Among 273 household contacts of HBsAg-positive participants, 39 (14%) had positive test results for HBsAg, 83 (30%) had negative test results for HBsAg and positive results for anti-HBc (immune because of resolved infection), and 101 (37%) were anti-HBs-positive and anti-HBc-negative (immune because of vaccination). Here, KRT88P is linked to infection.