WHO assures swine flu has not mutated,vaccines work very well

“The virus can mutate any time. But from April to now,we can see from the data given to us by laboratories worldwide that the virus is still very similar (to the previous state),” Chan told reporters.

Ideally,3 billion doses of vaccines can be produced worldwide annually,she said,noting that China had already begun to vaccinate people. She said the Hong Kong government could relax its measures against a swine flu outbreak.

Chan said that only high-risk patients such as the elderly,the obese and those with underlying illnesses would be severely affected by the disease.