WHO emphasizes safety of flu vaccine

The World Health Organization moved to reassure the public about the safety of pandemic flu vaccines on Thursday while revealing that the first vaccines should be approved and ready for use in some countries from September.

"The public needs to be reassured that regulatory procedures in place for the licensing of pandemic vaccines, including procedures for expediting regulatory approval, are rigorous and do not compromise safety or quality controls," said the U.N. health agency on its website.

Adverse effects rare

While some serious adverse effects had been reported over the 60 years that flu vaccines have been used "these have been rare," it said.

Nonetheless, the WHO said "special safety issues will inevitably arise during a pandemic" because of the massive scale on which a vaccine would be administered.

"For example, adverse events too rare to show up even in a large clinical trial may become apparent when very large numbers of people receive a pandemic vaccine," the WHO added.

Countries have been ordering tens of millions of doses of vaccine for the A(H1N1) virus for mass vaccination campaigns, while clinical trials are usually carried out on thousands of volunteers.

The trials have began in Australia, Britain, China, Germany and the United States, WHO's director of vaccine research Marie-Paule Kieny said.

"We expect more clinical trials to start in the days to come," she said, adding that first results of the trials should be collected in September.

If regulators were to approve the vaccine "in September, then it is possible that some countries (will) start vaccinating in September," said Kieny.

The public needs to be reassured that regulatory procedures in place for the licensing of pandemic vaccines, including procedures for expediting regulatory approval, are rigorous and do not compromise safety or quality controls

WHO

Yields improving

Kieny also said that manufacturers initially reported that vaccine virus strains were generating "disappointing" yields but that the yields were improving.

One of the virus strains used by vaccine makers now seems to be yielding the same amount as seasonal vaccine, while early indications were that pandemic H1N1 yields might be only 30 percent of normal.

"I don't want to say too early that the question has been resolved but it really seems that we have found a way to go round this problem," Kieny told reporters. "We are on track in development."

The H1N1 flu outbreak, declared a pandemic on June 11, has spread around the world and could eventually affect 2 billion people, according to WHO estimates.

At present, patients with mild symptoms generally do not need any medicines to recover, and WHO has stressed hospital visits are not necessary unless those infected with flu have certain warning signs.

These include long-lasting high fever in adults and a lack of alertness in children. Pregnant women and people with health problems including diabetes are also vulnerable to more severe effects from the flu.

I don't want to say too early that the question has been resolved but it really seems that we have found a way to go round this problem," Kieny told reporters

WHO director of vaccine research Marie-Paule Kieny