The European Union executive will check whether member states are ready to fight a human pandemic sparked by bird flu, putting pressure on eight EU countries that have failed to prepare an action plan.

Health experts fear the bird flu virus that killed at least 42 people in Asia last year could mutate in a strain easily transmitted in humans, causing a pandemic in which millions could die.

“It is a danger and we have to prepare for it…a pandemic is very likely,” said European Commission health spokesman Philip Tod on Thursday.

“It could happen at any time…the difficulty is it’s a moving target…it could be in a few months or it could be a few years.”

Eight EU states have no preparedness plan in place for an influenza pandemic, while the other 17 need to update their measures, he added, declining to name the countries.

The European Commission will carry out an exercise to test the 25-nation bloc’s readiness in the second half of this year but Tod gave no further details.

Health experts from 52 European nations, including the EU 25, met in Luxembourg to determine the state of preparedness for a flu pandemic, and ways to improve readiness.

An effective vaccination system is one key to fighting a pandemic. Governments have held talks with the pharmaceutical industry, looking into a possible public-private partnership to develop vaccine.

It normally takes at least six to nine months to develop and approve a vaccine, and health officials would like to reduce that to one or two months if possible, according to Tod.

Stockpiling antiviral medications would help, he added. If governments have enough antivirals to treat 25 percent of the population, they will keep a country’s frontline services running, including healthcare workers and other vital sectors.

Antivirals lessen the effects of the disease but do not cure it. The cost of such medication is high. Britain this week said it was buying 14.6 million courses of an antiviral drug at a cost of about $384 million.

Every year 100 million people are affected by influenza in Europe, Japan and the United, according to the European Commission. Influenza kills between 500,000 and 1 million people a year globally.