Deaths not linked to H1N1 vaccines: WHO

About 40 people have died after being inoculated against H1N1 pandemic flu, but investigations so far show the fatalities were not caused by the vaccine, the World Health Organisation said on Thursday.

The U.N. agency reaffirmed that the pandemic vaccine was safe and voiced concern that some pregnant women and others at risk were shunning it because of a fear of side effects.

"No new safety issue has been identified from reports issued to date ... Reporting so far reconfirms that the pandemic flu vaccine is as safe as the seasonal flu vaccine," Marie-Paule Kieny, WHO's top vaccine expert, told a telephone conference.

Governments have so far reported that 65 million vaccine doses have been administered against H1N1, known as swine flu, in 16 countries, but the true figure is probably higher since immunisation campaigns are under way in 40 countries, she said.

Side effects commonly reported include swelling and redness or pain at the injection site, although some had fever or headache, and all symptoms usually disappear after 48 hours.

A "small number of deaths" had been reported, she said, and a WHO spokeswoman later put the figure at 41 in six countries.

"Although some investigations are still ongoing, the results of the completed investigations reported to WHO have ruled out that the pandemic vaccine is the cause of death," Kieny said.

Fewer than a dozen suspected cases of Guillain-Barre syndrome have been reported following pandemic vaccination, she said. "Only a few of this Guillain-Barre may be linked to the pandemic vaccine....and patients have recovered," she added.

The rare neurological condition was linked to a 1976 U.S. swine flu vaccination campaign. Although no case of Guillain-Barre syndrome was ever linked to the vaccine, a belief that the vaccine was worse than the illness remains widespread.

"NO SIGNIFICANT DIFFERENCE"

GlaxoSmithKline Plc, AstraZeneca Plc, Novartis and Sanofi-Aventis are among about 25 manufacturers producing H1N1 vaccine using different techniques.

"No significant difference in the safety profile between different types of vaccine has been detected," Kieny said.

She denounced conspiracy theories about vaccines circulating on the Internet, saying they were causing "artificial worries".

"We have to reiterate that the vaccines are safe, that the disease in certain people can be severe and can be cause of death," she said.

Novartis said on Tuesday a U.S. clinical study suggested just half a dose of its H1N1 vaccine might be enough to generate a protective immune response.

Kieny said the WHO was aware of reports from other drug makers that half a dose was effective, but cautioned that the studies usually involved limited numbers of people.