Experts say it is difficult to say at the moment. In Mexico infected people have died, while all have recovered in other countries. There are reports that symptoms of infected people outside Mexico are milder, compared to some cases inside Mexico.
Antivirals, such as Tamiflu, have been shown to be very effective in treating patients infected with swine flu. Most developed countries have large stocks of these antivirals. The UK, for example, has enough antivirals to treat 35 million people - over half the country's total population. Prime Minister Gordon Brown has announced the stockpile will increase so that 50 million people can be treated.
Why have people died of swine flu in Mexico but not in other countries?Nobody is sure. Any of these factors could play a part:
- Mexicans who died may have sought treatment at a much later stage, compared to those in other countries.
- ALL the other countries so far are highly developed industrialized countries.
- General living conditions and nutritional standards of those who died in Mexico may have been lower, compared with those who survived in Mexico and abroad.
- The possibility that there may be two viruses circulating - a mild one and a more virulent one - has not been discounted yet.