COVID-19 cases continue to be significantly lower in younger kids, even as some went back to school in-person, according to a new report from the Centers for Disease Control and Prevention. 

The incidence of COVID-19 in children, particularly those ages 0 to 10, has been lower than that of young adults and adults throughout the entire second half of 2020, according to the CDC. The incidence of COVID-19 cases in kids was higher as the age increased.

While older teenagers and young adults saw a surge of cases near the beginning of the school year, this was not seen in younger kids, "suggesting that young adults might contribute more to community transmission than do younger children," the report said.

Children also had significantly lower rates of hospitalizations, intensive care unit stays and death than adults, the study found.

Fewer COVID-19 tests are performed on children, so the actual incidence may be higher than the data that's available. 

Teacher and school employee transmission risk also were not included in the data. 

The CDC continues to recommend strict mitigation strategies to prevent transmission in schools that are in-person.

-ABC News' Dr. Rose Marie Leslie

Texas reported a record number of daily COVID-19 fatalities on Wednesday.

There were 405 new deaths, based on state health department data.

The state also reported 26,808 new and probable cases and 14,106 current hospitalizations. 

Late Tuesday, Texas became the second state to cross 2 million diagnosed cases of COVID-19, following California.

California and New Jersey officials on Wednesday announced new groups eligible for the vaccine.

In New Jersey, beginning Thursday, all residents ages 65 and above will be eligible, as well as people between the ages of 16 and 64 with medical conditions defined by the Centers of Disease Control and Prevention that increase risk for severe illness from COVID-19.

“This is folks with chronic, real-time health challenges,” Gov. Phil Murphy said.

The CDC defines those as: cancer, chronic kidney disease, chronic obstructive pulmonary disease, immunocompromised state (weakened immune system) from solid organ transplant, obesity and severe obesity, sickle cell disease, smoking, type 2 diabetes mellitus, pregnancy and heart conditions such as heart failure, coronary artery disease or cardiomyopathies.

"Smoking puts you at significant risk for an adverse result from COVID-19 and there are 2 million smokers in New Jersey that fit into this category," said Commissioner of the Department of Health, Judy Persichilli.

In California, people ages 65 and older are the next group eligible to get vaccinated.

“With our hospitals crowded and ICUs full, we need to focus on vaccinating Californians who are at highest risk of becoming hospitalized to alleviate stress on our health care facilities,” Dr. Tomás Aragón, director of the California Department of Public Health and State Public Health Officer, said in a statement.

ABC News' Eric Strauss contributed to this report.

Researchers at Ohio State University's Wexner Medical Center said Wednesday that they've have identified two new variants of the virus that causes COVID-19.

The first variant, which was found in just one person, contains a mutation that's similar to a mutation seen in the variants from the U.K. and South Africa, but it arose independently in the U.S., the researchers said. It is not known if it is more easily transmissible.

The second newly identified variant was found in about 20 patients in Columbus and also arose independently in the U.S., the researchers said. It does not contain any mutations in common with variants identified in the U.K. or South Africa, they said. Scientists said they found cases of this variant with increased frequency during late December, which could imply that it's more easily transmissible, but they emphasized that more studies are needed.

Peter Mohler, a co-author of the study and chief scientific officer at the Wexner Medical Center, said Wednesday, "we’re not ready to overreact," stressing, "this is very normal for a virus to mutate."

ABC News' Sony Salzman contributed to this report.