The national stockpile of 30m swine flu vaccine doses will be available for the coming flu season, when swine flu is expected to circulate.
But this stockpile expires in October 2011, the DoH told GP, meaning any doses not administered this winter will be unusable by next year’s flu season.
Last week, DoH accounts showed how the department lost over £200m on unused monovalent swine flu vaccine and antivirals in 2009/10.
The department wrote off the loss but said the vaccine would be retained for future use.
However, the impending expiry means much of this stockpile will go unused, as this year's trivalent seasonal flu jab contains swine flu antigens. This will be given to most at-risk groups instead.
With a global surplus of vaccine at present, it is also unlikely the DoH will be able to sell off unused vaccine before the 2011 deadline.
A DoH spokeswoman said: ‘Any requests from other governments for supplies from our reserve of vaccine would be considered at the time, taking account of the needs for a stockpile for the UK population.’
The DoH has 20m doses stored centrally, while general practices hold an estimated 10m doses.
However, the monovalent vaccine is unlikely to be widely used in this year’s flu season, leaving millions of doses unneeded.
From September, the monovalent vaccine will only be give to at-risk children between six months and five years, and immunosuppressed people, who haven’t yet received the monovalent vaccine.
The UK’s stock of antivirals has a longer shelf life. The NHS currently holds 30m treatment courses of Tamiflu. Some of this will expire next year, with other stock usable until 2016. The UK also has a stockpile of Relenza.
The DoH said GPs can order any additional swine flu vaccine doses required for the coming flu season through PCTs.
The department also released guidance on the efficient use of vaccines, including an update on VESPA (Vaccine Efficiency Savings Programme Audit).