The World Health Organization has approved the emergency-use listing of Johnson & Johnson's COVID-19 vaccine, the U.N. agency said Friday, broadening access to the shots.

It is the third COVID-19 vaccine after the two-shot regimens of Pfizer/BioNTech and AstraZeneca to receive backing from the WHO and the first to be done in a single injection.

The listing covers use in all countries and for the rollout of the vaccine platform COVAX and comes on the back of European Medicines Agency (EMA) authorization announced on Thursday.

"Every new, safe and effective tool against COVID-19 is another step closer to controlling the pandemic," WHO Director-General Tedros Adhanom Ghebreyesus said in a statement.

"But the hope offered by these tools will not materialize unless they are made available to all people in all countries."

The WHO also welcomed the one-shot administration as facilitating vaccination logistics.

J&J's chief scientist Paul Stoffels told Reuters on Thursday the company expects to produce up to 3 billion doses of the vaccine next year, after previously pledging to deliver 1 billion globally by the end of 2021.

The WHO said that, under an emergency-use listing, companies have to commit to generating further safety and efficacy data to enable full licensing.