Four months ago, the Maine Centers for Disease Control published a COVID-19 vaccination plan that included three packed pages laying out the order in which the shots – which did not yet exist – would be administered.

The plan created a virtual line that started with high-risk health care workers and people who live in nursing homes, followed by 12 other categories of Maine residents listed in order of whose job, living situation or underlying health conditions put them at an elevated risk of getting seriously ill or dying if they were infected.

On Friday, that plan was replaced by a single sentence: People in their 60s are eligible for vaccines this month, those in their 50s will be eligible in April, those in their 40s in May, those in their 30s in June and those younger than 30 after that.

Critics were quick to point out the unintended consequences of a plan that uses only one criterion to determine everyone’s place in line. It was easy to pick out individual examples where the new rules didn’t make sense. Should a healthy 50-year-old who can work from home really be vaccinated before a 40-year-old cancer survivor or a 30-year-old teacher?

Maybe not, but no system is going to be perfect. If the goal is getting the vaccine distributed fairly and efficiently while avoiding as many deaths and serious illnesses as possible, the age-based approach is the right way to go.

Gov. Mills explained Friday that age is the most reliable predictor of serious consequences resulting from a COVID infection.

So far, 98 percent of deaths from COVID-19 in Maine have been people aged 50 and older. People in their 50s have been eight times more likely to die from COVID than Mainers under age 50. The death rate is 23 times higher for those in their 60s and 214 times higher for those aged 70 and older.

The age-based vaccine system has the advantage of simplicity. Every Mainer will know their place in line, and people distributing the shots will not have to determine whether an individual’s job qualifies them for a shot, or whether someone’s underlying health condition puts them at “significantly higher risk” or just “moderately higher risk.” All that will need to be verified is the patient’s date of birth.

The public can have more confidence in a simple system than in a complex one that leaves too many opportunities to jump in line.

And in our race against COVID variants, a fast and efficient vaccination program is essential. Every person who can resist infection means one less potential host where the virus can mutate.

There are good reasons to be hopeful. Maine is expecting a surge in availability of vaccine doses, and new vaccine clinics are opening around the state to deliver them.

An efficient plan that will minimize illness, deaths and bureaucratic delays is the best way forward.