Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi . It is usually spread through contaminated food or water. After entering the body, Salmonella Typhi bacteria begin to multiply and enter the blood.
Urbanization and climate change may increase the global burden of typhoid fever. In addition, increasing bacterial resistance to antibiotics is contributing to the spread of typhus in communities that lack access to safe drinking water and adequate sanitation.
Salmonella Typhi lives only in the human body. People with typhoid fever carry the bacteria in their blood and intestines. Symptoms include persistent fever, fatigue, headache, nausea, abdominal pain, and constipation or diarrhea. Some patients may develop a rash. Severe cases of the disease can lead to serious complications and even death. At least 30% of patients who do not receive treatment die from complications of the disease. The diagnosis of typhoid fever can be confirmed by a blood test.
Improvements in housing conditions and the introduction of antibiotics led to a sharp decline in typhoid incidence and mortality in industrialized countries. However, this disease remains a challenge for the health care system in many WHO regions (more precisely, in their developing areas): in Africa, the eastern Mediterranean, south-east Asia and the western Pacific.
According to 2019 data, there are 9 million cases of typhoid every year, resulting in about 110,000 deaths per year.
Population groups without access to safe water and adequate sanitation are at increased risk of the disease. Children are the highest risk group.
Typhoid can be treated with antibiotics. Due to the prevalence of antimicrobial resistance in the most affected regions, more complex and expensive treatment options may be used.
Even after symptoms disappear, people can still carry the typhoid bacteria, which can be excreted in their feces and passed on to other people.
It is important that patients undergoing treatment for typhoid take the following measures:
Typhoid spreads in areas with poor sanitation and a lack of safe drinking water. Access to safe water and adequate sanitation, good hygiene by food handlers, and vaccination against typhus are effective measures to prevent the disease.
The typhoid conjugate vaccine, which contains the Vi antigen bound to a carrier protein, is given as a single injection to children aged 6 months and older and adults up to 45 or 65 years of age (depending on the vaccine).
In October 2017, the WHO Strategic Advisory Group of Experts on Immunization (SAGE) recommended that typhoid conjugate vaccine (TCV) be added to routine childhood immunization programs in typhoid-endemic countries. SAGE also called for the vaccine to be given priority to countries with the highest burden of typhoid disease or with high levels of antibiotic resistance to Salmonella Typhi.
Since 2019, the Gavi Vaccine Alliance has been funding the provision of typhoid conjugate vaccine to countries meeting these criteria.
As of March 2023, WHO has prequalified two conjugate vaccines for the prevention of typhoid (commercial names: Typbar TCV and TYPHIBEV) . Unlike other vaccines against typhoid, conjugated vaccines form longer immunity to the disease, and also have higher efficiency (79-85% against 50-80% of previous generation vaccines). Therefore, it is currently recommended to administer only one dose of the conjugate vaccine, which can be used from the age of 6 months. Apart from reducing the burden of typhoid disease in endemic countries and saving human lives, the widespread use of conjugated typhoid vaccines in such countries will reduce the need for antibiotic therapy for typhoid and thus reduce the rate of spread of antibiotic resistance to Salmonella Typhi.
Two other typhoid vaccines have been used for many years in older children and adults at risk, including travelers, and are commercially available. These vaccines do not provide long-lasting immunity (require booster doses) and are not approved for use in children under two years of age:
All persons traveling to endemic areas are at potential risk of contracting typhoid fever, although the risk is generally low in tourist and business centers with high standards of accommodation, sanitation, and food hygiene. Typhoid vaccination should be offered to individuals planning travel to high-risk locations.
It is also important to adhere to the following WHO recommendations when traveling: