Orders of Zostavax in England are being capped at just five doses due to delays in the supply of the vaccine to the UK, public health officials said. Supply levels are not expected to return to normal until October at the earliest.
Practices had been advised to administer the vaccine to 70- and 79-year-olds at annual flu jab clinics, currently being organised.
Officials said the supply issue should not affect overall vaccination plans because patients can be given the jab later in the year.
But RCGP immunisation lead Dr George Kassianos said a shortage of doses would hit surgeries' vaccination clinics.
He said: 'We have written to all our patients eligible to receive Zostavax to come to the first open Saturday, which is imminent, to have their influenza and shingles vaccines. What do we do now? How can GPs manage campaigns with hardly any vaccine? Which five patients in a large practice should receive the Zostavax first?'
Dr Kassianos added: 'This issue is interfering with the ability of the practices to deliver the immunisation campaign the DH has asked GPs to carry out.'
Adults aged 70 and 79 are being offered vaccination to protect against shingles in a nationwide campaign that began on 1 September. The Zostavax vaccine was chosen for the programme following advice from the Joint Committee on Vaccination and Immunisation (JCVI).
Supply issues 'for years'
Plans to introduce a national programme in 2010 were delayed for years due to supply problems with Zostavax. The vaccine has limited availability because the virus it uses is complicated to grow on the scale needed for vaccine production.
In June 2012, the JCVI said there may be sufficient supply of the shingles vaccine to launch a vaccination programme in 2013, so long as the vaccine could be purchased at a cost-effective price.
The DH decided to press ahead with rolling out a national programme for 70-year-olds this autumn, as well as a catch-up campaign for 79-year-olds. It holds a central stockpile that practices can order from using the ImmForm website.
In an update bulletin, officials at Public Health England said: 'Based on assurances of continuity of supply from the manufacturer - Sanofi Pasteur MSD - national distribution of the Zostavax vaccine began on 1 August 2013.
'However, due to a current temporary delay with the supply of the vaccine into the UK, customer orders in England are currently being capped at five doses per order. This situation will remain fluid and the order quantity may vary until supply can be resumed fully, which is unlikely to be before October.'
They added: 'A large quantity of vaccine has already been distributed throughout the UK to start the programme. We do not expect this temporary supply issue to affect the overall programme to immunise all 70- and 79-year-olds who request the vaccination over the forthcoming year.'
A spokesman for Sanofi Pasteur MSD confirmed the supply problems. 'We are required to complete a number of tests before a vaccine can be distributed in the EU. Unfortunately, we regret that this testing is taking longer than anticipated,' he said.
'The company confirms that production of shingles vaccine is on-going and doses committed for year one of the national shingles immunisation programme will be delivered.'
The company will issue updates on the supply situation as it develops, but the programme 'will not be affected' by the delays, the spokesman said.
GPs and practice staff should check the ImmForm website for the latest on vaccine availability.