Hepatitis A vaccine in the last-minute traveler
Section snippets
Early seroconversion rates after vaccination
Hepatitis A vaccines provide high immunogenicity. Antibodies to HAV (anti-HAV), including neutralizing antibody, rapidly develop within 2 weeks after 1 dose of vaccine. Protection due to vaccination relates to the presence of antibody; postvaccination protection has been associated with the onset of seroconversion and an anamnestic antibody response after a booster dose.8, 9, 10
The 2-week pretravel vaccination recommendation advocated by authorities is based on results of clinical trials that
“Protective” antibody levels reexamined
Natural immunity to HAV is a complex process; several distinct arms of the immune system are operative, including natural killer cells, human leukocyte antigen-restricted cytotoxic T cells, and B-cell antibody.16 On the basis of vast experience with immunoglobulin in protecting against HAV infection, antibody alone is known to provide high-level protection against clinical disease. However, the precise levels of antibody considered protective remain debatable.
Seroconversion is predicated on
Postexposure protection in outbreak studies and controlled trials
Although clinical disease with HAV has been seen as early as 15 days and as late as 50 days after exposure, the average incubation period for natural or experimental infection is 28 days.17, 18 An efficacy trial of a hepatitis A vaccine (Vaqta 25 U) was conducted in a high-risk closed religious community in upstate New York that had experienced annual outbreaks of hepatitis A.19 At the beginning of an outbreak, 519 children received the vaccine and 518 received placebo. Before day 21, 3 cases
Summary
On the basis of current knowledge of hepatitis A antibody kinetics in response to vaccine, the natural incubation period of HAV infection, and postexposure prophylaxis data from outbreak control and animal studies, the current recommendations on timing of hepatitis A vaccine administration clearly require reconsideration.
Theoretically, if an individual were immunized on the way to the airport, arrived at the destination, and were then exposed to HAV during the first meal of the ensuing trip,
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Health Information for International Travel, 2003–2004
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Value of hepatitis A immunization in the last minute traveler and the use of hepatitis A vaccine in outbreak control
Rapid protection and vaccination against hepatitis A for travellers
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Cited by (31)
Acute viral hepatitis a: A global health concern
2019, Emerging and Reemerging Viral Pathogens: Volume 1: Fundamental and Basic Virology Aspects of Human, Animal and Plant PathogensHepatitis B vaccination coverage among adults aged ≥ 18 years traveling to a country of high or intermediate endemicity, United States, 2015
2018, VaccineCitation Excerpt :The belief that short duration travel poses little risk for HBV infection also may be likely for travelers visiting friends and relatives in endemic areas. Travelers should seek consultation about vaccinations recommended for travel at least 4–6 weeks before travel, since many travel vaccines require multiple shots and take time to become fully effective [24–27]. Allowing sufficient time for pre‐travel hepatitis B vaccination is important.
Hepatitis A vaccination coverage among adults 18-49 years traveling to a country of high or intermediate endemicity, United States
2013, VaccineCitation Excerpt :Many travelers to nearby international destinations may fail to seek travel health advice [13] because of lack of awareness of the risk for travel associated infection [22] and travel related vaccination recommendations. Some travelers, such as business travelers, journalists and relief workers may be notified of travel on short notice and have little time for vaccination prior to departure even though these travelers should be vaccinated for planned travel to protect themselves and minimize business costs and liability [23]. Travelers’ may believe that travel of short duration, to resorts or on tours, will pose little risk of travel related diseases [22].
Hepatitis
2013, The Immunoassay Handbook: Theory and Applications of Ligand Binding, ELISA and Related TechniquesResponse to Hepatitis A Epidemic: Emergency Department Collaboration with Public Health Commission
2009, Journal of Emergency Medicine