A CDC Image of H1N1 influenza virus

The Swiss pharmaceutical company Novartis says it has produced a first batch of a vaccine to fight the H1N1 swine flu virus, weeks ahead of expectations.

The company said Friday that producing the vaccine proved to be quicker through cell-based production rather than eggs, the usual method of producing vaccines.

Novartis says clinical trials will begin in July.

More than 30 governments have asked Novartis to supply them with a swine flu vaccine.

The announcement comes a day after the World Health Organization declared the swine flu virus a pandemic as infections climbed to nearly 30,000 cases in 74 countries.  This was the first declaration of a global flu pandemic in more than 40 years.

The United Nations agency issued the declaration Thursday after it held an emergency meeting with flu experts in Geneva.  WHO Director-General Margaret Chan said that although the virus is now "unstoppable," the danger that it poses is "moderate."

Officials note that declaring a pandemic does not mean the disease has become more severe, but that there is an increasing number of infections in different geographical locations.  The agency also is reiterating its advice to countries not to close borders or impose travel restrictions, but to be vigilant. 

U.N. Secretary-General Ban Ki-moon echoed similar comments, but said the world must be watchful because it is not known what will happen in the coming months.  Mr. Ban said he will convene a meeting next Monday of the U.N.'s influenza steering committee to determine what he called "our immediate next steps."

The World Health Organization says declaring the pandemic will likely get governments to spend more money to contain the outbreak.

The United States has recorded the most cases of the swine flu, with more than 13,000, although Mexico has the most deaths, which currently stand at more than 100. 

The WHO says 144 people have died from the virus.

The last time the WHO declared a pandemic was in 1968, following the outbreak of the Hong Kong flu, which killed at least one million people.

Some information for this report was provided by AP and Reuters