Predictors of impaired immune response to hepatitis B vaccine in children under 5 years of age at Sialkot,Pakistan

Objective: to find out the predictors of impaired immune response to primary hepatitis b vaccine in children (aged ˂ 5 years) design and setting: this cross-sectional study was conducted between may and june,2015 after getting approval from ethics committee of govt. sardar begam teaching hospital,sialkot,pakistan. methodology: sixty (60) hepatitis b vaccinated children (aged ˂ 5 years) having endorsed epi record were recruited from different areas of district sialkot using 2-stage cluster sampling technique. documentation of baseline information was followed by blood sampling for estimation of anti-hbs titer though elisa kit. results: of 60 blood samples,56 i.e. 93.3% (excluding hemolysed samples) showed sero-conversion while 27 (48.2%) had sero-protection. however,comparatively higher sero-protection rate (60%,n = 12) was found in females. descriptive statistics revealed mean (m) immune response of 80.76 (sd = 117.34) iu/l. significant decrease in the response was observed with increasing age group (p = 0.0001). a malnourished child was at 5 times more risk of lowered antibody concentration than well-nourished children (rr = 5.35; 95% ci: 2.126 – 13.479; p = 0.0001). similarly,the possibility of poor response was approximately 5-fold in a child of smoker parents (rr: 4.84; 95% ci: 2.174 – 10.783; p = 0.0001) compared to non-smokers. however,insignificant association was found between immunity and socio-economic status (p ˂.05). conclusion: long post-vaccination time,malnutrition,and smoker parents are the predictors for impaired immune response to hepatitis b vaccine in the children. the risk factors deserve public awareness for increased anti-hbs titer. © 2017,pakistan pediatric journal. all rights reserved.