GENEVA: The global H1N1 flu epidemic is still in its early stages, even though reports of more than 100,000 infections in England alone last week are plausible, the World Health Organization's (WHO) flu chief said on Friday.

Keiji Fukuda, WHO's assistant director-general for health security and environment, said given the size of the world's population, the new H1N1 virus is likely to spread for some time.

WHO earlier estimated that as many as 2 billion people could become infected over the next two years.