Cara Sacks, co-chair of Mainers for Health and Parental Rights, speaks at a news conference before her group delivered petitions to the Maine secretary of state's office, Wednesday, Sept. 18, 2019, in Augusta, Maine. The group says they gathered more than 92,000 signatures in support of the people's veto of government-mandated vaccine bill. Credit: Robert F. Bukaty | AP

AUGUSTA, Maine — Maine will vote on a people’s veto effort aimed at repealing a new school vaccination law passed by the Democratic-led Legislature after Secretary of State Matt Dunlap’s office said Thursday the effort qualified for the March 2020 ballot.

The certification was no surprise. The group running the challenge, Mainers for Health and Parental Rights, said last month that it turned in more valid signatures from registered voters than the 63,000 required. Dunlap’s office said Tuesday it validated 79,000 of them.

The people’s veto effort would repeal a bill seeking to eliminate nonmedical exemptions for required school vaccinations in Maine. It was signed by Gov. Janet Mills in May as a response to rising opt-out rates, but it won’t go into effect unless voters uphold it in the March election.

Maine had a higher measles vaccine opt-out rate than all but six states during the 2017-18 school year. The bill was backed by physicians, but it drew hundreds of opponents at a legislative hearing in March making arguments that ranged from personal freedom — the main argument from people’s veto backers — to a debunked link between vaccines and autism.

Mainers for Health and Parental Rights raised more than $161,000 to support the campaign through September’s end, with a Portland Press Herald review finding that $51,000 alone came from chiropractors, a class of licensed health professionals who are not medical doctors.

The people’s veto vote will come during a new presidential primary election where Democrats have more than a dozen well-known candidates running for the presidential nomination. The timing of the election was not immediately clear after inconsistent guidance from Dunlap’s office.

Maine Republicans will also hold a primary, but President Donald Trump is unlikely to face serious competition for the nomination. Any imbalance in the electorate could benefit the law’s backers, who have organized under a political committee called Maine Families for Vaccines.

Opponents of the law have rejected that notion, saying their coalition includes many Democrats. Cara Sacks, the co-chair of Mainers for Health and Parental Rights, said in a Thursday statement she was confident voters would reject “this incredibly punitive and overreaching law.”

Dr. Laura Blaisdell, a Yarmouth-based pediatrician who co-founded Maine Families for Vaccines, said in a statement the group was “confident that Maine voters will reject this attempt to leave schools vulnerable” to preventable diseases.”

Michael Shepherd joined the Bangor Daily News in 2015 after time at the Kennebec Journal. He lives in Augusta, graduated from the University of Maine in 2012 and has a master's degree from the University...