Pope Francis presided at an outdoor prayer service in the Vatican on Saturday, with about 130 people in attendance.
According to Reuters, it was the largest gathering there in nearly three months.
Most wore masks except for when they led prayers at the microphone.
Francis, 83, sat several meters away from most people during most of the service.
He did not wear a mask.
The Pope prayed that the Madonna would touch the consciences of world leaders to divert arms expenditures to pandemic research.
Earlier this month, Francis called for international scientific cooperation to develop a COVID-19 vaccine and said any successful one should be shared globally.
In closing, Francis said national leaders should take a far-sighted attitude, helping the neediest now and creating long-term economic and social solutions.