The Federal Government has directed the 36 states to suspend COVID-19 vaccination.
This follows apprehension about a likely delay in the further supply of the vaccine.
There are also fears that the vaccine may not be available for the second dose for Nigerians already vaccinated.
The directive was issued to the states by the Executive Director of the National Primary Healthcare Development Agency, Dr. Faisal Shuaibu.
The Astra-Zeneca vaccine is given in two doses.
Nigeria was given 3.9 million sides of the vaccine last month and some states have made significant progress in administering the first shot.
They are to receive a second shot by next month.