Long-term immunity in young adults after a single dose of inactivated Hepatitis A vaccines.
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.
Center for Vaccine Development and Evaluation, IDF, Israel. naorr@012.net.il
Nadav
N
Orr
Eyal
E
Klement
David
D
Gillis
Tamar
T
Sela
Raid
R
Kayouf
Estela
E
Derazne
Itamar
I
Grotto
Ran
R
Balicer
Michael
M
Huerta
Lisa
L
Aviram
Ruhama
R
Ambar
Yoram
Y
Epstein
Yuval
Y
Heled
Dani
D
Cohen
D000293:Adolescent; D000328:Adult; D035922:Hepatitis A Antibodies / Q000096:biosynthesis*; D022362:Hepatitis A Vaccines / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D015164:Vaccines, Inactivated / Q000276:immunology*
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D015164:Vaccines, Inactivated