Risk

CDC Says Coronavirus Traces Lasted 17 Days On Cruise Ship, But No Evidence Of Transmission Risk
Photo: Cameron Spencer, Getty Images

Traces of the novel SARS-CoV-2 virus can last longer on some surfaces than previously detected by health authorities, according to a Centres for Disease Control and Prevention report released on Monday.

Health officials were able to detect viral RNA on the Diamond Princess cruise ship, which had a major coronavirus outbreak earlier this year, up to 17 days after an onboard quarantine of passengers and crew concluded. However, the CDC emphasised that it had no evidence that the remaining traces of the virus posed a risk of new infections.

“SARS-CoV-2 RNA was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated on the Diamond Princess but before disinfection procedures had been conducted,” the CDC wrote in its Morbidity and Mortality Weekly Report, citing research conducted by the National Institute of Allergy and Infectious Diseases. “… Although these data cannot be used to determine whether transmission occurred from contaminated surfaces, further study of fomite transmission of SARS-CoV-2 aboard cruise ships is warranted.”

The CDC reiterated that the virus and the disease it causes, covid-19, “poses a risk for rapid spread of disease [on cruise ships], causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread.”

Again, it’s not clear that means virus-contaminated surfaces still posed an infection risk after 17 days, and the cramped, indoors quarantine conditions on the Diamond Princess likely contributed the detection of viral traces. Previous research published in the New England Journal of Medicine has only determined that the coronavirus can last up to three days on plastic and stainless steel, and several hours in the air, where the risk of infection is highest.

The samples were also found in rooms that had not been cleaned—which should be a reminder to stick to guidelines issued by health authorities, like regularly disinfecting surfaces, washing hands for at least 20 seconds, keeping hands away from faces, and continuing with social distancing. All available evidence indicates that common household cleaners and disinfectants are more than capable of destroying the virus, as long as they’re used properly.

At least 712 (19.2 per cent) of the 3,711 passengers and crew on the Diamond Princess had positive test results for SARS-CoV-2, according to the CDC; around 331 of these individuals were asymptomatic at the time of the test. The CDC has previously said that food workers on the Diamond Princess were particularly vulnerable the spread of the coronavirus on the vessel, as the staff cafeteria was the primary place where workers congregated. Infectious disease specialist Kentaro Iwata of Kobe University Hospital described onboard efforts to contain the virus as “completely inadequate,” with the Guardian reporting that crew saw little effective effort to separate exposed or sick individuals from uninfected ones.

As of Monday evening, the New York Times tracker lists at least 43,024 confirmed coronavirus diagnoses, with 536 deaths, spread over all 50 states, three U.S. territories, and DC. New York has been particularly hard hit, with at least 20,875 confirmed cases and 157 deaths. Data from China shows the virus causes only mild symptoms in the vast majority (over 80 per cent) of infected individuals, though research has shown people who are asymptomatic or not yet experiencing symptoms are fuelling its spread across the globe.