Hepatitis A vaccination: A reminder about last-minute and post-exposure use

Author(s):  Dr Sherilyn Houle

In August 2025, the U.S. Embassy in Cuba reported an increase in cases of hepatitis A in Havana.¹ In January 2026 it was reported that several suspected cases of hepatitis A in the province of Ciego de Ávila were under monitoring.² The Canadian government has updated their travel advice and advisories to Cuba to reflect reported cases of hepatitis A in returning travelers from Cuba.³

While the current context in Cuba is important for travelers there and those who provide pre-travel care to them, hepatitis A is a worldwide risk. While exposure risk may be higher for travelers visiting developing countries, rural or remote areas, trekkers, or those eating or drinking in areas with poor sanitation, food exposures even in regions with low levels of endemic transmission occur.⁴

Vaccination is recommended for most travelers to developing countries and areas with high or intermediate hepatitis A endemicity.^4-5 While monovalent vaccines follow a 2-dose series, it is important for health professionals and travelers to know that even a single dose can protect most travelers, since the vaccine is highly immunogenic (91%-99.7% seroconversion 1 month after a single dose) and protective antibody levels have been found to persist for at least 10 years after a single dose—sufficient to cover the duration of most travels.⁶ The long average incubation period for the hepatitis A virus of 28 days (range 15-50) provides additional reassurance that a last-minute dose can be protective, alongside evidence that vaccination can be effective as post-exposure prophylaxis if given within 2 weeks of exposure.⁷

The bottom line is to vaccinate, including last-minute travelers or those who are unvaccinated and have recently returned from a region where they may have been exposed. As the full duration of protection from a single dose remains undetermined, a second dose (for monovalent vaccines) remains recommended at least 6 months after the initial dose for long-term protection.⁶

References

[1].  Health Alert: hepatitis A.  ‐ U.S. Embassy in Cuba [link]
[2].  Health authorities are investigating a possible hepatitis outbreak in Ciego de Ávila.  Hernandez DB ‐ Invasor [link]
[3].  Cuba travel advice.  Government of Canada [link]
[4].  Hepatitis A.  Hofmeister MG, Weng MK ‐ CDC Yellow Book 2026 [link]
[5].  Summary of recommendations for the prevention of viral hepatitis during travel.  Committee to Advise on Tropical Medicine and Travel ‐ CCDR 2014;40-13:278-281 [link]
[6].  Prevention of hepatitis A virus infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020.  Nelson NP, Weng MK, Hofmeister MG, et al ‐ MMWR Recomm Rep 2020;69(5):1-38 [link]
[7].  Update: Recommendations of the Advisory Committee on Immunization Practices for use of hepatitis A vaccine for Postexposure prophylaxis and for preexposure prophylaxis for international travel.  Nelson NP, Link-Gelles R, Hofmeister MG, et al ‐ MMWR Morb Mortal Wkly Rep. 2018;67(43):1216-1220 [link]