A special plane carrying a consignment of Ebola vaccine landed in Guinea on Monday night.
A dust storm in the Sahara forced the aircraft off course on Sunday when it was diverted to Senegal.
Vaccinations are to begin in Guinea’s capital, Conakry, on Tuesday.
Most of the 11,000 doses are to be taken to the south-eastern town of N’Zerekore.
Five people have recently died there from Ebola.
It’s West Africa’s first outbreak of the deadly hemorrhagic fever since 2016.