The plan to allow more younger adults to get second COVID-19 boosters is being scrapped. Three administration officials told NPR that the next generation of boosters will be available in the fall.

The new strategy came after a debate within the administration about trying to balance protecting people this summer with keeping people safe next winter, when the country will probably get hit by yet another surge.

A new booster campaign was supposed to be launched this summer to encourage more people to get double-boosted in order to protect them against the highly contagious BA.5 variant.

There was concern that that would interfere with a booster campaign in the fall.

Giving two boosters so close together could increase the risk of myocarditis. Giving them so close together could make the second booster less effective.

Two booster campaigns too close together would make it difficult to convince people to get boosters.

The FDA is faced with a dilemma, because the immunity many people have gotten from getting vaccine has worn off. The most contagious version of the virus is making people more vulnerable.

Most people younger than 50 aren't eligible for a fourth shot if they have a cold or flu again.

The FDA was considering allowing second boosters for all adults. Allowing more people to be boosted with the original vaccine now could make it difficult to boost them with the updated, hopefully more protective vaccines in the fall to counteract the winter surge.

Moderna and Pfizer-BioNTech were racing against the clock to get new, "bivalent" boosters ready by October or November that target both the original strain of the virus and the omicron subvariants.

The FDA got assurances from the companies that they could deliver the new boosters in September, according to a federal official who is not authorized to speak publicly. The hope is that the new boosters will be available to children and adults in September.

There were differing reactions to the possibility of the shift.

It is thought to be the smartest strategy. Most younger, healthy people are still protected by three shots. Some experts say that boosting people again now and again in the fall could make them less willing to get a booster.

Dr. Monica Gandhi is a professor of medicine at the University of California, San Francisco. It's not possible to give a booster in 1.5 months or two months.

According to some experts, giving two shots too close together could have a negative effect on a person's health.

The senior fellow at the Kaiser Family Foundation thinks this is the right call. If you get a booster now, it may be counter- productive. It might prevent you from developing an immune response to the second booster dose.

Others are not so sure. The new vaccines might not be better.

John Moore says people shouldn't think of them as a magic bullet that will protect them. These aren't going to be magic bullet game-changers because they aren't much better than the already available vaccine boosters.

The new boosters can't be ready by September. Who knows if BA.5 will be the main bug in the fall and winter.

"I don't see the benefit waiting for a BA.5 specific booster since BA.5 may be in the rearview mirror and well past us by the time that's available," says Dr. Peter Hotez.

Some say that people younger than 50 should have the option to protect themselves.

Dr. Robert Wachter is the chair of the department of medicine at the University of California, San Francisco.

It will likely mean millions of preventable infections, thousands of preventable hospitalizations, and hundreds of preventable deaths.