A vaccine for swine flu will depend on what happens next

The World Health Organisation (WHO) says as of the 5th of May 2009, 21 countries have now officially reported 1,490 cases of influenza A (H1N1) infection (swine flu).

This includes 822 in Mexico with 29 deaths, 403 in the U.S. with one death, 140 in Canada, 57 in Spain, 27 in the UK, 9 in Germany, 6 in New Zealand, 5 in Italy, 4 each in France and Israel, 2 each in the Republic of Korea and El Salvador and one each in Austria, Hong Kong, Colombia, Costa Rica, Denmark, Ireland, Netherlands, Portugal and Switzerland - there have been no deaths in any of these countries.

Health officials in the U.S. are apparently working with vaccine makers to accelerate the production of the seasonal flu vaccine and making preparations for the development of an influenza A H1N1 vaccine.

Both the WHO and the U.S. Centers for Disease Control and Prevention (CDC) say it is too early to make a final decision regarding the manufacture of a H1N1 vaccine, but because the production of an effective flu vaccine is a lengthy process and can take between 4 to 6 months, steps need to be taken now.

The virus has to first be germinated in fertilized chicken eggs and scientists say the manufacture of the seasonal flu vaccine for the northern hemisphere is already under way.

Vaccine experts suggest developing a separate vaccine for the H1N1 virus could be the best approach providing enough eggs are available and this is not expected to be a problem.

The decision to make a vaccine for this new H1N1 virus and then use it will depend to a large extent on what happens in the next six months and how the new virus affects people in the southern hemisphere, where the flu season is just beginning - if it only causes mild disease, a vaccine would not need to be deployed.

The WHO says while there is much greater vaccine capacity than there was few years ago, there is still not enough to make vaccine for the entire world's population for influenza and whether adjuvants - compounds that stimulate the immune system and help make vaccines more effective - could be added to make the vaccines stretch farther, remains a question.

A woman from Texas has become the first U.S. resident believed to have died from swine flu and the second confirmed swine flu death outside Mexico - the American woman in her 30's was living near the border with Mexico - she died earlier this week but had apparently been suffering from "chronic underlying health conditions".

Officials say there have been 61 confirmed cases of H1N1 flu reported in Texas, after Mexico, the U.S. has had the greatest number of laboratory-confirmed infections.

Experts say the sudden jump in the number of cases being confirmed does not reflect increased transmission but more stringent testing and monitoring and 'catching up' on the situation.

The WHO and the CDC say however that the virus can be expected to continue to spread in the United States and elsewhere in the world, and more deaths are likely to follow.

The WHO has urged nations to remain vigilant in spite of the apparently relatively mild nature of swine flu, saying a global pandemic remains a threat and the number of infections has continued to grow worldwide.

While the WHO says it is common sense for people who are ill to delay international travel and for people developing symptoms following international travel to seek medical attention if they develop any symptoms of influenza-like illness, no restriction of regular travel or closure of borders has been advised.

The WHO continues to emphasise that there is no risk of infection from the virus from consumption of well-cooked pork and pork products and advises everyone to maintain good hygiene by washing hands thoroughly with soap and water on a regular basis.