Two Steamship Authority employees have now tested positive for Covid-19 in as many days — including one who worked a Vineyard route — prompting the boat line to cancel trips and make other schedule changes beginning this week, as well as institute mass testing among employees and temporarily close reservations.

In a press release that went out after midnight Saturday, the SSA announced that an employee who had recently worked on the M/V Woods Hole and the M/V Governor tested positive for the virus that day. One day earlier the boat line had announced that an employee who worked on the ferry Woods Hole had tested positive for the virus.

The hybrid freight-car ferry Woods Hole has been servicing the Nantucket route most recently. The Governor is a 42-vehicle freight vessel that plies the Vineyard route in summer and fall.

SSA spokesman Sean Driscoll said in the release that the boat line did not know if the two cases were related, but he expressed confidence that the employee did not have extended interactions with passengers.

But due to the proximity of the two positive tests, the SSA said it would be cancelling trips and taking the ferries out of service on Sunday to limit potential spread of the virus. The Woods Hole was removed from service and berthed in Fairhaven, with the boat line cancelling its first trip of the morning. The SSA also cancelled the Governor’s first three trips of the morning Sunday.

Both ferries were due to be cleaned by outside vendors, the boat line said, as a supplement to all regular daily cleanings that the vessels undergo.

In a followup press release late Sunday afternoon, the SSA announced a complicated array of further schedule changes for Monday and Tuesday due to reduced manning capabilities on ferries. The release also said the boat line had identified 23 employees who may have had contact with the two employees who have tested postive for the virus, and had arranged for them to be tested at Cape Cod Hospital.

After those results are known, the SSA will make further determinations about schedules for the remainder of the week, the release said.

The current changes include moving the freight ferry Sankaty to the Nantucket route, and using the Woods Hole on the Vineyard route for Monday and Tuesday. All told, the changes will include the cancellation of every Sankaty trip on the Vineyard route for Monday and Tuesday, as well as the cancellation of the Governor’s last three trips of the day Tuesday.

Cancelled Tuesday trips are as follows: trips leaving Woods Hole at 2:50 p.m., 5:20 p.m. and 7:45 p.m. and trips leaving Vineyard Haven at 4:05 p.m., 6:30 p.m. and 8:45 p.m.

The boat line also announced later Sunday that it had temporarily frozen advance vehicle reservations through Tuesday, Sept. 8 in order to allow time to make further schedule changes if necessary. All advance reservations were due to be available again by mid-day Monday, the release also said. An announcement will be made when customers can book or change their trips in all three ways: online, by calling the reservation office or at a terminal.

The employee who tested positive Saturday last worked on the Governor on Saturday, August 29, the SSA said. Because the Governor is not listed in schedules online, it is unclear what trip ended the employee’s shift.

The SSA is not disclosing the name or position of the employees in order to protect their confidentiality, the release said.

The two employees who have tested positive over the past two days mark at least the third and fourth SSA employees to test positive for the virus since the pandemic began.

SSA employees and passengers are required to wear face coverings on the boat, and all employees must undergo a health screening before beginning their watch.

Boat line general manager Bob Davis wished both employees a quick recovery, and defended the temporary operating changes.

“Our employees have done an extraordinary job following our Covid-19 protocols thus far, for which I am grateful. However, given the proximity of these two test results and the number of crew members who have potentially been exposed, these temporary operational changes are the best way to ensure the health and safety of everyone,” he said in the release.