The World Health Organisation has issued reassurances that swine flu remains stable and has shown no signs of mixing with other influenza viruses.
Some health officials have raised concerns that if H1N1, combined with the much deadlier H5N1 bird flu virus then the pandemic could claim many more lives.
"The virus is still very stable," WHO Director-General Dr Margaret Chan told reporters at a news briefing in Moscow.
"But as we all know the influenza virus is highly unpredictable and has great potential for mutation," Chan said after meeting Russian Health Minister Tatyana Golikova.
Chan's remarks are some of the first comments by the WHO leadership since the United Nations agency declared an influenza pandemic on June 11.
Chan said the viruses needed to be closely monitored to make sure there was no mutation.
"We would need to look at how they are behaving in southern hemisphere countries to see whether the H1N1 and the usual seasonal influenza virus would reassort. So far we have not detected any signal," she said.
"Another important thing we need to monitor is H1N1 and H5N1, which is endemic in some countries in Asia and the Middle East. We would like to see whether there will be any change," she said.
"Again, we did not detect any signal that there is any reassortment."
Chan, a straight-talking native of Hong Kong, said that while much effort was being expended on seeking vaccines, common sense measures could still reduce risks of being infected.
"In prevention and reducing the risk of this infection there is of course a lot of attention given to antivirals and vaccines. But we must not forget there are what we call non pharmaceutical measures which are very effective," she said.
"These are simple measures that each individual can take to protect themselves: don't smoke, get enough rest, eat a balanced diet to support a high level of immunity and frequent washing hands with water and soap."
"If you do unfortunately get infected, please do go to see a doctor."
Reuters rf \NZP