Swine flu vaccine offered protection in up to 95 per cent of cases, studies have shown. (CBC)

The vaccine used to contain the recent swine flu pandemic was effective, but health authorities will need to ramp up the speed and volume of production during the next global outbreak, a World Health Organization official said Monday.

The WHO declared last month that the swine flu pandemic that started in June 2009 was over, after it killed about 18,600 people worldwide, far fewer than the worse-case scenarios in which authorities said millions could die.

The widespread use of vaccines was critical in limiting the number of casualties, with studies showing they offered protection in up to 95 per cent of cases, WHO official David Wood said at a news conference on the sidelines of an influenza conference in Hong Kong.

Some 350 million doses of the vaccine were administered worldwide, according to WHO figures.

"That gives us considerable hope for the future, for the future pandemics, that the technologies that we have to actually make the vaccines are" effective, said Wood, the quality and safety team co-ordinator for the WHO's immunization and vaccines department.

But while vaccines became available six months after the H1N1 virus strain behind the pandemic was identified in April 2009, that was still too late for some countries, he said. In the case of the U.S., vaccination started on Oct. 5, 2009 — weeks after a second wave of cases hit as schools resumed, U.S. Centers for Disease Control and Prevention flu expert Nancy Cox told reporters.

The WHO is studying ways to make vaccines more quickly, Wood said without offering specifics, adding that technological breakthroughs will also speed up the process.

"In the short term, we'll be able to make some gains of weeks that Nancy was talking about that can make all the difference. In the longer term, we may even have these new technologies that shorten our lag more significantly, so I'm quite optimistic," Wood said.

The WHO official also said the global healthy body is working on increasing global production capacity beyond the centres of Europe, America and China, targeting countries like India, Indonesia, Thailand, Brazil and Mexico.

The WHO was accused by some of hyping the pandemic, prompting excessive buying of vaccines and antiviral drugs that enriched drug companies. Asked about such accusations, Wood said the organization only advised countries to vaccinate high-risk groups, like health-care workers and pregnant women.

"I believe that the recommendations that came from the organization were proportionate to the risks that we had at the time," he said.