Just days after opening its border to the U.S. mainland, American Samoa has reported its first case of Covid-19.

All inbound flights to Pago Pago have been suspended until further notice.

American Samoa began twice-monthly flights between capital Pago Pago and Honolulu on Monday, following the implementation of a set of regulations for incoming travelers that included mandatory vaccination. The territory, which has been closed since March last year, had no cases in country until now.

The single, asymptomatic case is a female traveler who arrived on the first flight from Hawaii. She was detected in a group of 43 people quarantining at Sadies by the Sea, in Utulei, and was transported to a separate quarantine facility, according to a Department of Health statement. The infected person was fully vaccinated and appeared not to be a historical case.

All those who made contact with the case have been moved into quarantine, reported local news outlet Talanei.

“The discovery of this positive case during quarantine highlights the importance of why our process is critical to prevent the spread of COVID-19. It further highlights the importance of maintaining our current quarantine protocols,” said Gov. Lemanu Peleti Mauga in a statement.

American Samoa has implemented several protocols for travelers, including a mandatory vaccination, three negative Covid-19 tests, and mandatory 10-day quarantine upon arrival. It had scheduled flights until Dec. 20 with Hawaiian Airlines before the positive case.

Talanei also reported that flights chartered from Apia, Samoa, for workers at its StarKist tuna cannery had been cancelled. It has employed 200 Samoans to work at the cannery, and 50 remain in Apia.

Almost half of American Samoa’s population is vaccinated, though Lt. Gov. Talauega Eleasalo V. Ale has “resisted mandating anything to our people.”

A $100 per dose incentive is being given to residents until Oct. 15.