US to buy additional 100 million doses of J&J's Covid-19 vaccine

President Joe Biden is announcing Wednesday the US is buying an additional 100 million doses of the single-shot Johnson & Johnson coronavirus vaccine.

The drugmaker is already obligated to supply 100 million doses to the federal government by the end of June. The additional vaccine would be delivered in the months following. A White House official previewed the news on the condition of anonymity before the president's remarks.

The US is set to receive enough doses of the three approved vaccines by the middle of May to cover all adults. The surplus would ensure supply to cover young adults and children, pending the result of safety and efficacy trials. They could also be used as potential boosters to further protect against emerging virus variants, or be shared with allies overseas once Americans are protected.