CHICAGO (NewsNation Now) — When August began, Dr. Francis Collins was still not convinced people who were fully vaccinated against COVID-19 would need a booster dose anytime soon. Breakthrough cases were (and still are) rare, and the vaccine is keeping most of those patients out of the hospital.

However, he said he was presented with data within the last 10 days he couldn’t ignore.

“You can see the trend, let’s prepare for it,” the director of the National Institutes of Health said on NewsNation Prime.

The plan, as outlined by the chief of the Centers for Disease Control and Prevention and other top health authorities, calls for an extra dose eight months after people get their second shot of the Pfizer or Moderna vaccine. The doses could begin the week of Sept. 20.

Officials said it is “very clear” that the vaccines’ protection against infections wanes over time, and they noted the worsening picture in Israel, which has seen a rise in severe cases, many of them in people already inoculated.

They said the U.S. needs to get out ahead of the problem before it takes a more lethal turn here and starts leading to increased hospitalizations and deaths among the vaccinated.

The CDC announced this month it believes around 1 million Americans have gotten an unauthorized third dose already.

Critics argue the U.S. should not use doses to turn moderate breakthrough infections into mild ones, and instead should donate them to countries with minimal access. President Biden Wednesday called this a “false choice” and believes America can do both at once.

This is only a plan until the FDA signs off on it, and it only applies to adults. Children between 12-17 are still being studied, Collins said.

“Exactly how you pick the right dose when the person is smaller has to be worked out,” he said. “So that data is being generated will be submitted to FDA we believe in the next few weeks, then FDA will have to look at it and make a judgment.”

Authorization for any doses for kids under 12 is still months away. Collins does not believe it will happen “before pretty near the end of the calendar year.”

A study is ongoing about just how different the delta variant is from previous versions of COVID-19 that have flared up in this country. Collins said it’s definitely more contagious and possibly causes more severe illness in those it infects.

He said the virus will probably move from being a pandemic to an endemic disease, which means it never goes away but only flares occasionally. The flu is an example of an endemic virus. Collins added vaccines were the key to removing the virus’ claws.

“We can get through this, we just have to keep getting ahead of this virus instead of having it get ahead of us,” he said.