After a single-day count of over 400 new COVID-19 cases in Boston -- the highest since June's infection peak -- Mayor Marty Walsh is bracing for the possiblity that infection rates will continue to climb in the wake of this Thanksgiving weekend.

Many residents, Walsh says, traveled or left their homes to visit with relatives despite public health advisaries urging them to stay home. That could mean a wave of new infections in coming days, Walsh said.

"We're going to be monitoring the data closely as it comes in to make sure we don't see large spikes," Walsh said. "In the meantime, we have to continue to do everything we can to stop spreading the virus."

Walsh urged, as he has done at every press availability in recent weeks, for all residents to get tested for COVID-19 if they have attended gatherings beyond their household and to make testing a part of their regular routines.

Despite the cautionary tone, Walsh said there is also cause for cautious optimism: City-wide COVID-19 infection rates have seen a small but steady decline over the past two or three weeks -- and infection rates have remained stable, or declined slightly, in neighborhoods hit hardest by coronavirus.

Walsh said the city's hospitals and health care infrustructure remain well within capacity to treat patients at current infection rates.

And the mayor voiced optimism about the possiblity of re-opening Boston schools for in-person learning, after the BPS re-opening plan was halted indefinitely due to rising COVID-19 cases.

"I'm not anticipating our schools reopening fully before Christmas, but I'm expecting we'll have some clarification as to what the reopening plan will be after Christmas," Walsh said.

When you're dealing with a district like Boston you're dealing with one hundred twenty-plus schools, you're dealing with different grade configurations, different transportation challenges certainly schools department is working hard to figure out what are some of the safety requirements we can put in place to make sure we can reopen schools safely.

Noting a planned protest by parents demanding BPS schools reopen, planned to take place on City Hall Plaza Wednesday, Walsh expressed sympathy, along with some tough love.

"I support you," Walsh said. "But right now, today, we are not prepared for that. Not when you have four hundred cases today."

Walsh noted another piece of good news: Boston has received AAA credit ratings from top rating agencies for the eighth year in a row, despite the devestating economic impact the pandemic has had on the city's economy.

"That's an outstanding achievement," Walsh said, adding that the rating "means we will be able to invest more of our resources in affordable housing, in climate resilience, in new schools and libraries, in green spaces and bike lanes."