Now that COVID-19 pandemic travel restrictions are beginning to ease, our patients are boarding flights and boats in record numbers. Be sure to discuss upcoming travel plans with your patients and discuss the need for routine immunizations (including COVID-19) and any potential travel-related vaccinations at least one month prior to their departure.
Advising patients prior to travel requires you to understand current outbreaks in the travel area along with endemic diseases that are preventable through prophylaxis. A handy website to bookmark and to provide to your patient is the Centers for Disease Control and Prevention (CDC) website on travel health. (https://wwwnc.cdc.gov/travel). This website is a wealth of information to you as a physician but may be overwhelming to your patient.
Take some time to discuss travel health notices and updates with your patient, particularly if the patient is immunocompromised or pregnant. Discuss the use of prophylactic vaccinations or medications along with preventative strategies, such as the utilization of DEET-based insect repellant, mosquito netting, hand washing, choosing food and drink carefully and safe sex practices to minimize travel-related illnesses.
Here are some common travel-related illnesses and the prophylactic methods against them.
Travel Illnesses Spread by Ingestion of Contaminated Food or Water
Traveler’s diarrhea
Traveler’s diarrhea is the most common travel-related illness, and it’s important enough to discuss here despite the lack of vaccine prevention. The majority of traveler’s diarrhea is bacterial in etiology. Prophylaxis for patients who have underlying severe inflammatory bowel disease; severe vascular, cardiac or renal disease; or who have known severe immunosuppression from transplant or advanced HIV may be appropriate.
There are two drugs currently recommended for prophylaxis of traveler’s diarrhea: rifaximin (first line), and bismuth subsalicylate (second line). For those patients who do not meet the criteria for prophylaxis, discuss traveler’s diarrhea severity and management with your patient, and send your patient with an antibiotic and some loperamide along with instructions.
Hepatitis A
Hepatitis A (HAV) is a common virus transmitted mainly through the fecal-oral route. Hepatitis A is fully preventable and is now a routine pediatric immunization in the United States.
HAV symptoms include abrupt onset abdominal pain, nausea, vomiting, diarrhea and jaundice. It is typically disabling but self-limiting. Patients with underlying liver disease, pregnant patients and immunocompromised patients are at risk for severe sequelae from HAV.
Vaccines are safe in immunocompromised and pregnant individuals and typically require two (monovalent choices) to three (combined HAV/HBV) doses to complete the vaccination series.
Advise your unvaccinated patients to get at least one dose of vaccine as quickly as possible. A single dose provides protection to most travelers, especially when the vaccine is administered one month prior to departure.
Typhoid
Salmonella enterica S. Typhi, the causative agent for typhoid fever, has burdened developing countries for centuries. It is typically transmitted via the fecal-oral route and commonly ingested in contaminated food and water. The bacteria is commonly found in countries with poor sanitation infrastructure. Symptoms include high fever, weakness, stomach pain, diarrhea and occasional rash.
Two types of vaccinations are available: oral live-attenuated and intramuscular polysaccharide vaccine. The live-attenuated oral (pill) vaccine is appropriate for patients who are older than 6 and can swallow pills. It needs to be completed one week prior to travel. As this vaccine is live attenuated, certain immunocompromised populations should avoid it. It can protect your patient for up to 5 years. The polysaccharide vaccine protects your patient for 2 years and should be administered two weeks prior to travel (either initial shot or booster if >2 years have lapsed since last dose).
Neither typhoid vaccine offers 100% protection, so you should emphasize careful food and drink choices for your patients. Patients going to visit friends and relatives are at higher risk of acquiring typhoid fever because of less careful food and drink choices.
Cholera
Vibrio cholerae is the pathogen associated with cholera, a once feared but now rare form of deadly diarrhea. Transmitted via the fecal-oral route, outbreaks of cholera are typically associated with food or water contamination.
Cholera risk is highest in areas of the world with poor sanitation infrastructure. Travelers to a cholera endemic area or an area with recent (1 year or less) cholera outbreak should consider vaccination with Vaxchora, particularly travelers to remote areas where rapid receipt of treatment for cholera is unlikely. Vaxchora is a live attenuated vaccine given at least 10 days prior to travel for individuals aged 2-64.
Travel Illness Spread by Direct Contact
Hepatitis B
Hepatitis B virus (HBV) is a global illness spread through blood and body fluids of infected people. HBV can cause acute hepatitis similar to HAV infection; however, unlike HAV, HBV can develop into a chronic infection.
Many different formulations of highly effective vaccination exist, and HBV vaccination became part of routine childhood immunization series in the United States in 1991. Current available vaccination formulations include: Heplisav-B as a two-dose (day 0 and 1 month) or Engerix-B, Recombivax HB and Twinrix (HAV/HBV) as a three-dose, 0-, 1-and 6 month schedule.
Unvaccinated travelers of all ages traveling to areas of endemic HBV transmission should receive vaccination prior to departure. HAV/HBV unvaccinated travelers can receive Twinrix (HAV/HBV) in the following accelerated schedule: day 0, 7 and 21-30 with a booster at 12 months for long-term immunity.
Bacterial meningitis
Neisseria meningitidis causes outbreaks of bacterial meningitis (meningococcal disease). Without prompt and proper medical therapy, meningococcal disease cases can be rapidly fatal. Close contact with respiratory secretions spreads disease.
Vaccination against serotypes A, C, W and Y (MenACWY) is part of routine childhood immunizations in the United States for older, school-aged children. Individuals traveling to Saudi Arabia for the Hajj or Umrah pilgrimages must show proof of MenACWY vaccination. Additionally, travelers to sub-Saharan Africa should receive MenACWY as well. Sub-Saharan Africa is dubbed “the meningitis belt,†and it has the highest rate of meningococcal disease in the world, with transmission peaks during the dry season (December-June).
Tell your unvaccinated patients to receive their vaccine 10 days or more prior to departure. Additionally, those traveling to hyperendemic areas should receive MenACWY boosters every 5 years. Meningitis B vaccination is not recommended for travel unless an outbreak of serogroup B disease has been reported.
Rabies
Rabies is an encephalomyelitis caused by members of the Rhabdoviridae family. A zoonotic disease, rabies is a rare but nearly always fatal infection with no known treatment. Rabid dog bites are typically responsible for the majority of cases in travelers. For travelers going cave exploring or working with animals or for certain long-term travelers, rabies vaccination should be considered as pre-exposure prophylaxis.
Pre-exposure prophylaxis is a series of three vaccines given at day 0, 7, and 21 or 28. If the three-vaccine series cannot be completed prior to travel, it should not be started. Travelers vaccinated against rabies still need to receive post-exposure prophylaxis if a bite does occur.
Travel Illnesses Transmitted by Vectors
Japanese encephalitis
This flavivirus is spread through mosquito (mostly Culex spp) bites. It is the most common vaccine-preventable cause of encephalitis in Asia. Travel risks include those visiting rural areas and travelers staying for more than 1 month. While the majority of disease is asymptomatic, travelers who develop acute encephalitis, commonly with flaccid paralysis or choreoathetoid movements, are at risk for death and serious neurologic sequelae. Two doses of the vaccine should be completed one week prior to travel.
Yellow Fever
Another mosquito-borne flavivirus, this virus is common in tropical regions with some areas having seasonal endemicity. The majority of patients have mild courses of illness with nondescript symptoms; however, some people may develop fevers, chills, nausea and vomiting as prodromal symptoms with acute jaundice and hemorrhagic symptoms after a brief remission. Case fatality rate for severe disease is high, quoted as 30-60% in CDC yellow book.
A yellow fever vaccine is available, and it is a live attenuated virus. Yellow fever vaccination is only recommended to those travelers at high risk of exposure to disease or for areas that require proof of vaccination, as this vaccine has reports of associated serious adverse neurologic and viscerotropic diseases.
Malaria (Plasmodium spp)
A common mosquito (Anopheles) borne illness, the protozoan parasitic genus Plasmodium is responsible for this disease. While malaria is not vaccine-preventable, there are a multitude of oral regimens available for prevention. Drug regimens vary based on region of travel because of different distribution of Plasmodium species across the globe. Since malaria can be fatal, even with treatment, prophylaxis is preferred.
All regimens require an initial loading phase prior to departure for the destination. Some of the more common regimens include atovaquone-proguanil, mefloquine and doxycycline. Depending on where your patient is traveling, there may be a recommended terminal prophylaxis time period to prevent relapse or delayed onset disease caused by certain species (P. vivax and P. ovale). Many malaria prophylaxis regimens are contraindicated in patients with G6PD deficiency.
Many of the preventable, travel-related illnesses require vaccination through travel clinics since the majority of vaccines are not part of the routine vaccines recommended in the United States. However, routine immunizations are just as important for individuals traveling as vaccinations specific to their destinations. Take some time to discuss upcoming travel with your patients, review their immunizations and come up with a plan to minimize illness during their travels.
References:
- Centers for Disease Control and Prevention Travelers Health: https://wwwnc.cdc.gov/travel. Last accessed 7/23/2021.
- N’cho HS, Wong KK, Mintz, ED. “Choleraâ€. Center for Disease Control and Prevention Yellow Book. Chapter 4, online access wwwnc.cdc.gov
- Nelson, NP. “Hepatitis Aâ€. Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Harris, AM. “Hepatitis B†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Hills, SL, Lindsey NP, Fischer M. “Japanese Encephalitis†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Mbaeyi, SA, McNamara LA. “Meningococcal Disease†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Tan KR, Arguin PM. “Malaria†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Wallace RM, Petersen BW, Shilm DR. “Rabies†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
- Gersham MD, Staples JE. “Yellow Fever†Centers for Disease Control and Prevention Yellow Book. Chapter 4. Online access wwwnc.cdc.gov
Dr. Bronwen Garner
Dr. Garner practices infectious disease at Piedmont Atlanta Hospital and oversees medical microbiology for Piedmont Healthcare. She trained at Duke University for residency and infectious disease fellowship and The University of Utah for her microbiology fellowship.Â
