HAVANA, Oct. 27 (Xinhua) -- Visiting Director-General of the World Health Organization (WHO) Margaret Chan said Tuesday that the A/H1N1 pandemic would reach its natural end when enough people are immunized.

　　During a conference at the Tropical Medicine Institute Pedro Kouri in Havana, Chan said more vaccines against the A/H1N1 flu would be distributed in more than 100 developing countries, including Cuba, in November.

　　Chan, who arrived in Cuba on Oct. 24, said vaccines against the flu were ready in less than six months because of international cooperation and the WHO's call for world solidarity.

　　The WHO considered this pandemic "moderate," despite the virus having spread at an exceptional speed, she said, adding that "the causal agent has not mutated" and its resistance to antiviral drugs was "very low."