Nigeria and Kenya are to receive Covid-19 vaccines from the UN-backed Covax programme on Tuesday.
Kenya will get 1.25 million doses of the AstraZeneca Oxford vaccine and vaccinations are expected to start immediately, according to health minister Mutahi Kagwe.
Nigeria will receive 3.92m vaccine doses, becoming the third West-African country to benefit from the facility.
Priority will be given to front line health workers and the elderly.
The country expects to receive a total of 16m doses from Covax in the next few months.
Twenty-four African countries are expected to receive Covid-19 vaccines soon from the UN-backed Covax programme.
Ivory Coast on Monday became the first country to roll out vaccines offered by the Covax programme.