Joining four other Vineyard towns, the Chilmark board of health voted unanimously Wednesday to adopt an indoor mask mandate for all public spaces and all private spaces open to the public, citing the rapid spread of the Delta variant.

The Martha’s Vineyard Hospital is seeing its largest numbers of Covid and non-Covid related patients since the pandemic began, testing emergency room capacity as cases spike on-Island during the peak of summer.

As rising sea levels pose real threats to coastal communities around the commonwealth, state grants were announced this week for 16 towns, including three in Dukes County.

The Edgartown, Oak Bluffs and Tisbury boards of health voted unanimously to institute a mask mandate for indoor public spaces during a rare emergency, joint meeting Tuesday morning, changing course again as cases climb.

All three down-Island towns are scheduled to hold a joint emergency board of health meeting Tuesday to discuss an indoor mask mandate, as Covid cases continue to double by the week in August.