Dr. Deborah Birx told Americans on Wednesday at the White House that the mortality rate for coronavirus would be higher in the early stages of the fight against the disease.

“The mortality is higher at the beginning because you’re diagnosing the sickest, the ones who came in quite ill,” she said to reporters during a White House press briefing on Wednesday afternoon.

Birx added that the risk for serious illness among the majority of Americans was low but that they could transmit the disease to the elderly.

“I just want to remind the American public that still the risk for serious illness in the majority of Americans are low,” she said. “But that doesn’t mean that you can’t transmit it to one of those higher-risk groups, and that’s why we’re asking for all Americans to take responsibility.”

The people currently dying from the disease, she explained, were diagnosed two to three weeks ago with the illness or where it had been contracted in nursing homes.

“If we’re going to solve this with a lower death rate, we have to protect the elderly because of their percent is much higher in mortality than any other age group,” she said.

But Birx also said that more young people in the millennial generation were contracting the virus than expected in countries like Italy and France.

“It may have been that the millennial generation, our largest generation, our future generation, that will carry us through for the next multiple decades — there may be a disproportional number of infections among that group,” she said.

President Donald Trump urged all young people to adhere to the guidelines from the federal government urging them to stop gathering in large groups.

“We don’t want them gathering, and I see they do gather, including on beaches, including in restaurants,” Trump said. “Young people, they don’t realize. They’re feeling invincible.”