Pacific island nations are being warned that they are more vulnerable to swine flu than other countries.
Health authorities in Samoa are monitoring the flu symptoms of three people who arrived in the country from the United States but no case has been confirmed in any Pacific Island country.
But the South Pacific WHO's Dr Jacob Kool says island nations are very vulnerable to large outbreaks.
"They have only a limited stretch of their health care systems and a limited stretch of their essential services like safe water, electricity, security and all that. We know that in the 1918 Spanish Flu pandemic the most severely affected countries were actually in the Pacific and some of them had quite a high mortality."