Ritonavir Powder Packets and Typhoid Vaccine

• Generic Name: ritonavir
• Dosage Forms: n.a.
• Other Brand Names: Norvir, Norvir Soft Gelatin

• It is used to treat HIV infection.

• Generic Name: typhoid vaccine, live
• Dosage Forms: n.a.
• Other Brand Names: Vivotif Berna

Prevention of typhoid fever in US travelers planning to visit areas with a recognized risk of exposure to Salmonella enterica serovar Typhi.

Prevention of typhoid fever in individuals with intimate exposure (e.g., household contact) to a known typhoid carrier.

Prevention of typhoid fever in laboratory personnel with frequent contact with Salmonella Typhi bacilli.

Typhoid fever is a potentially severe and occasionally life-threatening, febrile, enteric illness caused by Salmonella Typhi. Usually acquired by ingestion of food and/or water contaminated with feces from individuals who have typhoid fever or are chronic typhoid carriers. Overall case-fatality rate in patients who receive early and appropriate antibacterial treatment is typically <1%; if left untreated, case-fatality rate may be ≥10–20%. Approximately 2–4% of individuals with acute typhoid fever develop a chronic carrier state.

Typhoid fever is uncommon in the US, but endemic in many less well-developed areas of the world that have poor sanitation and primitive water systems. About 22 million cases of typhoid fever and about 200,000 typhoid-related deaths occur annually worldwide. In the US, about 300–400 confirmed cases of typhoid fever are reported annually, almost all in recent travelers to other countries (most commonly southern Asia).

USPHS Advisory Committee on Immunization Practices (ACIP) and CDC state that routine vaccination against typhoid fever not recommended for individuals residing in the US, but preexposure vaccination is recommended for those at high risk of exposure to Salmonella Typhi.

When vaccination against typhoid fever indicated, either typhoid vaccine live oral Ty21a or typhoid Vi polysaccharide vaccine can be used unless contraindicated. Consider that the vaccines have different contraindications (see Contraindications under Cautions) and different minimum age limits for use in children (see Pediatric Use under Cautions). Other factors to consider when selecting a typhoid vaccine include immunization schedule, response time, patient compliance, storage facilities, and immunocompetence of the vaccinee (see Warnings/Precautions under Cautions). Because typhoid vaccine live oral Ty21a is self-administered over a 1-week period and compliance errors (i.e., dosing errors, improper storage) may occur, typhoid Vi polysaccharide vaccine may be preferred if compliance is likely to be a problem.

Efficacy of typhoid vaccine live oral Ty21a and typhoid Vi polysaccharide vaccine appear to be comparable when administered as recommended; neither vaccine is expected to provide protection against typhoid fever in all vaccine recipients.

Typhoid vaccines will not provide protection against S. enterica serovar Paratyphi or any Salmonella other than Salmonella Typhi and will not provide protection against other bacteria known to cause enteric disease.

Typhoid vaccines are not used for treatment of typhoid fever and should not be used in individuals with acute Salmonella Typhi infection or in chronic typhoid carriers.

There is no evidence to support use of typhoid vaccine to control common source outbreaks or disease following natural disasters or in individuals attending rural summer camps.

Preexposure Vaccination Against Typhoid Fever in High-risk Groups

Travelers to areas with a recognized risk of exposure to Salmonella Typhi should be vaccinated against typhoid fever. The disease is endemic in many less well-developed areas of the world that have poor sanitation and primitive water systems.

CDC recommends typhoid vaccination for travelers to many Asian, African, and Latin American countries, but no longer recommends typhoid vaccination for travelers to certain Eastern European and certain Asian countries. In recent years, most US cases of typhoid fever reported in individuals who had traveled to southern Asia (especially the Indian subcontinent including India, Bangladesh, or Pakistan) or Africa.

Although risk is greatest for travelers who have prolonged exposure to possibly contaminated food and beverages in areas with persistent typhoid epidemics or in smaller cities and villages or rural areas outside usual tourist itinerary, even short-term travel (<1 week) to high-incidence areas is associated with risk for typhoid fever.

In addition to vaccination, individuals traveling to areas with risk of typhoid fever should use caution in selecting food and water in these areas since the vaccines are not 100% effective and vaccine-induced immunity can be overwhelmed by a large inoculum of Salmonella Typhi. (See Limitations of Vaccine Effectiveness under Cautions.)

Vaccination against typhoid fever and other precautions (safe food and water precautions, frequent handwashing) are especially important for travelers to high-risk areas because fluoroquinolone-resistant and multidrug-resistant Salmonella Typhi have become common or are reported with increasing frequency in many regions of the world (e.g., Indian subcontinent, Africa).

The most recent information regarding geographic areas with a recognized risk of typhoid fever and additional information on vaccination and other precautions for prevention of typhoid fever are available from CDC.

Close contacts of chronic typhoid carriers with intimate exposure (e.g., household contact) to a documented Salmonella Typhi chronic carrier (defined as excretion of Salmonella Typhi in urine or stool for >1 year) should be vaccinated against typhoid fever.

Laboratory personnel routinely exposed to cultures of Salmonella Typhi or specimens containing the bacilli or who work in laboratory environments where these cultures or specimens are routinely handled should be vaccinated against typhoid fever.