COVID-19 updates: 345 children currently hospitalized with coronavirus in Texas

Eight school districts in Florida told the state's education commissioner that they would not reverse their mask requirements for students, clearing the way for the state to retaliate by withholding the salaries of school board members.

The eight districts -- Duval, Hillsborough, Indian River, Leon, Miami-Dade, Orange, Palm Beach and Sarasota -- each wrote a letter to Commissioner Richard Corcoran Wednesday saying they believed they were following state law and had no plans to stop requiring face coverings for students.

Corcoran had given each district until 5 p.m. Wednesday to reverse their mandates, threatening to recommend to the state education board that it withhold the salaries of board members if they did not change course.

The state education department announced Monday it would take such action against board members in Alachua and Broward counties over their school mask mandates.

On Friday, a Florida judge ruled that school boards can enact student mask mandates and ordered the state education department to stop enforcing a state rule requiring districts to allow parents to opt-out.

-ABC News' Will McDuffie

A new study out of Israel finds that certain cancer patients may see roughly equal vaccine protection as the general population. 

Specifically, the study found a group of 154 cancer patients with solid tumors had an antibody response roughly equivalent to an equally-matched group of people without cancer six months after their second Pfizer shot. A subset of cancer patients undergoing chemotherapy, however, were the most likely to have antibody levels below a detectable threshold.

The study also found the Pfizer vaccine was safe for solid tumor cancer patients. 

The study implies that not all cancer patients may need a third booster shot to achieve equal levels of protection as the general population. Presently in the U.S., the CDC and FDA say "moderate to severely" immune compromised people need a third shot -- which comprises roughly 3% of the U.S. population. 

-- ABC News’ Sony Salzman

Liberty University switched all residential classes to be online and suspended indoor gatherings as the campus -- which does not require vaccinations for students or staff -- grapples with a new surge in COVID-19 cases. 

The college reported 430 active cases of students with COVID-19 on Wednesday, according to ABC News’ local affiliate WSET-TV. This is more than the total number of cases at four neighboring Virginia colleges combined. The University of Virginia, Virginia Commonwealth University, Virginia Tech and James Madison University have reported a total of 125 students with active cases total. 

The latter four universities require students to get the COVID-19 vaccine and wear masks, while Liberty does not require either.

The World Health Organization warned Thursday that Africa, the world's second-largest and second-most populous continent, is set to miss the global goal of vaccinating the most vulnerable 10% of every country's population against COVID-19 by the end of September.

Forty-two of Africa's 54 nations -- nearly 80% -- will fall short of that target, set in May by the World Health Assembly, if the current pace of vaccine deliveries and vaccinations holds, according to the WHO.

“With less than a month to go, this looming goal must concentrate minds in Africa and globally," Dr. Matshidiso Moeti, the WHO's regional director for Africa, said in a statement Thursday. "Vaccine hoarding has held Africa back and we urgently need more vaccines, but as more doses arrive, African countries must zero in and drive forward precise plans to rapidly vaccinate the millions of people that still face a grave threat from COVID-19."

With more COVID-19 vaccines expected to be delivered across Africa from the global vaccine-sharing initiative COVAX as well as the African Union, the WHO said there could be enough doses to meet the 10% target. Nine African countries have already reached the goal and, at the current pace, three more are set to do so. Two more could meet it if they speed up vaccinations, according to the WHO.

But while many African nations have sped up vaccinations as shipments increased, the WHO said that 26 countries have used less than half of their doses.

So far, some 39 million people in Africa -- just 3% of the continent's population -- 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.

"The inequity is deeply disturbing," Moeti said. "Just 2% of the over five billion doses given globally have been administered in Africa. Yet recent rises in vaccine shipments and commitments shows that a fairer, more just global distribution of vaccines looks possible."