More than 30 percent of Bostonians have received at least one dose of a Covid-19 vaccine, Mayor Janey said Tuesday as she urged continued vigilance with the city experiencing an uptick in virus activity.

“I continue to be worried about this pandemic and how it is impacting the residents of this city,” Janey said at a briefing. She said it is “troubling anytime we see an increase in activity” and that she will work with public health officials to monitor metrics “so that we can adjust if we need to roll back some of the loosening of the restrictions that have already happened at the state level.”

Janey said that 130 new cases were recorded in Boston on Monday and two recent deaths linked to the coronavirus were reported. She said the city’s positive test rate is 4.2 percent, up from 3.7 percent, illustrating “that many people are still getting Covid.”

“The change is largely due to a higher rate of infection among younger residents,” Janey said. “More than half of the new cases in the past two weeks have come from Bostonians under the age of 29.”

Most young people are still not eligible to receive vaccines, but will become eligible on April 19. Boston’s cumulative caseload stands at 63,748, and 1,341 city residents with the respiratory disease have died, according to data from the city’s public health commission.