The United States is shipping nearly 1.7 million doses of Covid-19 vaccine to Uganda, a White House official said Thursday, in the latest wave of jabs donated to stem the global pandemic.

"Thanks to the US commitment to playing a leading role in ending the pandemic everywhere, the United States is shipping 1,684,800 doses of Pfizer vaccine to Uganda," a senior US official said, asking not to be named.

The vaccines are being shipped, starting Thursday, through Covax, the global distribution initiative co-led by public-private partnership Gavi.

On Wednesday, White House Covid-19 response coordinator Jeff Zients announced that the United States had reached the milestone of 400 million vaccine doses delivered to 112 countries.

"Four hundred million doses shipped for free with no strings attached," Zients said.

Pupils walk past wall posters calling for Covid-safety measures at Nalya Primary school in Kampala
Pupils walk past wall posters calling for Covid-safety measures at Nalya Primary school in Kampala AFP / Badru KATUMBA

Washington has pledged 1.1 billion shots to the rest of the world -- more than any other country -- and has already sent vaccines to countries ranging from Guatemala to Papua New Guinea.

The US shots often cross paths with shipments from China and Russia in what has been dubbed "vaccine diplomacy," although the US official insisted "we are sharing these doses not to secure favors or extract concessions."

According to figures from Johns Hopkins University, just 4.36 percent of Uganda's population is fully vaccinated.

Uganda ended the world's longest school closure earlier this month, ordering millions of students back to the classroom nearly two years after learning was suspended because of the coronavirus pandemic.

The country of some 45 million people recorded 160,778 Covid-19 cases, with 3,497 deaths, according to latest figures from Johns Hopkins.