Licensed swine flu vaccine could take more time says WHO

A fully licensed swine flu vaccine might not

be available until the end of the year, a top official at

the World Health Organisation said this week in a report that

could affect many countries' vaccination plans.

Countries could use emergency provisions to get the vaccines out quicker if they decide their populations need them, Marie-Paule Kieny, director of WHO's Initiative for Vaccine Research, told a news conference.

The swine flu viruses currently being used to develop a vaccine aren't producing enough of the ingredient needed for the vaccine, and WHO has asked its laboratory network to produce a new set of viruses as soon as possible.

So far, the swine flu viruses being used are only producing about half as much 'yield' to make vaccines as

regular flu viruses.

Last week, WHO reported nearly 95,000 cases of swine flu

worldwide including 429 deaths. Most people who get the virus only experience mild symptoms and don't need

treatment to get better.

In a presentation to WHO's vaccines advisory group, Kieny said a lower-producing vaccine would significantly delay the timeline for vaccines. That could complicate many countries' plans to distribute vaccines by Autumn.

Before countries can start any mass vaccination campaigns, the vaccines need to be vetted by regulatory

authorities for safety issues. That means testing the them in a small number of humans first, which can take weeks or months.

"I think it will be a very significant challenge to have vaccines going into peoples' arms in any meaningful number by September," said Michael Osterholm, director of the Centre for Infectious Diseases Research and Policy at the University of Minnesota.

"At this point, it is still an issue of when will it be available, who will get it, and what will be the dose?"

Kieny said many of those questions remain unanswered at the moment. But she said WHO's vaccine advisory group recommended that health care workers receive the first swine flu shots since they are on the front lines of the global outbreak.

The decision to start vaccinating people against swine flu, which so far remains a mild virus in most people, will ultimately be a gamble, since there will be limited data on any vaccine.

Until millions of people start receiving the shots, experts will not know about rare and potentially dangerous side effects.

The public health community may still be scarred by the USA's disastrous 1976 swine flu vaccination campaign, which was abruptly stopped after hundreds of people reported developing Guillain-Barre syndrome, a paralysing disorder,

after getting the flu vaccine.