"The availability of COVID-19 vaccines and the procurement terms were still uncertain at the time of finalizing the 2021 budget," Buhari said in his letter to parliament.
Nigeria plans to issue $3 billion or more in Eurobonds as international capital markets (ICM) open up and interest rates decline, after the coronavirus pandemic disrupted markets last year.
Buhari said the health ministry and primary healthcare agency has developed a COVID-19 program for the country that intends to vaccinate 70% of eligible Nigerians this year and next.
In addition to purchase of COVID-19 vaccines, the president asked for more funds for the military.
"Our security and law enforcement agencies urgently need to procure additional equipment and other resources in response to the prevalent security challenges across the country," he said.
Nigeria faces rising insecurity - ranging from mass abductions at schools, kidnappings for ransom, armed conflict between herdsmen and farmers, armed robberies and various insurgencies - that has been a drag on growth and job creation.