Faisal Shuaib, head of Nigeria’s National Primary Health Care Development Agency, said health officials in Africa's most populous country were left with little choice after receiving the donated doses that didn't have much shelf life left.
"We had developed countries that procured these vaccines and hoarded them," he said. "At the point they were about to expire, they offered them for donation."
Last week Shuaib had announced that Nigeria would no longer accept such donations, though he did not specify publicly what officials considered too short a shelf life.
Only 2% of Nigeria's 206 million people are fully vaccinated, and health officials have set an ambitious goal of vaccinating more than a quarter of the population by February. While hesitancy has been high, the country's vaccination rate has nearly doubled over the past week.
Nigeria has been seeing a spike in confirmed infections since it detected the highly-infectious omicron variant in late November, recording a 500% increase in cases over the past two weeks, according to the Nigeria Center for Disease Control.
The 2,123 new COVID-19 infections it confirmed on Tuesday was the highest daily tally since last January and the second highest since the pandemic began.
"If we are going to overcome this COVID-19 pandemic, we have to do better job of ensuring better supply of the COVID-19 vaccines," said Shuaib. "No country will be able to eradicate COVID-19 ... until all countries are able to eradicate it."