A continuing shortage of a yellow fever vaccine in the UK could affect people travelling to the World Cup in Brazil this summer.
The UK manufacturer of yellow fever vaccine - Sanofi Pasteur MSD - reported a shortage caused by production problems last September.
The situation was expected to have been remedied by January but vaccine clinics are still reporting problems and say they have not been told when the issue will be resolved.
The shortage is of single-dose vaccinations. Ten-dose vials are more readily available but must be used within six hours of opening.
Vaccination clinics are offering the yellow fever jab by appointment when 10 people can be vaccinated in one session.
As multi-dose vials are more expensive, they have increased the price of each vaccine.
A spokesperson for Sanofi Pasteur MSD confirmed that there was a continuing shortage of the single-dose yellow fever vaccine: 'This is due to a temporary manufacturing issue. While the solution to the manufacturing delay is on-going, the supply of the yellow fever single-dose presentation has been interrupted.
'At present, I am unable to confirm when stocks of single-dose yellow fever vaccine will be available.
'While our temporary shortage of single-dose yellow fever vaccine continues, travel clinics have access to other sources of yellow fever vaccine.'
The London Travel Clinic said it had a limited supply of the vaccine and advised patients to book an appointment by phone to reserve their vaccine, while The Travel Clinic Ltd. said that their clinics in Cambridge and Ipswich had managed to get sufficient stock of 10 dose vials for now but have had to increase the price of a vaccine to reflect the ‘logistical difficulties and potential financial loss’.