Gov. Charlie Baker wants young people in Massachusetts to act responsibly and to take the coronavirus more seriously as the state approaches a second surge in cases lead mostly by residents under the age of 30 testing positive for the virus.

Baker said the state's share of positive cases has shifted from earlier in the pandemic, when mostly older people came down with the illness.

"Today, the under-30 crowd is now responsible for 37 percent of cases and the over-60 crowd makes up only about 18 percent of cases," Baker said at a press conference Tuesday.

The state reported 1,128 new cases of COVID-19 Saturday and 1,097 cases Sunday, with another 1,216 coming Monday — the highest levels of transmission the state has seen since May.

Baker blamed house parties and other unofficial gatherings for the severity of the spread and warned about Halloween parties this weekend.

"Hosting parties and big indoor gatherings is just not a good idea and won't be a good idea until there is a treatment or a vaccine," Baker said.

The next big holiday, Thanksgiving, traditionally sees young and old gather to celebrate. Baker says breaking traditions may become necessary this year to keep everyone safe. The governor recommended limiting Thanksgiving gatherings to only the household.

"Every family here in the Commonwealth needs to think long and hard about the well-being being of your loved ones before you make your plans. If you have a loved one who is high risk for COVID, it's simply a bad idea to risk exposing them," Baker said.

Asked if school reopenings are contributing to the spread of the virus among young people, Baker said "there is very little evidence that this virus spreads in schools." The governor pointed to the success parochial schools have had in keeping the virus at bay.

"The parochial schools have been in-person since mid-August and they are located, for the most part, almost completely, in high risk communities and they serve primarily people of color," Baker said, adding that the system's 30,000 students and 4,000 teachers and staff have generated fewer than 25 COVID cases.

Earlier in the day, Baker and Lt. Gov. Karyn Polito released a statement urging voters to reject a ballot question that would restructure how Massachusetts elections are held and create a ranked choice system.

“At a time when we need to be promoting turnout and making it easier for voters to cast their ballots, we worry that Question 2 will add an additional layer of complication for both voters and election officials, while potentially delaying results and increasing the cost of elections," Baker and Polito wrote in the statement.