GENEVA – The vaccines alliance Gavi has signed an agreement to buy 200 million doses of the one-shot Johnson & Johnson coronavirus vaccine in a boost to the U.N.-backed initiative to distribute vaccines to poor countries.

In a statement Friday, Gavi said the deal was made “with the goal” of the 200 million vaccines being made available this year. Earlier this week, the U.N. initiative known as COVAX suffered a major setback when its biggest supplier, the Serum Institute of India, announced it would not be exporting any more vaccines until the end of the year, in order to deal with the explosive situation on the subcontinent.

Gavi said the 200 million J&J doses would be available to both poor countries relying on vaccines, in addition to rich countries who joined COVAX as a way to guarantee themselves extra vaccine shots. Earlier this month, Canada received more then 600,000 doses of AstraZeneca from COVAX.

“As a one-dose vaccine, the J&J vaccine has particular relevance for places with difficult infrastructure,” said Gavi CEO Dr. Seth Berkley. Gavi said it is still in discussions with J&J to buy another 300 million vaccines for next year.

Still, J&J has suffered multiple production problems in the U.S. and Europe and regulators earlier paused the use of the vaccine to investigate reports of a rare blood clot. Officials concluded there were rare instances of unusual blood clots linked to the shot but that its advantages outweighed the risks.

The U.S. Food and Drug Administration shut down the production of J&J vaccines at one company in April after finding serious quality control problems.