The first importation of the disease to the United States poses little risk to the general public, say officials.
A WHO team moves from Riyadh to Jeddah, while other experts call for collaboration.
A US-Chinese team of scientists has reported the discovery of three human monoclonal antibodies with a potent ability to neutralize MERS-CoV (Middle East respiratory syndrome coronavirus), a find they say may point the way toward a drug to prevent or treat the infection.
The MERS onslaught that began in late March rolled into May with 11 new cases.
The April MERS surge continued, with 16 more cases reported in Saudi Arabia.
The results further augment the evidence that camels are a source of human infections.
The Saudi count grows to 345, including 105 deaths, as a local medical conference is shelved.
Saudi Arabia reported 26 cases and Egypt its first, but new sequencing findings showed no major mutations.
Two research teams say they have identified antibodies against the novel virus.
Some have theorized about changes in the virus, but preliminary data show no mutations so far.
