Prevalence and clinical features of patients with concurrent HBsAg and anti-HBs: Evaluation of the hepatitis B research network cohort

The prevalence of concurrent HBsAg and anti-HBs in plasma of persons with chronic hepatitis B virus (HBV) infection is variable and its clinical significance enigmatic. We examined the prevalence and clinical and virological features of concurrent HBsAg and anti-HBs in children and adults with chronic HBV infection living in North America. A total of 1462 HBsAg positive participants in the Hepatitis B Research Network paediatric and adult cohorts were included (median age 41 (range 4-80) years, 48% female, 11% white, 13% black, 73% Asians). Only 18 (1.2%) were found to be anti-HBs positive (≥10 mIU/mL) at initial study evaluation. Distributions of sex, race, HBV genotype and ALT were similar between participants with and without concurrent anti-HBs. Those who were anti-HBs positive appeared to be older (median age 50 vs 41 years, P =.06), have lower platelet counts (median 197 vs 222 × 103/mm³, P =.07) and have higher prevalence of HBeAg (44% vs 26%, P =.10). They also had lower HBsAg levels (median 2.0 vs 3.5 log₁₀ IU/mL, P =.02). Testing of follow-up samples after a median of 4 years (range 1-6) in 12 of the 18 participants with initial concurrent anti-HBs showed anti-HBs became undetectable in 6, decreased to <10 mIU/mL in 1 and remained positive in 5 participants. Two patients lost HBsAg during follow-up. In conclusion, prevalence of concurrent HBsAg and anti-HBs was low at 1.2%, with anti-HBs disappearing in some during follow-up, in this large cohort of racially diverse children and adults with chronic HBV infection living in North America. Presence of concurrent HBsAg and anti-HBs did not identify a specific phenotype of chronic hepatitis B, nor did it appear to affect clinical outcomes.