The call from officials to get vaccinated is growing as a new COVID-19 strain spreads throughout the world including the U.S.

The Delta variant originated in India. It has since be reported in at least 60 countries.

In the United States, the variant is making up more than 6 percent of new cases. It has also become the dominant strain in the United Kingdom, where the variant accounts for about 60 percent of new cases.

“We cannot let that happen in the United States,” Dr. Anthony Fauci said, “Which is such a powerful argument to underscore what Dr. Walensky said, ‘To get vaccinated, particularly if you’ve had your first dose, make sure you get that second dose. And for those who have been not vaccinated yet, please get vaccinated.”

The primary push for vaccinations from CDC officials has focused on kids. Children over the age of 12 can be vaccinated.

Pfizer announced plans to test its vaccine in a larger group of children under the age of 12.

The study will involve up to 4,500 kids in the U.S., Finland, Poland and Spain.

The kids will be given smaller doses: 10 micrograms for 5-11 year-olds, and three micrograms for the age group of six months to five years of age.

“This isn’t anything unusual, it’s called an age de-escalation and a dose de-escalation study,” Dr. Fauci said, “And when you get down to the younger children it is not at all unusual to diminish the dose.”

A Pfizer spokesperson said the company expects data from 5-11 year-olds in September.

Pfizer would likely ask regulators for emergency use authorization later that month.

Data for children two to five years old could arrive soon after that.

And, data from the six months to 2 year-olds is expected to arrive sometime in October or November.

According to the CDC, more than seven million teens have received at least one dose of the vaccine in the United States.