Abstract: Objective To study the effect of cytomegalovirus infection on the primary immune response to hepatitis B vaccine of infants.Methods A total of 148 full-term newborns (not vaccinated with the second dose of hepatitis B vaccine) were selected from January 2019 to January 2020 in our hospital. Among them, 74 children were diagnosed as human cytomegalovirus (HCMV) infection in our hospital were included in the observation group, and 74 newborns without HCMV infection were selected as the control group.The serum levels of anti-HBs, IL-2 and IL-6 in the two groups were detected after the whole course of immunization. The levels of cellular immune indexes (CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺) were detected. Results The serum levels of anti-HBs and IL-2 in the observation group were lower than those in the control group (P<0.05), while the serum IL-6 level was higher than that in the control group (P<0.05);The primary immune response rate of observation group (67.57%) was lower than that of control group (85.14%) (P<0.05).The levels of CD3⁺, CD4⁺, CD4⁺/CD8⁺ in the observation group were lower than those in the control group (P<0.05), and the level of CD8⁺ in the observation group was higher than that in the control group (P<0.05).Conclusion Combined with cytomegalovirus infection will make the immune function of newborns in imbalance and inhibition state, which will lead to the decrease of immune response rate and the intensity of immune response to hepatitis B vaccine.

Key words: Cytomegalovirus, Hepatitis B vaccine for children, Primary immune response, Cellular immunity index