Bucking state and national trends, Dukes County has both the highest Covid-19 positive rate and the highest Covid-19 vaccination rate in the commonwealth, with health agents reporting a major jump in cases last week, as the Island continues to lead the way in the vaccination process.

The seemingly incongruous trends were made available Monday in state and local case and vaccination updates. While health agents reported 55 new positive Covid-19 tests last week, reflecting a 22-case jump from the prior week, state vaccine numbers showed that more than 81 per cent of Dukes County had received a first-dose vaccine shot, and that 63 per cent of the county was fully vaccinated.

Both reflect the highest rates in the state, with Nantucket County trailing close behind. Demographic information is based on a 2019 census update.

In Monday’s expanded case update, health agents reported that 41 of the 55 new positive cases were symptomatic, 10 were asymptomatic and four were unknown. Health agents also officially reported a three-case cluster connected to the Cardboard Box restaurant in Oak Bluffs. All three positive cases were staff members, according to Oak Bluffs health agent Meegan Lancaster.

An unusually high proportion of last week’s 55 cases came among younger members of the Island population, according to the case update, with 13 people in their 30s testing positive, 19 in their 20s, and 14 people under the age of 20, reflecting more than 85 per cent of the positive tests. The 34 per cent of people in their 20s who tested positive is nearly double the normal positivity rate of people in their 20s.

Cumulatively, there have been 1,473 Island residents who have tested positive for the virus since the pandemic began last spring. While case numbers stayed relatively low until the fall of 2020, the Island has since seen significant case fluctuations, with a recent spike in late March. Although cases declined throughout April and early May, they remained steady last week before this week’s substantial jump.

There are currently 55 active cases on the Island, the most since April.

Hospital officials have been testing for case variants on the Island, detecting the more contagious B.1.1.7 variant earlier this spring. Testing for the P.1 continues, according to hospital officials, with preliminary samples coming back negative.

But just as cases have refused to relent, Island vaccine clinics continue to lead the way throughout the state.

According to online hospital updates, 12,873 people have received a first-dose vaccine shot and 10,572 have received a second-dose shot. A mobile vaccination bus that came to the Island last week through a federal partnership with Island Health Care also provided hundreds of vaccines to Island residents.

In an email, IHC spokesman Mary Breslauer said the mobile clinic provided 484 total shots, including 107 on Saturday, 59 on Sunday, 103 on Monday, 112 on Tuesday and 103 on Wednesday.

The clinic made a variety of stops on the Island, including Steamship Authority terminals, Brazilian churches and the regional high school, offering both the Pfizer and Johnson & Johnson vaccines.

In a separate email, hospital spokesman Marissa Lefebvre said 231 children ages 12 to 15 had received a vaccine at the hospital as of Friday at 8 a.m., and that vaccine appointments would be available on Tuesdays, Thursdays and Saturdays from now on.

“Overall, we have done a lot of outreach in coordination with various community organizations. Currently, we’re focused on reaching parents of the 12-15 age group and businesses as more open and employees go back to work,” Ms. Lefebvre wrote.

The 63 per cent of people who have received a second-dose shot is the highest rate in the state by five percentage points. Outside the Cape and Islands, no state county has more than 50 per cent of its population fully vaccinated.

Broken down by age group, more than 95 per cent of people in their 30s, 40s, 60s, and over the age of 70 have received a first-dose shot, and 92 per cent of people in their 50s have received a first-dose shot.

Island residents in their 20s are lagging behind, with only 75 per cent of the demographic having received a first-dose shot, according to state data.