The European Union will be returning some 20 million doses of Johnson & Johnson's COVID-19 vaccine that were imported from a plant in South Africa, and the shots filled and finished there will no longer leave the African continent.

African Union special envoy Strive Masiyiwa, who heads the regional bloc's COVID-19 Vaccine Acquisition Task Team, told reporters Thursday that the decision was made at a meeting last week between South African President Cyril Ramaphosa and European Commission President Ursula von der Leyen.

Johnson & Johnson's South African partner, Aspen Pharmacare, has a contract to import the drug substance for the one-dose vaccine from the American pharmaceutical giant and then package them -- the so-called fill-and-finish process -- at its facility in Port Elizabeth, South Africa.

"All the vaccines produced at Aspen will stay in Africa and will be distributed to Africa," Masiyiwa said at a press conference Thursday.

The decision came amid criticism of the arrangement, with the World Health Organisation's director-general, Dr. Tedros Adhanom Ghebreyesus, who is Ethiopian, saying last month that he was "stunned" that vaccines will be shipped from Africa to Europe. Just 3% of people in Africa, the world's second-largest, second-most populous continent, are fully vaccinated against COVID-19. In comparison, 57% of people are fully vaccinated in the European Union and 52% in the United States, according to the WHO.

Nearly 300 children are currently hospitalized with COVID-19 in Texas, state data shows.

According to the Texas Department of State Health Services' online COVID-19 dashboard, which was last updated on Thursday afternoon, there are 282 pediatric patients in hospitals across the Lone Star State.

The data also shows there are 81 staffed pediatric intensive care unit beds available in all of Texas.

-ABC News' Gina Sunseri

Dr. Paul Offit, a member of the U.S. Food and Drug Administration's vaccine advisory committee, said a two-dose COVID-19 vaccine "appears to be enough" to curb infection, rather than adding a booster shot.

"You look at states in the United States that have high immunization rates with a two-dose vaccine, it appears the two doses appears to be enough to be able to control this infection," Offit, who is also the director of the Vaccine Education Center at Children's Hospital of Philadelphia, told ABC News on Thursday night. "I think the critical issue here is not going to be boosting the vaccinated. I think if we really want to get on top of this pandemic, it's going to be about vaccinating the unvaccinated."

The FDA's vaccine advisory committee is set to hold a key meeting on COVID-19 vaccine booster shots on Sept. 17, just three days before the Biden administration plans to begin offering the shots to Americans.

"If the companies or the FDA can make a case that there has been an erosion in protection against severe critical disease and that that erosion in protection against severe disease would be mediated or eliminated by a third dose, then we could move forward," Offit said. "But to date, we really need to see those data to be able to make that decision."

Two studies to be published Friday found fewer pediatric hospitalizations among children and communities with higher vaccination rates, the director of the U.S. Centers for Disease Control and Prevention said.

In one study, national data from August showed that children were nearly four times more likely to be hospitalized with COVID-19 in the states with the lowest vaccination rates when compared to states with the highest rates -- proof that "cocooning" children with vaccinated people keeps them safe, Dr. Rochelle Walensky said at a White House briefing Thursday.

The second study, which looked at hospitalizations rates in 12- to 17-year-olds across 14 states during July, found that adolescents who were unvaccinated were 10 times more likely to be hospitalized with COVID-19 than their fully vaccinated peers, Walensky said.

"Both studies, one thing is clear: cases, emergency room visits and hospitalizations are much lower among children and communities with higher vaccination rates," Walensky said. "We must come together to ensure that our children, indeed, our future, remain safe and healthy during this time."

-ABC News' Cheyenne Haslett