WHO Director-General Dr. Gro Harlem Brundtland appealed to governments worldwide to work closer together in the fight against SARS, which has made more than 7,700 people ill in 31 locations.
"We can no longer rely on national efforts alone to implement the scaled-up system of global alert and response that the world now needs," she said.
Before delegates could enter the assembly room, they had to fill out a form stating they had no symptoms of severe acute respiratory syndrome and had not been in contact with SARS patients. Only then were they given the green sticker on their badges authorizing them to attend.
As the 10-day meeting got under way, WHO medical experts announced they have determined 16 people became infected with SARS on airplanes.
"There were 35 flights on which SARS-infected people who were symptomatic with disease traveled," said Dr. David Heymann, the United Nations health agency's chief of communicable diseases. "We know, however, that on only four of those planes was there actually passage of the disease. We believe that 16 people on four different airplanes got infected."
Of those, 14 were passengers sitting within four seats of the SARS patient and two were flight attendants, said Mike Ryan, the agency's coordinator of the global effort to prevent the spread of SARS.
"Proximity is a huge part of this picture. The vast majority have been within two rows in front or two rows behind. Not sharing toilets, not walking up and down the aisle, not sitting in the waiting area - none of those issues seem to be associated," Ryan said at a news conference at the WHO session.
All 16 cases occurred before March 23, four days before the health agency recommended that airlines screen passengers for signs of SARS and advised that suspected cases not be allowed to travel. SARS is not contagious unless symptoms are showing, experts say.