GlaxoSmithKline Plc, Europe's largest drugmaker, gained European Union approval for its pre-pandemic flu vaccine, Prepandrix. This vaccine is meant to prevent the deadly H5N1 virus.

Prepandrix should be administrated before or in the early stages of a flu pandemic. It determines an immune response to the H5N1 strain of bird flu.

“This is a vaccine that can be produced in advance of a pandemic, that can be stockpiled ahead of a pandemic, which really allows governments to be ready in the event of a pandemic,'' said Emmanuel Hanon, director and vice president of the influenza vaccine franchise at Glaxo's GSK Biologicals in Rixensart, Belgium, in a statement.

This measure was expected, as specialists were and still are afraid that bird flu can cause widespread infections, threatening millions of people. Among governments that have already approved the shot are those of the U.S., Switzerland and Finland. Officials are struggling to prepare for an eventual epidemic caused by the fatal strain of bird flu that has spread across Asia to Africa, the Middle East and Europe since 2003.

The H5N1 virus usually affects birds. It can contaminate people who have physical contact with infected birds. There wasn’t found any evidence of human-to-human transmission so far. However, experts fear that it may mutate into a strain capable of spreading through humans. This explains the necessity of having at disposal vaccines which prevent it.

The permission granted by the European Commission follows the recommendation by the European Medicines Agency in February.