Francis spoke in his yearly address to the diplomatic corps accredited to the Vatican, sometimes called his "State of the World" address because it is a broad survey of the global situation.

His words to diplomats from nearly 200 countries marked the closest he has ever come to a de facto backing of vaccine mandates, which have become controversial in Italy and other European countries.

"We have realised that in those places where an effective vaccination campaign has taken place, the risk of severe repercussions of the disease has decreased," he said.

"It is therefore important to continue the effort to immunise the general population as much as possible".

Francis, who dedicated about a fifth of his six-page address to the pandemic, warned against ideological statements regarding vaccinations.

"Sadly, we are finding increasingly that we live in a world of strong ideological divides. Frequently people let themselves be influenced by the ideology of the moment, often bolstered by baseless information or poorly documented facts," he said.

"Vaccines are not a magical means of healing, yet surely they represent, in addition to other treatments that need to be developed, the most reasonable solution for the prevention of the disease," he told the diplomats gathered in the Vatican's frescoed Hall of the Benedictions.

By saying that "health care is a moral obligation" in the context of a speech supporting vaccinations, Francis appeared to be responding to Catholics and other Christians, particularly in the United States, who say they have a religion-based right of conscientious objection to vaccines.

Francis, who is fully vaccinated, called for a global political commitment "to pursue the good of the general population through measures of prevention and immunisation".

He renewed his appeal for the equitable distribution of vaccines to poor nations, saying that "monopolistic rules" regarding patents should be put aside for the greater good.

Francis also reiterated his defence of migrants, saying each country should accept as many as possible and that responsibility for their integration should be shared.

On climate change, he said the results of last year's COP26 summit in Glasgow were "rather weak in light of the gravity of the problem" and hoped that action on global warming could be consolidated at COP27 planned for Egypt in November.

He repeated calls for dialogue in areas of conflict or crisis such as Lebanon, Ukraine and Myanmar as well as his call for a ban on the possession of nuclear weapons.

The Vatican, the world's smallest state, has diplomatic relations with 183 states.