Work has started on building a 200 million-dose stockpile of smallpox vaccines but it could take up to three years to complete, World Health Organisation (WHO) officials said on Wednesday.

The Group of Seven industrialised nations agreed last month to set up a global “vaccine bank” in case of a germ attack by terrorists.

The WHO will double its emergency reserve of smallpox vaccines to 5 million doses, while individual member countries will assemble the rest.

“It is clear that we will have some stocks in a few months, but it would take two to three years to set up the whole stockpile,” Daniel Lavanchy, smallpox project leader at the WHO’s alert and response office, told AMN Health.

Smallpox, a highly contagious disease with no cure, was declared wiped out in 1979. But there are fears militant groups, such as al Qaeda, could get hold of the virus.

Several hundred thousand doses, along with needles for administering the vaccine, are expected to be delivered to the Geneva-based WHO in the next few months.

“We are progressing,” Lavanchy said.

Brazil and India said at a meeting of the WHO executive board on Wednesday that they could help manufacture the vaccines as long as they got financial assistance.

“Having such a (vaccine) reserve could also serve as a global deterrent against use of smallpox virus in a biological attack,” the WHO said in a report to the meeting.

Smallpox is fatal in up to 30 percent of cases.

Health ministers from the G7 - Britain, Canada, France, Germany, Italy, Japan and the United States - also agreed last month to set up a bioterrorism crisis centre to marshal a global response to germ warfare attacks.

At the time, the United States earmarked 80 million doses of smallpox vaccine for the WHO-run bank. Britain, France, Germany and Canada have also made pledges.

“Developed countries are… concerned that other countries don’t have the means to protect their populations and stem an epidemic,” Lavanchy said.