Caught in the flu

Nations across the world stand divided on variations of the vaccination regimen for swine flu.

A World Health Organization advisory panel were asked to answer a question dividing governments from the US to Japan: whether one or two doses of swine flu vaccine are needed to fight the pandemic virus.

Initial results of tests on pandemic vaccines produced by companies including Sanofi-Aventis SA, the world’s largest maker of flu shots, suggested one inoculation protects most adults. The US and Australia have begun a mass immunisation programme based on a single-dose regimen. Japan and the European Union aren’t convinced and are calling for two shots.

 

The number of shots given will determine how many people can be immunised before infections peak, especially in poor nations which may receive only 10 per cent of global supply. In making their recommendation, WHO’s so-called strategic advisory group of experts on immunisation will need to balance optimal protection for an individual against sufficient protection for an entire population, said Albert Osterhaus, head of virology at Erasmus University Medical Center in Rotterdam.

“There is a definitely an issue of equitable distribution,” said Osterhaus, who was invited to participate in the discussion, in an interview yesterday.

About 3 billion doses of the pandemic vaccine may be produced within 12 months, the WHO estimated in September, not enough to cover a world population of 6.8 billion people in which “virtually everyone is susceptible to infection by a new and readily contagious virus”.

At least 1.5 billion doses have been accounted for by developed nations, according to WHO. France contracted to buy 94 million doses for its 64 million people. The UK, with 61 million people, ordered 90 million.

‘SAFE AND SOUND’
“There are extra options in Europe which might not be the case in other countries,” said John Oxford, professor of virology at Queen Mary’s School of Medicine and Dentistry in London, in an interview yesterday. “You are playing ‘safe and sound’ with two doses.”

Most low-and middle-income nations lack money to compete for an early share of limited doses, Geneva-based WHO said in a September 24 statement, adding that vaccine supplies in these countries will largely depend on donations from manufacturers and other nations.

Preliminary data from a study on GlaxoSmithKline Plc’s Pandemrix showed 98 per cent of those aged 18 years to 60 years had an immune response indicative of protection after one shot. Tests on the elderly found 87 per cent of those older than 70 had a sufficient immune response after one dose, London-based Glaxo said yesterday.

ANTIBODY LEVELS
The findings are based on antibody levels used to gauge the efficacy of seasonal flu shots, and support results from similar trials in China, the US and Australia.

The WHO panel will probably be swayed by the data and join the US National Institutes of Health and agencies in Australia and China in recommending a single-dose regimen, Oxford said.

“That would relinquish supplies for either countries that have not bothered to prepare themselves — which is quite a lot of them — or haven’t got the wherewithal to do it,” he said. “WHO has to factor in all these political and economic things.”

The discussion on flu vaccine in Geneva is aimed at producing a set of recommendations for WHO Director-General Margaret Chan to consider. Reporters are slated to be briefed on the final outcome on November 6.

Some authorities have already decided.

GLAXO, NOVARTIS
Though data available for Glaxo’s Pandemrix and Novartis AG’s Focetria vaccines indicate that one dose may be sufficient in adults, the information is too limited to allow the European Medicines Agency to recommend the general use of a single shot, the regulator said in a statement last week.

Japan’s health ministry said on October 20 that most of its citizens should get two doses to maximise protection. Healthcare workers should be vaccinated first, followed by pregnant women, people deemed to be at higher risk because of existing conditions like diabetes, and children ages one to six, it said.

Some experts said the decision would limit the amount of vaccine available for children, who won’t be given priority though they are most likely to catch the bug and develop complications.

“If Japan keeps the rule to give a two-shot course to high-risk people, the country won’t have enough vaccine to cover children,” Yoshihiro Kawaoka, a virology professor at the University of Tokyo, told a scientific meeting in the Japanese capital on October 26.

PRIORITY GROUPS
Japan began immunising healthcare workers last month and plans to have vaccine for as many as 77 million people, or 61 percent of its population, by March. Children aged one year to six years will be inoculated starting early December, with the program extended to older children about two weeks later, according to the ministry.

“We need to start a discussion on the priority ranking for vaccination,” said Hitoshi Oshitani, a professor at Tohoku University in Sendai, northern Japan. “In Japan, more children with swine flu are in serious condition compared with other high-risk groups.”

Pandemic vaccines have their greatest impact as a preventive strategy when administered before or near the peak incidence of cases in an outbreak, according to the WHO.