01 USS San Diego FILE
Washington CNN  — 

About a dozen sailors and Marines onboard the USS San Diego tested positive for Covid-19 while the ship was deployed to the Middle East, the Navy said in a statement Thursday. 

The amphibious transport ship is pierside in Bahrain, and all positive cases have been isolated onboard. The ship remains in a Covid-restricted bubble.

In addition, the USS Philippine Sea has several people “under investigation” for possible Covid-19, according to a statement from US 5th Fleet. The guided missile cruiser is expected to pull into port for further testing of anyone who may have been exposed. The port location will not be disclosed, the 5th Fleet said.

Confined spaces are vulnerable to outbreaks of the virus, as seen last year on the USS Theodore Roosevelt aircraft carrier, when nearly 20% of the ship’s crew tested positive for Covid-19. Within weeks of the outbreak, more than 1,000 members of the Roosevelt’s 4,900-member crew tested positive, prompting the Navy to evacuate most of the crew to Guam.

CNN’s Rachel Janfaza contributed to this report.