Long-Term Effectiveness of Hep A Vaccination in Children Examined
Findings from a follow-up study in children who were vaccinated against hepatitis A virus support current recommendations and do not suggest a need for a booster vaccine. The study is published in Hepatology.
The effect of passively transferred maternal antibody to hepatitis A virus on seropositivity, after hepatitis A vaccination during infancy and early childhood is not well known, explained study authors. A team from the Centers for Disease Control and Prevention (CDC) studied levels of hepatitis A virus antibodies (anti-HAV) at intervals through age 15–16 among 3 groups of Alaskan native children. A total of 183 children received a 2-dose inactivated hepatitis A vaccination series at ages 6 months (Group 1), 12 months (Group 2), and 15 months (Group 3). They predicted seropositivity (anti-HAV ≥20 mIU/mL) 30 years after the second vaccine dose among the 3 groups. The children were randomized based on maternal anti-HAV status.
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The frequency of seropositivity among all children through age 10 was high with 100% seen in Groups 2 and 3, and >90% in Group 1. A decrease was seen thereafter through age 15–16 among Group 1 who initiated vaccination at age 6 months (50%–75%), and among maternal anti-HAV-positive children in Groups 2 and 3 (67%–87%), who initiated vaccination at 12 months and 15 months, respectively.
Overall, the predictive model showed that anti-HAV seropositivity should last for ≥30 years after vaccination in 64% of all study subjects. For those who were seropositive at 15–16 years, 84% were predicted to remain seropositive for ≥30 years. In general, most who intiated the vaccination series during early childhood maintained seropositivity through age 15–16. But seropositivity was less frequent for those starting vaccination at age 6 months and among maternal anti-HAV-positive children who started vaccination at 12 or 15 months.
Study authors concluded that study findings support current vaccine recommendations.
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