The realisation that one shot of pandemic vaccine, not two, is likely to suffice for most people means governments that placed early orders could have excess stocks while others face a shortage or even a complete lack of vaccine.
The EU executive said it would encourage "a common approach to cross-border sharing and voluntary sale within the EU".
According to the Commission, vaccination remains one of the most effective means of preventing the spread of the pandemic. Solidarity for third countries is also part of the overall capacity-building that the EU executive wants to promote.
Some countries have already included a provision in contracts with manufacturers stating that unused vaccines can be sold to other countries, it added.
"We need to remain vigilant and continue to coordinate our preparations to respond to the pandemic in the months ahead," EU Health Commissioner Androulla Vassiliou said in a statement.
The Commission also proposed an eventual joint procurement mechanism for countries ordering vaccines, since this could lead to economies of scale, although initially the aim will be to bundle together calls for national tenders.
The new H1N1 strain of flu, declared a pandemic on 11 June, could eventually infect two billion people, according to World Health Organisation estimates. But manufacturing capacity constraints mean there will only enough vaccine to protect a fraction of those at risk this year. Still, a few countries that booked early could have a surplus. Britain, for example, ordered enough vaccine to give two doses to its population.
"There is a certain amount of discontent amongst other EU governments about the success of the UK government in locking up the initial supplies through its advance purchase agreements," Robert Dingwall of the University of Nottingham told reporters on Monday.
Leading flu vaccine manufacturers including GlaxoSmithKline, Sanofi-Aventis, Novartis, CSL and Sinovac have all found their H1N1 vaccines give good protection after just one dose, confounding expectations that two shots would be needed.
(EurActiv with Reuters.)
