President Joe Biden will announce plans Wednesday to acquire an extra 100 million doses of Johnson & Johnson's COVID-19 vaccine, giving the United States surplus capacity should other makers run into manufacturing problems.
Biden was set to make the announcement during a meeting with executives from J&J and Merck, an administration official said.
Merck is working with J&J to help produce its vaccine.
The president said earlier this month the United States was on track to have enough vaccine for every adult by the end of May after the Food and Drug Administration granted emergency use authorization to the J&J vaccine.
The country has deals for 300 million doses each of the vaccines manufactured by Pfizer and Moderna -- which both require two shots -- and 100 million doses from J&J.
By doubling the J&J the order to 200 million, the administration is looking to pad out stocks in case of production issues with Pfizer or Moderna.