Health experts could face a shortage in typhoid fever vaccination stocks after they were forced to recall a batch which is not potent enough.
Travellers have been warned that they may not be fully protected against the potentially fatal disease and have been urged to contact their GPs if they have recently returned from abroad and are feeling unwell.
French manufacturer Sanofi Pasteur has recalled 16 batches of its jab Typhim Vi because of concerns about the effectiveness of the vaccine.
The Medicines and Healthcare products Regulatory Agency (MHRA) said that all vaccines distributed from January 7 last year are to be returned.
Some patients who have had the vaccine since then may not be fully protected against the disease, the MHRA said.
Typhim Vi represents 88% of the UK market of typhoid fever vaccination.
In England, more than half a million people receive the jab every year.
But the MHRA said the vaccine is still available and the Department of Health said it is working with manufacturers to help resolve supply problems.
Ian Holloway, head of defective medicines report centre at the MHRA, said: "There are no concerns over the safety of this vaccine but the recall has taken place because the vaccine may not be as effective as it should be.
"Anyone who has been to a typhoid region of the world and has a fever, abdominal pain and vomiting should contact a healthcare professional. They can also give them information and advice about minimising the risk of getting typhoid."
Typhoid fever is very contagious and can be fatal unless treated with antibiotics. Patients usually present with a fever, headache, stomach pains, loss of appetite, nausea and, in some cases, a rash.
The disease, which varies in severity, can last several weeks and convalescence takes some time. It is acquired through the ingestion of contaminated food and water. The bacteria are passed on through the faeces and urine of infected people.
It is most common in areas of poor sanitation, particularly south Asia and south-east Asia.
The UK has about 350 cases of typhoid fever each year, which are almost exclusively acquired abroad.
The Department of Health holds a strategic reserve of about 80,000 doses as an insurance policy in case of problems with supply and manufacturers have no vaccine supplies available to order.
A Department of Health spokeswoman said: "Typhoid is rare in this country and is usually associated with travel to countries where sanitation is inadequate.
"The vaccine is still available and we are working with manufacturers to help ensure that current supply problems are resolved as soon as possible.
"People who have recently been immunised should seek medical advice about precautions to take whilst abroad to minimise the risk of infection, in case the vaccine has not provided full protection."