Geneva - The World Health Organization held Tuesday an online conference of scientists from various regions to discuss the nature of the new influenza A (H1N1) virus, which primarily seemed to be affecting younger people.

Meanwhile, the UN's health agency updated the number of laboratory-confirmed cases of the new virus to 1,490 human infections in 21 countries. These included 30 death, all in Mexico except for one in the United States.

Keiji Fukuda, the WHO's chief of health security, said scientists have realized that on average the infected people were in their mid-20s and the overwhelming bulk of cases were in people below the age of 60.

He noted that most of infections were "reported in people who are traveling," leading the researcher to question if "is this the disease or the group traveling."

It was also possible older people had certain biological protections against the illness.

Also Tuesday, the WHO was to begin shipping 2.4 million doses of anti-viral drugs to its regional stockpiles and to some 72 countries. The UN has said it would give doses to Mexico and some of the world's poorest nations.

Many of the new confirmed cases were from Canada, which had a total of 140 and the United States, though the WHO could not confirm the latest numbers from there as it was being updated. Mexico, the hardest-hit country, had 590 confirmed human infections.

In Europe, Spain led with 54 cases while Britain now had 18 confirmed infections. Fukuda said there was no evidence of sustained human to human transmission in the continent.

While the previous scientific meet led to the WHO raising its pandemic influenza alert up one level to phase 5, WHO spokeswoman in Geneva Fadela Chiab said there was "no link" between the meeting and the alert level.

While the alert system tracks geographic spread it does not contain levels for the severity of the disease. So far, the new virus has shown itself to be mostly mild but fatal in some cases.

Fukuda said that in general new pandemics have been more mild than in the past, but the legacy of the 1918 Spanish flu outbreak, which killed tens of millions, was keeping the WHO on its toes.

Though medicine had improved since then, health care centres could become overwhelmed if authorities did not stay alert.

"The technology (today) is excellent but does not ensure medical system themselves can handle a large number of people coming in outside of the usual range," he said.

By watching the influenza develop, WHO was hoping it could prevent a sudden influx.

"It is extremely important for countries to share information," said Fukuda.

The WHO repeated its recommendations that travel bans and border closures would not stop the spread of the virus but would be "highly disruptive to the global community."

The incubation period of the disease, which could be up to a week, and its geographic spread would make travel restrictions ineffective, officials have said.

Also, the organization reiterated its recommendation that the virus could not be contracted by eating pork products, provided they were properly prepared and cooked.