By Philip R. Fischer, MD, DTM&H
Professor of Pediatrics, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN; Department of Pediatrics, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
SYNOPSIS: Hepatitis A continues to be a problem for international travelers in much of the world. More widespread use of hepatitis A vaccine could be warranted.
SOURCE: Balogun O, Brown A, Angelo KM, et al. Acute hepatitis A in international travellers: A GeoSentinel analysis, 2008-2020. J Travel Med 2022;29:taac013.
Of the more than 1 million cases of hepatitis A each year, most occur in Africa, Asia, Eastern Europe, Central America, and South America. With improved water supply and sanitation, along with vaccination, infection rates have decreased in some countries. However, international travelers still are at risk of becoming ill with hepatitis A.
Generally, hepatitis A vaccination is recommended prior to international travel, but many travelers do not avail themselves of vaccination.
GeoSentinel is a global clinician-based surveillance system managed collaboratively by the Centers for Disease Control and Prevention (CDC) and the International Society of Travel Medicine. It involves 68 sites in 28 countries and gathers data on infections and other adverse health events in international travelers.
The GeoSentinel Surveillance Network database was used to evaluate travel and traveler details in patients seen with hepatitis A at GeoSentinel sites from 2008 through 2020. A total of 254 cases were included in this analysis.
Among affected travelers, the ages ranged from 1 to 75 years (median, 28 years; 47% aged 20-39 years); 41% were female. Among those who became ill with hepatitis A, 47% had been traveling as tourists, 28% had been visiting friends and relatives, and 14% had been traveling for business. The mean duration of symptoms was seven days by the time of presentation to a GeoSentinel site, and 59% of ill travelers for whom disposition data were available were hospitalized. Most travelers became ill with hepatitis A after travel to areas of known endemicity (25% South Central Asia, 24% sub-Saharan Africa, and 17% North Africa). However, 11 travelers to low-endemicity areas also developed hepatitis A (three in the United States, three in Thailand, and two in Spain).
Overall, 78% of those who developed travel-related hepatitis A had not had a pre-travel consultation. Vaccination history was known only for 54 of the affected travelers; 53 had not been vaccinated, and the other one had received a single vaccine dose more than a year prior to the trip.
The authors rightly identified two groups of people accounting for many of the patients. First, young adults (20-39 years of age) accounted for nearly half of the patients. This group might have been born prior to routine childhood hepatitis A immunization in their home countries. Second, more than one-fourth of those identified with hepatitis A were traveling to visit friends and relatives; it is this group that often opts not to seek pre-travel care, perhaps thinking they are safe since they are just going home.
COMMENTARY
Current (2020) CDC recommendations are that hepatitis A vaccine be given to children, to “adults at risk” (including people who are homeless and men having sex with men, as well as individuals with human immunodeficiency virus or chronic liver disease), and to international travelers.1 There are two licensed hepatitis A single-agent vaccines in the United States, and there also is a combined hepatitis A and hepatitis B vaccine licensed in the United States.1 Each vaccine gives > 95% protection, and immunity after the two-dose series appears to be for at least 30 years.1
The GeoSentinel study used a convenience sample of travelers who sought illness care at a GeoSentinel site. Thus, this study cannot be construed as showing a population-based risk. Nonetheless, these new data fully support the CDC recommendation that international travelers should have hepatitis A vaccination. And the fact that hepatitis A occurred in travelers from other countries visiting the United States serves as a good reminder that there is risk of infection even in short-term visitors to the United States.
The CDC hepatitis A vaccination guidelines also suggest vaccination “for adults requesting protection against hepatitis A virus without acknowledgment of a risk factor.”1 Clearly, hepatitis A vaccination is efficacious for all children, and adults are at higher risk of severe symptoms with infection than are young children. One wonders if we should soon agree that hepatitis A vaccination be recommended for all adults.
In recent months, clusters of childhood hepatitis cases have been identified in children in Alabama, Scotland, and elsewhere.2-4 Adenovirus type 41 has been identified in some cases.2
REFERENCES
- Nelson NP, Weng MK, Hofmeister MG, et al. Prevention of hepatitis A virus infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020. MMWR Recomm Rep 2020;69:1-38.
- Baker JM, Buchfellner M, Britt W, et al. Acute hepatitis and adenovirus infection among children – Alabama, October 2021-February 2022. MMWR Morb Mortal Wkly Rep 2022;71:638-640.
- Marsh K, Tayler R, Pollock L, et al. Investigation into cases of hepatitis of unknown aetiology among young children, Scotland, 1 January 2022 to 12 April 2022. Euro Surveill 2022;27:2200318.
- World Health Organization. Multi-country – acute, severe hepatitis of unknown origin in children. Published April 23, 2022. https://www.who.int/emergencies/disease-outbreak-news/item/multi-country-acute-severe-hepatitis-of-unknown-origin-in-children
Hepatitis A continues to be a problem for international travelers in much of the world. More widespread use of hepatitis A vaccine could be warranted.
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