The great challenge of COVID-19 vaccinations has inverted from finding supply to keeping demand high. The dream of “herd immunity” requires needles into arms, and lots of them. Increasingly, a major challenge is persuading reluctant, busy or just plain lazy folks to get inoculated. 

An inventive — and, so far, successful — partnership of the Seattle Fire Department, Virginia Mason Franciscan Health and the Seattle Mariners models a promising route. On Tuesday, the Mariners became the first Major League Baseball team to offer the jab to anyone in the stadium for the game. This isn’t the most equitable way to immunize the masses; the shot is free, but tickets into T-Mobile Park cost money. However, it does bring convenience to a ready audience of ballgame spectators who, for whatever reason, hadn’t sought out shots during other hours. 

It worked — Seattle Fire tweeted that 153 people got dosed at Tuesday’s game, where they were able to choose from a first-of-two Moderna dose or a one-and-done Johnson & Johnson vaccine.

That doesn’t match the thousands of doses administered at mass inoculation sites, but it’s evidence meaningful progress toward the end of this pandemic can come from taking the means to stanch the contagion to where people already are. The Sounders FC began a similar vaccine pop-up for fans at Sunday’s home match. The opening of a vaccine clinic at Seattle-Tacoma International Airport is another approach that can help immensely. These vaccines don’t need sophisticated medical infrastructure at their delivery sites. They need available arms.

Health agencies, sports leagues and event planners, take note. The spring will bring crowds out for farmers markets, graduations and athletic events. Those ought to be viewed as opportunities to reach broad numbers of people with the medicine that can save lives.