Here’s how pandemic rules will shape the U.N. gathering.

Unlike in 2020, when the U.N. General Assembly session was conducted almost entirely virtually because of the pandemic, more than 100 world leaders and other high-ranking representatives intend to deliver their speeches in person this year.

But access to the 16-acre United Nations complex in Manhattan remains strictly limited, with mandatory mask-wearing and other Covid prevention measures. Ambassador Linda Thomas-Greenfield of the United States told reporters that the measures were meant to ensure that the General Assembly “does not become a superspreader event.”

Confusion erupted last week over a New York City requirement that all General Assembly participants show proof of vaccination. This year’s president of the General Assembly, Foreign Minister Abdulla Shahid of the Maldives, endorsed the requirement. But exactly how it will be enforced is unclear.

U.N. officials have said that the organization’s headquarters staff must be vaccinated, but that an honor system remains in place for visiting V.I.P.’s and other guests.

In what appeared to be a good-will gesture, New York City’s municipal government deployed a mobile vaccine clinic outside the United Nations complex, offering free testing and Johnson & Johnson vaccines.

Many speakers this year still chose to deliver their addresses via prerecorded video, as was done by all leaders last year when vaccines were still under development and each delegation in the General Assembly hall was limited to two people. Nearly all events at the 2020 event were conducted virtually.

This year each member state may seat as many as four people in the General Assembly hall.

President Jair Bolsonaro of Brazil, an avowed vaccine skeptic whose popularity has fallen at home partly over what critics call his disastrous handling of the pandemic, vowed ahead of his speech that he would not be vaccinated.

He was infected with Covid more than a year ago and then claimed to have cured himself by taking hydroxychloroquine, an antimalarial drug that has not been shown to be effective in Covid treatment.