Long-term immunity in young adults after a single dose of inactivated Hepatitis A vaccines

Nadav Orr*, Eyal Klement, David Gillis, Tamar Sela, Raid Kayouf, Estela Derazne, Itamar Grotto, Ran Balicer, Michael Huerta, Lisa Aviram, Ruhama Ambar, Yoram Epstein, Yuval Heled, Dani Cohen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


We evaluated in a prospective study the immune response of naïve subjects to a single dose of inactivated Hepatitis A vaccine. Ninety-seven percent of the vaccinees sero-converted 1 month after vaccination and 93% were still positive 2 years later. All of the vaccinees had a strong booster response 2 years after the single dose. Avaxim was more immunogenic than Vaqta for the primary dose (p = 0.01 for sero-positivity, p < 0.001 for antibody level) but no differences were found after boosting with Avaxim. Performance of intense physical activity during the first month after a single vaccine dose was associated with lower antibody levels (p = 0.004). This study indicates that a single dose of inactivated HAV vaccine elicits protective immune memory for at least 2 years.

Original languageAmerican English
Pages (from-to)4328-4332
Number of pages5
Issue number20
StatePublished - 15 May 2006
Externally publishedYes


  • Hepatitis A vaccine
  • Long term protection
  • Single dose


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