RESUMEN
BACKGROUND: Blood and plasma donor screening for hepatitis B virus (HBV) DNA, HBV surface antigen (HBsAg), and antibodies to surface (anti-HBs) and core (anti-HBc) antigens allows identification of individuals who acquired HBV despite previous HBV vaccination. METHODS: Of 14 HBV acute infection donor panels (HBV-DNA-positive/anti-HBc-negative), 6 donors were previously vaccinated (anti-HBs+). We investigated the differences in viral kinetics and immune responses in vaccinated and nonvaccinated individuals. Serial specimens were characterized for HBV DNA and serological markers and 39 cytokines. RESULTS: The rate of viral load increase was blunted, and virus was cleared more rapidly in vaccinated individuals (P = .004). In unvaccinated individuals, induced protein 10 (IP-10), interleukin 10 (IL-10), macrophage inflammatory protein 1ß (MIP-1ß), and soluble interleukin 2Rα (sIL-2Rα) levels were commonly elevated at the time of peak viremia. In contrast, vaccinated individuals had earlier peaks in IL-10 and IP-10 responses that occurred at much lower viral loads and coincided with anamnestic anti-hepatitis B surface (HBs) responses and clearance of viremia. CONCLUSION: There is earlier engagement of innate and adaptive immunity in infected subjects with previous vaccination, possibly explaining suppressed viremia in vaccine breakthrough infections. Although breakthrough infections occur in partially protected vaccine recipients, vaccination likely contributes to early control of replication, limiting immune activation and preventing development of clinically significant acute and chronic HBV infection.