From the Guidelines
Travel to areas with increased risk of exposure to Salmonella Typhi is the primary risk factor for typhoid infection, and vaccination is recommended for individuals traveling to these areas. When considering the risk factors for typhoid infection, it is essential to understand the modes of transmission and the populations at highest risk. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea 1, typhoid vaccination is recommended for travelers to areas where there is increased risk for exposure to Salmonella Typhi. Some key points to consider regarding typhoid exposure risk factors include:
- Contaminated water and food are common sources of Salmonella Typhi infection
- Poor sanitation and hygiene practices increase the risk of transmission
- Travel to endemic areas, such as certain parts of Asia and Africa, is a significant risk factor
- Vaccination is available and recommended for individuals traveling to high-risk areas, with two licensed vaccines in the United States offering 50%–80% protection 1 It is crucial to note that typhoid vaccines do not offer protection against Salmonella Paratyphi A, B, or C infection, highlighting the need for continued vigilance and adherence to proper hygiene and sanitation practices, even for vaccinated individuals. Understanding these risk factors is essential for prevention efforts, particularly in endemic areas where contaminated water, poor sanitation, and food handling practices are common.
From the Research
Exposure Risk Factors for Typhoid Infection
The following are exposure risk factors for Typhoid (Salmonella Typhi) infection:
- Age: increasing age is associated with severe typhoid disease 2
- Sex: male sex is independently associated with severe disease 2
- Duration of illness: longer duration of illness prior to admission is associated with severe disease 2
- Infection with an antimicrobial resistant organism: infection with an organism exhibiting intermediate susceptibility to ciprofloxacin is independently associated with severe disease 2
- Household hygiene: poor household hygiene is a risk factor for typhoid infection 3, 4
- Food exposures: eating food out in food stalls or restaurants is a risk factor for typhoid infection 3, 4
- Water and sanitation: lack of access to clean water and sanitation is a risk factor for typhoid infection 3
- Hand washing: poor hand washing habits, including not washing hands with soap, are risk factors for typhoid infection 4, 5
- Delay in seeking treatment: delay in seeking treatment increases the risk of typhoid intestinal perforation (TIP) 6
Behavioral Risk Factors
Behavioral risk factors for typhoid infection include:
- Not washing hands at critical moments of the day 4
- Not washing hands with soap 4
- Eating food out in food stalls or restaurants 4
- Poor household hygiene 3, 4
Environmental Risk Factors
Environmental risk factors for typhoid infection include: