Last friday, the World Health Organization said that the global spread of H1N1 flu virus or swine flu could speed up in coming months. Governments must boost preparations due to this condition.

WHO's Western Pacific director, Shin Young-soo, explained that there will soon be a period of further global spread of the swine virus, and most countries may see this flu cases double every three to four days for several months until it reached peak transmission.

"At a certain point, there will seem to be an explosion in case numbers, " he said. "It is certain there will be more cases and more deaths."

Governments must act quickly to educate the public, prepare their health systems to care for severe cases and protect those deemed more vulnerable to prevent unnecessary deaths, he said.

"We only have a short time period to reach the state of preparedness deemed necessary," Shin said. "Communities must be aware before a pandemic strikes as to what they can do to reduce the spread of the virus, and how to obtain early treatment of severe cases."

Pregnant women are in higher risk of complications, and the virus also has more severe effects on people with underlying medical conditions such as asthma, cardiovascular disease, diabetes, autoimmune disorders and diabetes, WHO chief Margaret Chan said in a video address.

Health officials and drug makers, meanwhile, are looking into ways to speed up production of a vaccine before the northern hemisphere enters its flu season in coming months. Estimates for when a vaccine will be available range from September to December.

WHO has stressed that most cases of swine flu are mild and require no treatment, but the fear is that a rash of new infections could overwhelm hospitals and health authorities, especially in poorer countries.

WHO has declared swine flu as a pandemic disease. Through last week, this virus has killed about 1.800 peoples worldwide. Swine flu is continuing to spread during this summer in the northern hemisphere. Normally, this virus disappear in warm weather. But now, swine flu is proving to be resilient.