Aids Weekly Plus
Researchers report that a two-dose regimen of hepatitis A vaccine and a three-dose regimen were equally effective after more than 14 years in protecting Alaska Native study participants ages 12 to 24 years.
The study compared levels of hepatitis A antibody (anti-HAV) results in two groups. The first group of 101 Alaska Natives between the ages of 12 and 24 initiated two-dose vaccination (720 ELU) for hepatitis A more than five years earlier; a 24-person subgroup received vaccination between the ages of three and six. Researchers compared results for this subgroup with a similar second group who received a three-dose vaccination (360 ELU).
Researchers found no significant difference between the groups in “anti-HAV geometric mean concentration (GMC)” according to when immunization was started (ages 1, 2, 3 to 6, and 7). Those who received vaccination at one to two years consistently had the lowest GMC levels. Eleven years after the second dose, GMC levels for 5 percent of the two-dose group were not seroprotective.
The two- and three-dose participants also had similar GMC levels 10, 12, and 14 years after vaccination. All two-dose participants and almost all three-dose participants who could be evaluated, continued to have protection from hepatitis A 10, 12, 14, and 15 years after the second dose. The study also found that the three-dose participants were protected after 17 years.
Study authors recommended continuing evaluation to determine if and when hepatitis A boosters will be needed.
The full report, “Duration of Protection Against Hepatitis A for the Current Two-dose Vaccine Compared to a Three-dose Vaccine Schedule in Children,” was published online in the journal Vaccine (2013; doi:10.1016/j.vaccine.2013.02.048).