COVID-19 testing, which had dwindled over the past several months, has risen sharply in recent weeks as delta variant cases surge across Massachusetts.

Testing for the virus slowed down as more people were vaccinated, and concerns about exposure declined. But the spread of the delta variant in June and July, including a cluster of vaccinated people in Provincetown, has left many wondering if a simple cough could be COVID-19. State testing numbers show the number of tests administered statewide nearly doubled from the first Wednesday in July to the first Wednesday in August.

Boston Health and Human Services Chief Marty Martinez said he’s seen a boost of about 25% over the past couple of weeks — rising to about 2,200 people being tested a day — and he’s not finding it surprising given the concerns over the delta variant

“We’ve seen an increase, even in one of the sites we run ourselves. Through a contract we test in Jamaica Plain and have seen an increase up to about 1,600-1,700 tests per week,” he said in a Friday interview.

Martinez said the city is talking with community centers about adding testing days, and is focusing its strategy around the upcoming school year and fall cold-and-flu season. Schools will have pooled testing again for staff and students in partnership with the state.

“With the delta variant spreading and more people getting infected, we anticipate that we’ll need to make sure there’s enough capacity if not more capacity to get tested, and that’s some of the legwork we’re doing now,” he said.

Martinez was at a site in Jamaica Plain last week that has up to 8 stations available for testing. Five stations were open to meet the demand.

He said community groups are asking the city to remind the public to get tested. “Regardless of vax status you should be getting tested if you have COVID symptoms,” he said.

That same urgency is being replicated around the state. Worcester County’s COVID-19 cases are up over 66%, with 432 new cases and nine deaths in the latest week of data, up from 260 cases the week before.

“In the last three weeks we’ve seen an increase of people wanting to get tested because it seems like the delta variant is here now,” said Michelle Muller, a family nurse practitioner and COVID-19 Testing and Vaccine Manager for UMass Memorial Health.

The organization has been running a testing site at the Mercantile Center in Worcester since 2020, with testing numbers peaking in January 2021 with 1,500 tests a day with three available days per week. That number dropped to 120 people a day in June.

“We started seeing the numbers start to go down as the vaccine started coming out,” said Muller.

That shifted with the delta variant, and the site is now testing around 300 people daily.

The hospital network is extending its Thursday testing hours beginning next week, and is considering adding Tuesday as a test day. Muller said UMass Memorial is putting more resources back into testing in conjunction with its vaccination program. They rehired five people to conduct testing and are considering opening a Marlborough site.

“We’ve had groups reach out to us requesting our schedule for the testing. They’ve had someone who was vaccinated who had been positive for COVID and then people are a little nervous because they had contact with this person,” said Muller.

Other cities like Cambridge are adding test sites based on demand, although not to the prior levels of availability. The former Church Street location in Harvard Square recently reopened for free walk-in tests on Sundays.

Some residents have taken to Twitter to complain about the lack of available test days and sites, to which Vice Mayor Alanna Mallon recently responded, “We just added a 3rd day in Harvard Square, and Mayor Siddiqui working on a 4th.”