Show Summary Details
Page of

Travel Vaccines 

Travel Vaccines
Chapter:
Travel Vaccines
Author(s):

Tina Q. Tan

, John P. Flaherty

, and Melvin V. Gerbie

DOI:
10.1093/med/9780190604776.003.0004
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 20 October 2019

Yellow Fever Vaccine

Did you know that:

  • The earliest recorded record of yellow fever comes from a Mayan manuscript discovered in the Yucatan from 1648.

  • Yellow fever was a major problem in the 18th century in colonial settlements in the Americas and West Africa. The disease was repeatedly introduced into seaports in the United States via sailing vessels infested with Aedes aegypti mosquitos that sustained transmission among the passengers and crew.

  • In 1793 an outbreak of yellow fever in Philadelphia, which at the time was the federal capital of the United States, killed 10% of the population.

  • The sweat of a person with yellow fever reportedly smells like a butcher’s shop.

Yellow fever (YF) is transmitted in forested areas of sub-Saharan Africa and South America but may spread to urban areas and in dry locations where stored water provides breeding sites. Figure 8 shows the areas of the world where YF is endemic. YF illness ranges in severity from a self-limited, febrile illness to hemorrhagic fever that is fatal in 50% of cases. Up to 50% of infections are asymptomatic. After an incubation period of 3 to 6 days, fever, headache, and myalgias begin abruptly, accompanied by conjunctival injection, facial flushing, relative bradycardia, and leukopenia. In most cases these symptoms resolve with no further complications. In severe cases, after a short period of resolution, the symptoms return with high fever, headache, back pain, nausea, vomiting, abdominal pain, and somnolence. This is followed by severe weakness, icteric hepatitis, and prominent gastrointestinal bleeding, hematemesis, epistaxis, gum bleeding, and petechial and purpuric hemorrhages. Ultimately hypotension, shock, and metabolic acidosis develop accompanied by myocardial dysfunction, arrhythmias, azotemia, confusion, seizures, and coma. Death may occur within 7 to 10 days. A traveler’s risk for acquiring yellow fever is determined by various factors, including immunization status, location of travel, season, duration of exposure, occupational and recreational activities while traveling, and local rate of virus transmission at the time of travel. From 1970 through 2013, a total of 10 cases of yellow fever were reported in unvaccinated travelers from the United States and Europe who traveled to West Africa (5 cases) or South America (5 cases). Eight (80%) of these 10 travelers died. The risk of acquiring yellow fever is difficult to predict because of variations in ecologic determinants of virus transmission. For a 2-week stay, the estimated risks for illness and death due to yellow fever for an unvaccinated traveler visiting an endemic area in:

  • West Africa are 50 per 100,000 and 10 per 100,000, respectively

  • South America are 5 per 100,000 and 1 per 100,000, respectively


Figure 8 Areas requiring yellow fever vaccination

Figure 8 Areas requiring yellow fever vaccination

Transmission

YF is transmitted by Aedes aegypti mosquitoes; the mosquitoes are infected after feeding on viremic humans and then spread the infection during subsequent feedings.

Incubation period

3 to 6 days after bite from infected mosquito

Treatment

No antiviral therapy is available. Treatment is supportive care.

Prevention

Preexposure prophylaxis

Yellow fever vaccine—live, attenuated 17D vaccine that is administered subcutaneously as single dose. Vaccine should be administered at least 10 days prior to travel. Compulsory vaccine is required by certain countries for entry and can only be administered by certified travel clinics. Vaccine may be administered with other live vaccines. If not given at the same time, other live vaccines should be given 3 weeks later.

Duration of immunity

Probably lifelong after 1 dose, however, a booster dose is recommended every 10 years if a person resides or frequently travels to an endemic area.

Contraindications and precautions to yellow fever vaccine

Contraindications

  1. 1. Immunocompromised host

  2. 2. Anaphylactic reaction to eggs/egg products or prior dose of vaccine and any of its components

  3. 3. Age younger than 6 months, except during epidemics.

Precautions

  1. 1. Infants between 6 and 9 months of age and persons ≥ 60 years of age due to a very small increased risk of post-vaccination encephalitis (1 person in 125,000).

  2. 2. Pregnancy—not recommended unless travel to a high-risk endemic area cannot be avoided or postponed. In areas where YF is endemic, or during outbreaks, the benefits of YF vaccination are likely to far outweigh the risk of potential transmission of vaccine virus to the fetus or infant. Pregnant women and nursing mothers should be counseled on the potential benefits and risks of vaccination so that they may make an informed decision about vaccination.

  3. 3. Breastfeeding—lactating women should be advised that the benefits of breastfeeding far outweigh alternatives. Vaccination is recommended, if indicated, for breastfeeding women traveling to endemic areas when such travel cannot be avoided or postponed or during epidemics.

Frequently asked questions

Does a patient need to avoid contact with immunocompromised family members after receiving the yellow fever vaccine?

No. There is no evidence that people who receive yellow fever vaccine shed the vaccine virus. Therefore, there is no need to avoid contact with persons who have weak immune systems.

How long should a woman wait to conceive after receiving a yellow fever vaccination?

Yellow fever vaccination has not been known to cause any birth defects when given to pregnant women and has been given to many pregnant women without any apparent adverse effects on the fetus. However, since yellow fever vaccine is a live virus vaccine, it poses a theoretical risk. While a two-week delay between yellow fever vaccination and conception is probably adequate, a 1-month delay has been advocated as a more conservative approach. If a woman is inadvertently or of necessity vaccinated during pregnancy, she is unlikely to have any problems from the vaccine and her baby is very likely to be born healthy.

Why is yellow fever vaccine not recommended to be given to adults 60 years and older even if they are traveling to an endemic area of the world?

People aged ≥60 years may be at increased risk for serious adverse events (serious disease or, very rarely, death) following vaccination, compared with younger persons. This is particularly true if they are receiving their first yellow fever vaccination. Travelers aged ≥60 years should discuss with their health-care provider the risks and benefits of the vaccine given their travel plans. In addition to considering the vaccine, travelers to endemic areas should protect themselves from yellow fever and other vector-borne diseases. Preventive measures include wearing clothes with long sleeves and long pants and using an effective insect repellent such as those with DEET, picaridin, IR3535, or oil of lemon eucalyptus.

Typhoid Fever Vaccine

Did you know that:

  • Mary Mallon (a.k.a. “Typhoid Mary”) immigrated from a small village in Northern Ireland in 1883 and served as a cook to wealthy families in New York City. She was responsible for at least 2 separate typhoid fever outbreaks resulting in infection of 51 persons and 3 deaths. Her poor hand hygiene caused her to spread disease so effectively.

  • Typhoid Mary spent a total of 26 years in forced isolation to prevent the spread of the disease. She died in 1938 while still in isolation.

  • Typhoid Mary was the first person in the United States identified as an asymptomatic carrier of the typhoid fever organism.

  • Wolfgang Amadeus Mozart suffered from smallpox and a bout of typhoid fever during his lifetime.

  • The sweat of a person with typhoid fever smells like freshly baked bread.

Typhoid fever is a global health problem with an estimated 26.9 million cases worldwide and 220,000 deaths each year. The disease is very common in developing countries, especially in the Indian subcontinent (India and Pakistan), Southeast Asia, South and Central America, and Africa. It is caused by several typhoidal Salmonella species, including S. typhi, S. enterica subtype enteritidis, and S. paratyphi. The onset of disease is gradual with symptoms ranging from mild to severe. The most common manifestations are high fever, headache, malaise, anorexia, lethargy, abdominal tenderness, hepatosplenomegaly, diarrhea or constipation, rose-colored spots on the trunk or abdomen, and changes in mental status. Persons with typhoid fever may excrete Salmonella organisms in their stools for months after having typhoid fever. This serves as a source of infection to their contacts. Complications may occur in up to 15% of patients. The most common complications include: GI bleeding, intestinal perforation, hepatitis, and encephalopathy. Five to 10% of patients will relapse even after receiving appropriate therapy.

Transmission

Acquisition of infection occurs by ingestion of fecally contaminated food or water (e.g., through handling by a person who is shedding S. typhi or if sewage contaminates the water used for drinking or washing food). Therefore, typhoid fever is more common in areas of the world where proper handwashing is less frequent and water is likely to be contaminated with sewage.

Incubation period

Incubation period is on average 8 to 14 days but ranges from 3 to 60 days or more.

Treatment

Response to antibiotic therapy is slow, and fever may persist for many days and even weeks after the patient’s blood culture has cleared. Third-generation cephalosporins, azithromycin, and fluoroquinolones are first-line antibiotics.

Prevention

Preexposure prophylaxis

Vaccine dosage and delivery are summarized in Table 18.

Table 18 Typhoid Fever Vaccines

Vaccine name

Type of vaccine

How given

Number of doses necessary

Time between doses

Time immunization should be completed by (before possible exposure)

Minimum age for vaccination

Booster needed every …

Ty21a (Vivotif Berna, Swiss Serum and Vaccine Institute)

Live, attenuated, oral

PO—by mouth

4

2 days

1 week

6 years

5 years

ViCPS (Typhim Vi, Pasteur Merieux)

Inactivated

IM—Injection

1

N/A

2 weeks

2 years

2 years

Contraindications and precautions for typhoid fever vaccine

Contraindications

  1. 1. Persons with history of anaphylaxis after previous administration of the vaccine and in persons with suspected or proven hypersensitivity to any component of the vaccine.

  2. 2. For oral live, attenuated vaccine:

    1. i. Pregnancy

    2. ii. Individuals with an acute gastrointestinal condition or inflammatory bowel disease

    3. iii. Persons with known or suspected immunocompromising condition

Precautions

  1. 1. Persons with severe acute illness with or without fever

  2. 2. For oral live, attenuated vaccine:

    1. i. Persons who are taking antibiotics or certain antimalarials that may kill the organism in the vaccine.

Frequently asked questions

How long can an infected person carry the typhoid fever bacteria?

The duration of the carrier stage varies from days to years. Only about 3% of patients go on to become lifelong carriers and this tends to occur more often in adults than in children.

One of my relatives returned from a trip to Pakistan and has typhoid fever. Should my relative be kept away from other family members when they return home?

Only people with active diarrhea who are unable to control their bowels (e.g., infants, certain disabled individuals, persons with copious diarrhea) should be isolated. Most infected people may return to work or school when they have been appropriately treated with antibiotics, provided they carefully wash their hands after using the toilet. Children in daycare should obtain approval from the Department of Public Health before returning to their routine activities. Food handlers and those who provide patient care may not return to work until three consecutive negative stool specimens are obtained.

Japanese Encephalitis Vaccine

Did you know that:

  • Mosquito larvae infected with the Japanese encephalitis virus are found in flooded rice fields, marshes, and small stable collections of water around cultivated fields. Pigs and certain species of wild birds actually amplify the virus in their bloodstreams when bitten, so areas where these animals are prevalent are areas of highest risk. Habitats supporting the transmission cycle of JE virus are principally in rural, pig farming, and rice paddy locations. Traveling and living “off the grid” in these locations places one at high risk for contracting this disease.

  • Seizures with the disease occur in over 75% of pediatric patients but much less frequently in adults.

Japanese encephalitis (JE) virus is a Flavivirus that is an arthropod borne infection. It is transmitted in Asia over an area spanning one third of the world’s circumference, from Pakistan at the westernmost edge to far eastern Russia. The disease is endemic and epidemic in Southeast Asia, China, and the Asian subcontinent, including Indonesian and the Philippines (see Figure 9 for endemic areas). Most infections with JE virus are asymptomatic. In countries where disease is endemic, infections acquired naturally at an early age results in immunity in over 80% of young adults. Symptomatic infections occur primarily in children between 2 and 10 years of age with higher incidence in males. Travelers of all ages without naturally acquired protective antibodies are at risk for acquisition of the illness. Infection is symptomatic in less than 1% of cases of JE, but the illness usually presents as a severe encephalitis, leading frequently to coma and to a fatal outcome in 25% of cases.


Figure 9 Map showing endemic areas for Japanese encephalitis

Figure 9 Map showing endemic areas for Japanese encephalitis

The earliest symptoms are lethargy, fever, headache, abdominal pain, nausea, and vomiting. Lethargy increases over several days associated with agitated delirium, unsteadiness, and abnormal motor movements, advancing to progressive somnolence and coma. Multiple seizures and status epilepticus are associated with a poor outcome. Neurologic abnormalities persist in up to one-third of patients. A large proportion of recovered children (up to 75%), exhibit behavioral and psychological abnormalities. Illness acquired in the first and second trimesters of pregnancy may precipitate abortion.

Incubation

Incubation period is 5 to 15 days after being bitten by an infected mosquito.

Transmission

The virus is transmitted by the Culex tritaeniorhynchus and related ground-pool-breeding mosquitoes to pigs and aquatic birds, which are the principal viral amplifying hosts. Viremic adult pigs are asymptomatic, but infected pregnant sows abort or deliver stillbirths. Infected horses and humans are symptomatic. Rice paddies provide favorable breeding habitats for vector mosquitoes: therefore, the risk of infection is highest in rural areas with rice growing, pig farming, and horses, especially if the traveler is staying this area for more than 3 weeks.

Travelers at the highest risk are those who will be staying in rural rice-growing and pig-farming endemic areas for at least 3 weeks, engaging in extensive outdoor activities (e.g., camping, hiking, fishing, biking) in rural areas, and staying in accommodations that lack window screens, air conditioning, or bed nets.

Treatment

There is no specific therapy for JE encephalitis outside of supportive care.

Prevention

Preexposure prophylaxis

Japanese encephalitis vaccine: Ixaro is an inactivated vaccine that is a 2-dose series with doses given 28 days apart. Doses should be completed at least 1 week prior to travel. It is licensed for use in persons ≥2 months of age. It is administered as:

  • A 0.5 ml IM dose to persons ≥3 years of age

  • A 0.25 ml IM dose to persons 2 months through 2 years of age.

Booster dose

Recommended for persons ≥17 years of age if continued exposure anticipated and greater than 1 year has elapsed since completion of the primary 2-dose series.

Contraindications and precautions for Japanese encephalitis vaccine

Contraindications

  • Severe allergic reaction (e.g., anaphylaxis) to a previous dose of vaccine or any vaccine component.

Precautions

  1. 1. Moderate or severe acute illness with or without fever.

  2. 2. Pregnancy—theoretical risk to the fetus, however, no deleterious effects have been demonstrated from JE vaccine administration during pregnancy, and the risk of adverse fetal effects from an inactivated vaccine is extremely low.

Duration of protection

Unknown

Frequently asked questions

Can a person get infected through close contact with an infected person?

No. JE virus has not been shown to be transmitted from person to person.

Can a person contract JE through eating pork that comes from an endemic area?

No. Once the pig is slaughtered the JE virus will not survive in the pork meat. JE virus can only survive in living cells. Any virus will be killed by cooking, roasting, or boiling the meat at a temperature of more than 60 degrees Celsius and the digestive enzymes and acid in our stomach will also kill the virus.

Rabies Vaccine

Did you know that:

  • The earliest reported description of rabies is before 2300 bc in the Mesopotamian Laws of Eshnunna.

  • Quote from Lewis Thomas in The Lives of a Cell, 1974: “I have seen agony in death only once, in a patient with rabies: he remained acutely aware of every stage in the process of his own disintegration over a twenty four-hour period, right up to his final moment.”

Rabies is an acute illness with rapidly progressive central nervous system manifestations including anxiety, radicular pain, dysesthesia or pruritus, hydrophobia, and dysautonomia or paralysis. Illness almost invariably progresses to death. The disease has 3 sequential stages: (1) The prodromal stage, which lasts for 2 to 10 days and is characterized by fever, headache, malaise, fatigue, anorexia, anxiety, agitation, irritability, insomnia, depression, and pain, pruritus, or paresthesia at the site of the bite; (2) the acute neurologic state, which lasts 2 to 12 days, is characterized by hyperactivity, disorientation, hallucinations, bizarre behavior, aggressiveness, seizures, paralysis, aerophobia, hyperventilation, and cholinergic manifestations, including hypersalivation, lacrimation, mydriasis, and hyperpyrexia, with paralysis occuring in 20% of cases; (3) at the end of the neurologic stage, the patient may become comatose. Death from cardiorespiratory arrest usually occurs within 7 days, although with supportive care, coma may last for months. Each year, there are an estimated 70,000 human rabies cases worldwide, with only 1 to 2 cases occurring in the United States. Disease is almost always fatal.

Transmission

The virus is present in the saliva of a number of different animals and is transmitted by bites or by contamination of mucosa or skin lesions by saliva or other potentially infectious material. In the United States, bats, raccoons, skunks, foxes, wolves, coyotes, and bobcats, are the most important sources of infection for humans and domestic animals. Worldwide, most human cases of rabies result from dog or cat bites. Transmission also has occurred by transplantation of organs, corneas, and other tissues from patients dying of undiagnosed rabies.

Incubation period

The incubation period is 1 to 3 months but ranges from days to years.

Treatment

There is no specific treatment.

Prevention

Post-exposure

  1. a. Post-exposure prophylaxis is recommended for all persons bitten by wild mammalian carnivores or bats or by domestic animals that are suspected to be rabid. It is also recommended for people who report an open wound, scratch, or mucous membrane that has been contaminated with saliva or other potentially infectious material from a rabid animal.

  2. b. The injury inflicted by a bat bite or scratch may be small and not readily evident, or the circumstances of contact with a bat may preclude accurate recall (e.g., a bat in a room of a deeply sleeping or medicated person, or an unattended child, especially an infant or toddler who cannot reliably communicate about a potential bite). Therefore, postexposure prophylaxis may be indicated, for situations in which a bat physically is present in the same room if a bite or mucous membrane exposure cannot reliably be excluded, unless prompt testing of the bat has excluded rabies virus infection. Prophylaxis should be initiated as soon as possible after bites by known or suspected rabid animals.

  3. c. The immediate objective of postexposure prophylaxis is to prevent virus from entering neural tissue. Prompt and thorough local treatment of all lesions is essential because virus may remain localized to the area of the bite for a variable time. All wounds should be flushed thoroughly and cleaned with soap and water. After wound care is completed, concurrent use of passive and active prophylaxis is optimal. The exception is in persons who previously have received complete vaccination regimens with a cell culture vaccine or people who have been vaccinated with other types of rabies vaccines and have previously had a documented rabies virus-neutralizing antibody titer; these people should receive only vaccine.

  4. d. Prophylaxis should begin as soon as possible after exposure, ideally within 24 hours. However, a delay of several days or more may not compromise effectiveness, and prophylaxis should be initiated if reasonably indicated, regardless of the interval between exposure and initiation of therapy.

Passive prophylaxis—rabies immune globulin (RIG)—in the United States, only human RIG is available. The dosing is 20 IU/kg—wound site should be infiltrated with as much of the RIG as possible and any remaining volume should be administered intramuscularly. This should be used concomitantly with the first dose of vaccine to bridge the time between possible infection and antibody production induced by the vaccine.

Active prophylaxis—Human diploid cell vaccine (Imovax) and purified chicken embryo cell vaccine (RabAvert) are available for use in the United States.

  1. a. For a previously unvaccinated immunocompetent person, a 1.0 ml dose of vaccine is given IM in the deltoid area (the anterolateral aspect of the thigh is also acceptable for children) on the first day of postexposure prophylaxis (Day 0), and repeated doses are given on days 3, 7, and 14 after the first dose for a total of 4 doses, with one dose of RIG given on day 0.

  2. b. For a person with altered immunocompetence, postexposure prophylaxis should include a 5-dose vaccination regimen (i.e., 1 dose of vaccine on days 0, 3, 7, 14, and 28), with 1 dose of RIG on day 0.

Preexposure

  1. a. Preexposure prophylaxis is recommended for people in high-risk groups, including veterinarians, animal handlers, certain laboratory workers, and people moving or traveling to areas where canine rabies is common. Others, such as spelunkers (cavers) or animal rehabilitators, who may have frequent exposures to bats and other wildlife, should also be considered for preexposure prophylaxis.

  2. b. The preexposure prophylaxis vaccine schedule is a 3-dose series given as a 1.0 mL IM injection on days 0, 7, and 21 or 28.

Duration of protection

Serum antibodies usually persist for 2 years or longer after the primary series is administered IM.

Contraindications and precautions for rabies vaccine

Contraindications

In the situation of exposure to rabies, there are no contraindications to vaccination or use of HRIG.

Precautions

  1. 1. Severe allergic reaction (e.g., anaphylaxis) to a previous dose of vaccine or any vaccine component.

  2. 2. Immunosuppression—immunosuppressive agents should not be administered during postexposure prophylaxis unless absolutely essential. If possible, preexposure prophylaxis should be postponed until immunocompromising conditions are resolved. When an immunosuppressed person is given pre- or postexposure prophylaxis, antibody titers should be checked.

  3. 3. Patients with selective IgA deficiency may be at increased risk for anaphylactic reactions to HRIG because it may contain trace amounts of IgA.

Frequently asked questions

My granddaughter just received two hamsters for her birthday. Can these small rodents transmit rabies to humans?

Rabies in small rodents (e.g., squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, and mice) and lagomorphs such as rabbits, pikas, and hares is very rare and do not pose a rabies infection risk.

Is it possible to develop rabies from the rabies vaccine?

No, all rabies vaccines used in humans are inactivated and therefore it is not possible for the vaccine to cause disease.

Cholera Vaccine

Did you know that:

  • Reports of cholera-like disease have been found as early as 1000 ad.

  • Cholera has the distinction of being among the most rapidly fatal infectious diseases of humans with the ability to cause death within 6 to 12 hours of onset of clinical symptoms.

  • Prior to the development of effective rehydration therapy with intravenous and oral fluids, cholera epidemics were associated with case-fatality rates that exceeded 60% and led to tens of thousands of deaths.

  • The diarrhea of cholera is described as “rice-water stool.” The stools are watery and often contain flecks of whitish material (mucus and some gastrointestinal lining cells) that are about the size of pieces of rice and smells “fishy.”

  • The volume of diarrhea can be enormous with as much as 250 cc per kg or about 10 to 18 liters of diarrhea fluid lost over a 24-hour period.

Cholera is an acute, rapidly dehydrating, watery, painless diarrheal disease caused by infection with toxogenic strains of the bacterium Vibrio cholerae serogroups O1 and O139. Serogroup O1 is the most common. The World Health Organization estimates that about 3 to 5 million people are infected worldwide each year, with approximately 100,000 deaths per year. Figure 10 shows the areas of the world where cholera outbreaks continue to be a problem. Cholera is now endemic in over 50 countries and can appear in explosive epidemics. Since the early 1800s, there have been 7 cholera pandemics. The current pandemic began in 1961 and is caused by V. cholerae O1 El Tor.


Figure 10 Cholera, areas reporting outbreaks 2010–2014

Figure 10 Cholera, areas reporting outbreaks 2010–2014

Cholera manifests as an acute, severe watery, painless diarrhea that can lead to death from dehydration within hours of onset. The spectrum of disease ranges from asymptomatic intestinal colonization (observed in individuals with preexisting immunity) to mild, moderate, and severe diarrhea. In severe diarrhea, the volume of watery stool can exceed 1L/hour. Vomiting is common, however, and patients are usually afebrile. As the dehydration worsens, patients may also experience muscle pain and spasm. In addition to potentially life-threatening dehydration and hypovolemia, common complications of cholera include hypokalemia, metabolic acidosis, and hypoglycemia.

Transmission

Transmission occurs through the consumption of contaminated water or food (especially raw or undercooked shellfish, raw or partially dried fish, or moist grains or vegetables stored at ambient temperature) and is often the result of a combined contamination. For example, contaminated water is often used to wash fresh food therefore contaminating the food. Spread of the infection is by the fecal-oral route and is associated with inadequate sanitation and unsafe water.

Incubation period

The incubation period is 1 to 3 days with a range of a few hours to 5 days.

Treatment

  1. a. The cornerstone of management is appropriate rehydration therapy. Rehydration therapy should be based on WHO standards, with the goal of replacing the estimated fluid deficit within 3 to 4 hours of initial presentation. In patients with severe dehydration, isotonic intravenous fluids should be used, and lactated Ringer solution is the preferred commercially available option. For patients without severe dehydration, oral rehydration solution is the standard.

  2. b. Prompt initiation of antimicrobial therapy decreases the duration and volume of diarrhea and decreases the shedding of viable bacteria. Antimicrobial therapy is recommended only for people who are moderately to severely ill. Table 19 shows the antibiotics for treatment of suspected cholera.

Table 19 Antibiotics for Treatment of Suspected Cholera

Antibiotic

Pediatric Dose

Adult Dose

Azithromycin

20 mg/kg, single dose

1 gram, single dose

Ciprofloxacin*

15 mg/kg, twice daily X 3 days

500 mg, twice daily X 3 days

Doxycycline**

4–6 mg/kg, single dose

300 mg, single dose

Erythromycin

12.5 mg/kg, 4 times/day X 3 days

250 mg, 4 times/day X 3 days

Tetracycline

12.5 mg/kg, 4 times/day X 3 days

500 mg, 4 times/day X 3 days

*Ciprofloxacin is not recommended in children or pregnant women

** Doxycycline is not recommended in children younger than 8 years or in pregnant women

Prevention

  1. a. A cholera vaccine (Vaxchora) was recently approved by the FDA for use in the United States. Preexposure prophylaxis is recommended for persons 18 to 64 years of age traveling to cholera-affected countries.

  2. b. The vaccine is a live, attenuated vaccine that is taken as a single, oral liquid dose (~3 fl oz) at least 10 days prior to traveling to a cholera-affected area to protect against disease caused by V. cholerae serogroup O1.

  3. c. Most common reported adverse reactions were tiredness, headache, abdominal pain, nausea/vomiting, lack of appetite, and diarrhea.

Duration of protection and efficacy

Unknown. Based on data from randomized, placebo controlled human challenge studies (challenged by oral ingestion of V. cholerae) the vaccine demonstrated an efficacy of 90.3% among persons challenged 10 days post-vaccination and 80% among those challenged 3 months post-vaccination.

Contraindications and precautions for cholera vaccine

Contraindications

Persons with a history of severe allergic reaction (e.g., anaphylaxis) to any ingredient of this cholera vaccine or to a previous dose of any cholera vaccine.

Precautions

  1. 1. The safety and effectiveness has not been established in immunocompromised persons or persons receiving immunosuppressive therapies. Vaccine strain may be shed in the stool of recipients for at least 7 days. There is a potential for transmission of the vaccine strain to non-vaccinated close contacts.

  2. 2. The safety and effectiveness has not been established in children and adolescents younger than 18 years or in adults over 65 years.

Frequently asked questions

Where do cholera outbreaks occur?

Cholera outbreaks occur in areas where there are natural disasters or in situations where there is a loss of sanitary human waste disposal and lack of clean water and foods for people to eat. In developing countries, hunger can lead people to eat contaminated food and/or drink contaminated water which increases the risk for cholera to infect malnourished populations.

Are there persons that are at higher risk to become infected with cholera than others?

Yes. People who are malnourished or immune compromised and children aged 2 to 4 years are more likely to become infected. Also people with blood type O are twice as likely to develop cholera and people with achlorhydria (reduced acid secretion in the stomach) or persons taking medications to reduce stomach acid (e.g., H2 blockers) are more likely to develop cholera because stomach acid kills the cholera organism.

How contagious is cholera?

It takes about 100 million V. cholerae bacteria to infect a healthy adult. Because this number is so high, significant contamination of food or water is required to transmit the disease. In outbreaks, cholera causing bacteria become highly contagious indirectly and directly by the fecal-oral route because of widespread fecal contamination of food, water, and items like bedding and clothing.