Approximately 11 to 20 million people are affected by typhoid fever around the world every year and the disease results in more than 160,000 deaths worldwide.
Singapore is an industrialised country which has good sanitation facilities and hygiene, so it is largely free of the disease. However, if you are travelling to at-risk areas, you have to take precautions.
Sub-Saharan Africa, India, South America and South Asia are areas which have a risk of transmission of the disease, so you should consider a typhoid vaccine to avoid getting infected due to poor sanitation and the paucity of clean drinking water.
The Typhoid Vaccine
There are two types of vaccines for typhoid. One is an inactivated vaccine that is typically administered as an injection or intravenously for hospitalised patients. The other is an attenuated (weakened), active form of the vaccine which is given via the mouth (orally).
- When to get the vaccine: The inactivated typhoid vaccine should be given at least 2 weeks before travel to a high-risk country and should be topped up with booster doses every two years. The active typhoid vaccine should be given on day 1, day 3, day 5 and day 7. The last dose should be given at least one week before travel. Booster oral doses are recommended every five years to reduce risks of infection. The oral vaccination should be given three days after antibiotic treatments (especially sulpha-based antibiotics) and should not be administered to children less than 6 years of age.
- Who should not get the vaccine? The jabs (inactive vaccine) should not be given to children below the age of two. Both kinds of vaccines should not be taken by those who have suffered from moderate to severe typhoid infection in the recent past. The typhoid vaccine should also not be taken by those who are allergic or react to one or more components. In such cases, please ask the medical practitioner for alternatives.
Side-effects of the typhoid vaccine
Though they are rare, some may experience side-effects after getting the two types of typhoid vaccines.
Side-effects may include:
- Nausea, diarrhoea and vomiting
- Breathing difficulties
- Swelling of face, throat, lips
- Redness or swelling at the site of the injection
How effective is the typhoid vaccine?
The injectable typhoid vaccination starts providing protection roughly 7 days after administration. The efficacy reduces to 72% after a year and to 50% after 3 years. It’s also very important to note that although typhoid vaccine is very effective, it does not guarantee 100% protection in the event of working in unsanitary and poor hygiene conditions. Care with food and drink should remain a priority throughout your travel. Once you receive the vaccination, the clinic will issue you with a medical certificate/medical stamp.
It’s also advisable to inform your doctor about all the vaccines that you have received in the past, the antibiotics that you have been prescribed, allergies and any other preexisting medical conditions. Your medical practitioner will decide on the most suitable type of typhoid vaccine to suit your requirement.
What is typhoid?
Typhoid fever (known as ‘typhoid’ in short) is an infection that is caused due to a specific strain of bacterium known as ‘salmonella typhi’. Those suffering from typhoid infection carry salmonella typhi in their intestinal tract or blood stream. The bacteria can contaminate food and water, thus spreading the infection directly to others.
The origins of typhoid
Although information regarding the exact origins of typhoid fever is uncertain, one-third of Greece’s population is believed to have been eliminated around 430 BC due to the outbreak of what is now suspected to be typhoid fever.
Typhoid is not a common disease in Singapore due to the high standards of hygiene and sanitation in the country. After the discovery of the vaccination, the incidents of typhoid fever steadily decreased in Singapore and around the world.
The reduction of outbreaks can also be attributed to improvements in sanitation and hygiene and chlorination of water. Today, typhoid fever is rare among industrialised nations such as Singapore and make up only roughly five cases in a million per year.
How is typhoid spread?
The bacteria that causes the disease, salmonella typhi usually enters the body through the mouth. This happens when someone consumes contaminated food, water or milk. A human carrier, who may be employed in handling or processing food or water, may trigger further spread of the disease.
In addition, typhoid infection may be spread by flies. The infection thus spreads through what is known as the ‘oral-faecal’ route. The bacteria invade the gallbladder, lymphatic tissue and biliary system and multiply in large numbers.
A human carrier spreads the bacteria by passing infected stools (or in less common cases, infected urine). Any food or water that is infected becomes contaminated with the bacteria. If another person eats or drinks the contaminated food and water, he or she may then become infected with typhoid fever (some people become carriers but may not show symptoms immediately). In fact, a small percentage of people remain carriers all their lives and carry salmonella typhi bacteria in their gall bladders or intestinal tracts.
The typhoid bacterium is known to have a long incubation period – almost as long as one month in some cases. Hence, the individual may be infected earlier but may take time to experience symptoms.
Although one tends to be at higher risk while travelling to affected countries, you can also contract the infection through ingesting raw vegetables, shellfish, imported food products etc. Most people from western nations tend to pick up the infection while travelling and transmit it to others when they return back home.
Children remain at the greatest risk from typhoid fever although they experience milder symptoms compared to adults. The salmonella typhi bacteria only survives in a human habitat; animals do not contract the infection.
Symptoms of Typhoid
Once symptoms of typhoid fever appear, one is likely to experience one or more of the following during early stages:
- Stomach pain
- Diarrhea or constipation
- Loss of appetite
- Rash of flat, rose-coloured spots
During later stages, the symptoms become malevolent and may include delirium, intestinal bleeding and slow heart rate. Intestinal bleeding occurs when the intestine develops perforations and leaks content into the blood.
Patients may feel completely drained or exhausted in what is commonly known as the ‘typhoid state’. Less common but severe symptoms include kidney infections, pneumonia, pancreatitis and meningitis.
Symptoms begin to recede in about three to four weeks and roughly 10% patients may be at risk of relapse after showing initial improvement.
People who do not get treatment can continue to have fever for weeks or months, and can develop complications. Up to a third of those who do not get treatment die from complications of the infection.
Treatment and Prevention
The only way to know for sure if an illness is typhoid fever is to have a sample of blood or stool tested for the bacteria that causes the disease.
Treatment involves administration of antibiotics for 7 to 14 days which may be given orally or through injections. The antibiotics are usually prescribed for twice a day to be eaten an hour before meals. There are several strains of salmonella typhi and the doctor will prescribe an antibiotic based on the type of strain detected in the laboratory sample. Some typhoid bacteria are known to be extremely resistant to antibiotics.
To prevent the spread of infection, you should also ensure that you wash your hands with warm soap and water at frequent intervals (especially after using the restroom and before eating). While most people are treated at home, those with severe symptoms should be admitted to hospital for treatment. You should also take adequate rest, eat plenty of fruits and vegetables and drink a lot of water.
Do I need a typhoid vaccine?
Although the bacterium Salmonella Typhi is present worldwide, the risk of typhoid fever infection is higher in developing countries, so the vaccine is recommended for people planning a trip to one of the following regions:
- Southeast Asia
- Central America
- South America
- The Caribbean
Even after receiving the vaccine, people at a destination where typhoid fever is endemic should still take precautions to avoid infection, such as drinking only bottled water, avoiding adding ice to their drinks if they are not from a reliable source, eating foods that have been properly cooked, and washing their hands frequently, particularly before handling food.
Should I get typhoid vaccine boosters?
MOH recommends that you get a booster shot every three years to ensure maximum protection from the disease.