Tuesday October 9 2012
Typhoid is caused by Salmonella typhi bacteria
As many as 700,000 travellers are at risk of typhoid fever because of ‘dud batches of a vaccine’, The Daily Telegraph reports.
The news is based on a drug alert issued by the UK drug regulator, the Medicines and Healthcare products Regulatory Agency (MHRA). The alert to healthcare professionals advises that 16 batches of the typhoid vaccine, Typhim Vi, are being recalled by the manufacturer. The alert has been issued over concerns about the effectiveness of some batches of the vaccine due to an error in the manufacturing process. There are concerns that some patients vaccinated with Typhim Vi since January 2011 may not be fully protected against the disease.
The MHRA says that anyone who has received the vaccine during this time that has recently returned from abroad and is feeling unwell should contact their doctor. They say that the Department of Health is working with the manufacturer to help resolve the current supply problems, caused by the batch recall, as soon as possible.
A spokesperson from the MHRA has said that ‘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’.
What is typhoid fever?
Typhoid fever is an infection caused by bacteria (Salmonella typhi) that can spread throughout the body. It is highly contagious, an infected person can transmit the infection when they defecate or, less commonly, when they urinate. If someone else eats food, or drinks water, that has been contaminated with a small amount of infected faeces or urine, they can contract typhoid fever (this is another of the many good reasons to always wash your hands after using the toilet). Due to the way the infection is spread, typhoid fever is most common in parts of the world that have poor levels of sanitation and limited access to clean water, such as South Asia and Africa.
The usual symptoms of typhoid fever are a high temperature and headache alongside gastrointestinal symptoms, such as stomach cramps and nausea. Typhoid is uncommon in England, with around 350 cases occurring each year. Most of these people are thought to have developed the infection while visiting relatives in Bangladesh, India, or Pakistan.
Typhoid fever requires prompt hospital treatment with antibiotics. Without prompt treatment, it can cause serious complications, such as internal bleeding and damage to the bowel, and can be fatal.
An estimated 21 million cases of typhoid fever and 200,000 related deaths occur worldwide each year.
Why is the vaccine being recalled?
In its press release, the MHRA has asked that all remaining stocks of the affected Typhim Vi vaccine batches are quarantined and returned to the original supplier, Sanofi Pasteur MSD.
The recall of 16 batches of the Typhim Vi typhoid vaccine is due to concerns about the effectiveness of the vaccine in some syringes distributed since 7 January 2011, following filling problems in the manufacturing process.
The MHRA say that recent investigations have indicated that some of the syringes in these batches may potentially have antigen levels (the inactivated bacterial particles a person develops antibodies against when they receive the vaccine) which are below the required specification.
They say that not all doses in the batches are affected. However, it is impossible to predict who may have received the affected doses.
This means that some patients who have been vaccinated with Typhim Vi may not be fully protected against the disease.
Are there any safety concerns about the vaccine?
A spokesperson from the MHRA has said that ‘there are no concerns over the safety of this vaccine’. They say that the recall has taken place ‘because the vaccine may not be as effective as it should be’.
Do I need to get revaccinated?
The MHRA have not advised people to get revaccinated. They say that all travellers should be advised of the importance of exercising scrupulous food and water hygiene precautions when visiting areas where typhoid is prevalent.
How accurate is the reporting on this story?
While the general reporting on the story is accurate, claims that 700,000 travellers are at risk of infection are very much based on a worst-case scenario which would require:
- every single dose in the recalled batches of vaccine to be defective, and
- every person receiving a dose of the recalled vaccine to become infected by typhoid
What steps can I take to protect myself when travelling?
Vaccination is recommended for those travelling to parts of the world where typhoid fever is present, particularly for people planning to work or live with local people. Parts of the world that are most affected by typhoid fever are:
- South Asia
- Southeast Asia
- the Middle East
- Central and South America
In England, most people who get typhoid fever have visited India, Pakistan, and Bangladesh, so it is particularly important to get vaccinated if you visit these countries. Some GP surgeries vaccinate against typhoid fever free of charge on the NHS. Alternatively, vaccinations are available from private travel clinics for around £25.
Vaccinations do not provide complete protection against typhoid fever, so it is important to take some basic precautions when travelling in countries where typhoid fever is present. For example:
- don't buy ice cream, ice cubes, or fruit juice from street vendors
- don't eat raw vegetables, peeled fruit, shellfish, or salads
- if drinking bottled water, check that the bottle is properly sealed before you drink the water and reject any bottle that has a damaged seal
Read more about preventing typhoid fever at NHS Choices:
I have received the vaccine, have travelled abroad, and am now feeling ill – what should I do?
The MHRA advises: ‘if you received this vaccine and have recently returned from abroad, and are unwell, you should contact your doctor’.
An MHRA spokesperson said, ‘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’.
While it is relatively unlikely that these types of symptoms are the result of typhoid fever, it is better to err on the side of caution.
When will more vaccine become available?
The MHRA has said that the recall of the batches will result in the Typhim Vi vaccine being out of stock by the end of October 2012. At the time of the press release, the manufacturer, Sanofi Pasteur MSD, is unable to confirm when normal supply of the vaccine will resume. The MHRA says that there is a licensed oral typhoid vaccine available on the UK market, but stocks of this are also limited. The MHRA has said that the Department of Health is working with the manufacturer to help ensure that current supply problems are resolved as soon as possible.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.