Dave Lacknauth, executive director of pharmacy services at Broward Health Medical Center, shows off a bottle containing the Pfizer/BioNtech Covid-19 vaccine on December 17, 2020, in Fort Lauderdale, Florida. | Joe Raedle/Getty Images

America’s Covid-19 vaccine supplies are growing fast. Now comes the next fight.

In the coming months, America could reach a point when it has more Covid-19 vaccines than people want.

Between efforts from the federal government and drug companies to step up manufacturing and distribution, the US’s vaccine supply is truly increasing: At least 150 million doses are expected through March — a rate of more than 3 million shots a day, the kind of speed the country needs to reach herd immunity, when enough people are protected against the virus to stop its spread, this summer.

But public health experts are increasingly warning of what may