MEXICO CITY - Policy makers from 50 countries are to gather in Mexico on Thursday to discuss their response to this year's swine flu outbreak, as South America continues to be hit by new cases.

Experts and ministers will gather in the Caribbean beach resort of Cancun for a two-day meeting aimed at gleaning lessons from the crisis, according to Margaret Chan, Secretary General of the World Health Organization (WHO).

The A(H1N1) pandemic has so far killed 332 people worldwide and infected 77,201, the WHO said on Wednesday.

The meeting comes amid clamors to produce an effective vaccine, as the virus spreads in the southern hemisphere - currently in the midst of its winter flu season.

But the meeting is expected to address concerns about whether underdeveloped countries will be able to afford them.

'It is urgent to guarantee, on one hand, that all developing countries have access to an effective vaccine when it is available and, of course, to guarantee adequate treatment to combat this disease,' the leaders of Mexico and Chile said last week.

Outside North American countries, which have been hit hardest by the virus, Chile and Argentina have been deeply affected, reporting dozens of deaths with the number of cases still rising.