[Serologic investigation of HBV in 302 patients who had a history of smallpox].

This paper provides serologic investigation of HBV in 302 persons who had a history of smallpox in Zhumadian County. The results showed that the HBsAg positivity rate (1.3%) was significantly lower than those of the control group 1 (8.3%) and 2 (8.6%) (P less than 0.001). The HBsAg positivity rate between the two control groups had no significant difference (P greater than 0.05). The HBV infection rate (19.2%) was also lower than those of control group 1 (47.7%) and 2 (51.3%) (P less than 0.001). There was not much difference between the two control groups. The determination of cellular immunity showed that the rosette positivity rate (75.93%) and lymphocyte conversion rate (70.39%) of the patients' group were higher than those of control group 1 (62.3% and 52.9%) and 2 (60.93% and 55.3%). It may suggested that patients having had smallpox might have enhanced cellular immunity which might interfere with HBV infection.