The CDC is reporting that they found the coronavirus remained present on at least two cruise ships 17-days after passengers were first evacuated from them.

The discovery was announced Monday during continued study of the virus in hopes of understanding it.

The new data shows that the virus has the ability to stay on surfaces longer than the 14-days originally thought.

The study was conducted on both the Princess Diamond Cruise ship in Japan and the Grand Princess ship in California.

Researchers say after the virus was detected on both ships, passengers and crew members were quarantined for the recommended 14-days before being released. Researchers found that the virus “was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after the cabins were vacated on the Princess Diamond, but before disinfection procedures had been conducted.”

Another study is being conducted to determine how the virus was able to spread across voyages.  As of March 17th at least 25 cruise ships have had passengers and or crew members test positive for the virus either during or after the cruise ended.

For example, on February 4th, 3,700 people were quarantined on the Diamond Princess after a previous passenger tested positive for the virus when he returned home to Hong Kong. 800 passengers came down with the illness and 9 people died from it.

On the Grand Princess, two people tested positive for the virus which eventually led to 78 more cases across multiple voyages.

One finding is that 46.5% of people who contract the virus are asymptomatic, meaning they have no symptoms at all. This could explain the “high attack rate.”