Frequently Asked Questions about Diphtheria
What is diphtheria?
Diphtheria is a rare disease, which is caused by the bacteria called Corynebacterium diphtheriae and Corynebacterium ulcerans. It may affect the throat or nose and sometimes the eyes or the skin. Some diphtheria bacteria are more dangerous than others and can cause serious illness. Only bacteria that produce diphtheria toxin (poison) cause the classical disease we call diphtheria. Diphtheria is contagious and can be passed from person to person through the tiny droplets in sneezes and coughs. It can be spread by close, prolonged contact (for example in the home) or by close face-to-face contact with an infected person.
Who can get diphtheria?
Anyone can get diphtheria, but it is extremely unlikely if you have been fully vaccinated. Diphtheria is more common in some countries with poor vaccine uptake, especially in Africa, South Asia and the former Soviet Union, so it is important to make sure your vaccinations are up to date if you are travelling to these areas. Nearly all UK cases of diphtheria caused by the C. diphtheriae bacteria are imported.
How is the germ spread?
The C. diphtheriae bacteria are spread by being in very close contact over a period of time with someone who has the illness or is a carrier.
The C. ulcerans bacteria can be spread by being in very close contact over a period of time with animals that carry it in their nose or throat or by drinking unpasteurised milk or eating products made from unpasteurised milk.
What are the symptoms of diphtheria?
This depends of where the infection is. The illness may start with a sore throat and fever. There may be a hoarse voice or cough and in severe cases a greyish membrane may develop in the throat obstructing the airway. If the skin is affected there may be an ulcer that does not heal. It is important to seek medical advice and treatment immediately.
How long is a person infectious?
A person is no longer infectious after they have received a full course of treatment, which is usually given in hospital.
How long does it take for the illness to develop?
The illness may develop up to seven days after contact with the bacteria.
How is it diagnosed?
A diagnosis of classical respiratory diphtheria is based on the symptoms, for example, the grey throat membrane and swollen neck. Swabs will be taken from the nose, throat and any skin wounds, cuts or ulcers so that the infection can be confirmed via laboratory tests. Partially immunised people can develop milder symptoms of diphtheria, such as a severe sore throat, and these will only be diagnosed by a laboratory test for the presence of thebacteria.
Should I receive treatment?
You will only receive preventative treatment if you are a close contact of the person who has diphtheria. A close contact is typically someone who has slept in the same household or has had intimate contact with the affected person in the previous week. School classroom contacts and those who share the same room at work are not normally considered to be close contacts. A doctor or nurse will take a swab test from your nose and you will be given a prescription for a course of antibiotics. It is important to finish the whole course of treatment. You will also receive a booster vaccination if required.
I cared for a diphtheria patient in hospital. Should I be treated?
Any health care workers who may have been involved in treating a patient with diphtheria may also require a swab test, antibiotics and immunisation against the infection.
How is diphtheria treated?
Patients with respiratory diphtheria require hospitalisation and treatment with diphtheria antitoxin. They will also be given appropriate antibiotics to eliminate the bacteria. When they have recovered they will be given a dose of diphtheria vaccine as having the disease does not necessarily protect against further infection.
In addition, people who have been in contact with a diphtheria patient will be assessed and may receive preventative antibiotic treatment and booster vaccination.
Diphtheria is a disease that should be prevented, by vaccination, rather than treated, but these methods are effective and can control the infection if the diagnosis is made early. Treatment is always very urgent and should not be delayed.
What is the difference between toxin-producing and non-toxigenic diphtheria bacteria?
Only diphtheria bacteria that produce a substance called a toxin can cause serious illness. Non-toxigenic strains do not produce this toxin.
How easy is it to catch diphtheria?
The most important way to avoid the disease is vaccination. All children in the UK are routinely offered immunisation against diphtheria at two, three and four months old. Booster doses are given before starting school and then again between 16 and 18 years.
Diphtheria is more common in some countries where vaccine uptake is poor, especially in Africa, South Asia and the former Soviet Union, so it is important to make sure your vaccinations are up to date before you travel to these areas.
Why can diphtheria be so serious?
Diphtheria is a serious disease in those who have not been immunised and usually begins with a sore throat and fever that can quickly develop to cause severe problems with breathing.
The toxin produced by the bacteria can damage the heart and nervous system, and in severe cases it can kill.
When was the last death from diphtheria in someone who acquired the infection indigenously or elsewhere?
The last death from indigenous diphtheria (i.e. not infected abroad) caused by C diphtheriae was in 1982, in a three-year-old child who had not been immunised.
In 1994 a 14-year-old boy died after contracting the disease in Pakistan. His vaccination status was unknown, but it is unlikely that he had been immunised.
There have been two recent deaths, one in 2000 and one in 2006, caused by the C ulcerans bacteria. Both were elderly unvaccinated women.
When was the last case of diphtheria – acquired indigenously or acquired elsewhere?
Since 1986 there have been eight cases of respiratory diphtheria caused by the C. diphtheriae bacteria, with the last being in 1997. All these cases had recently returned to the UK from endemic areas.
Does the vaccine offer good protection against diphtheria?
Yes. Diphtheria vaccine is given as part of a combined diphtheria, tetanus, pertussis, Hib (Haemophilus influenzae type b) and polio vaccine, and offers very effective protection against all these diseases.
If I have been fully immunised can I still get diphtheria?
No, the vaccine protects you against the diphtheria toxin. However, immunisation does not prevent you from carrying the bacteria.
Most cases occur in people who are unvaccinated or inadequately immunised.
How effective is diphtheria vaccine against the toxins produced by these germs?
The vaccine offers very good protection against the toxins produced by the diphtheria bacteria.
What is the normal incidence of diphtheria within the UK?
Diphtheria is extremely rare in the UK due to high uptake of an effective vaccine against the infection. Since 1986 there have only been eight cases of respiratory diphtheria caused by C diphtheriae (all these cases had travelled to areas where the infection is more common) and seven cases of respiratory diphtheria caused by C ulcerans.
What is the uptake of the diphtheria vaccine in the UK?
In 2006-2007, diphtheria vaccine coverage in the UK for two-year-old children was 94 per cent.
Last reviewed: 10 June 2008