Haemophilus influenzae Type b conjugate Vaccine(Beijing Luzhu Biopharma)

Objective: To evaluate the immunity persistence five years later after immunization with Haemophilus influenzae type b (Hib) conjugate vaccine in healthy infants/children aged 3 months to 5 years in China. Methods: The children were subjects who completed the whole-schedule immunization in the phase Ⅲ clinical trial in Lianshui county of Jiangsu povince was selected for the collection of blood samples at 5 years after vaccination from November to December, 2019. The enzyme-linked immunosorbent assay (ELISA) was used to detect Hib polyribosyl-ribitol-phosphate antibody (anti-Hib-PRP), and the long-term/short-term protection rate, geometric mean concentration (GMC) and geometric mean concentration increase fold (GMFI) of serum anti-Hib-PRP were calculated. Results: A total of 580 children were enrolled in this study, of which 158, 207 and 215 belonged to 3-5 month age group, 6-11 month age group and 1-5 year age group, respectively. The short-term (≥0.15 μg/ml)/long-term (≥1.0 μg/ml) protection rates of serum anti-PRP in the three groups after immunization were 89.24%, 90.34% and 98.60%, respectively; the GMC were 3.95 μg/ml, 3.11 μg/ml and 10.01 μg/ml respectively, and the GMFI were 29.04, 11.01 and 3.26 respectively. Conclusions: Hib conjugate vaccine can still have good immunogenicity after 5 years of primary immunization in healthy infants/children aged 3 months to 5 years in China.

Children living with Human Immunodeficiency virus (HIV; CLH) have special vaccine needs. Determinants of household-level uptake of vaccines need to be examined in high-risk families with CLH. We previously conducted a study on the impact of Haemophilus influenzae type b conjugate vaccine and pneumococcal conjugate vaccine (PCV-13) in 125 HIV-affected families and 47 HIV-unaffected families in West Bengal. We then interviewed 99 of these 172 families who had participated in the study to understand the household-level factors that determine vaccine uptake. Sixty-four of the 99 families had one or more CLH. Within these 64 families, 30% of CLH had missed vaccines under the universal immunization program (UIP), compared to only 6% of HIV-uninfected children (HUC) (p = .001). Maternal HIV positivity in a family increased risk of missing UIP vaccines nearly five times (4.82, p = .001). Almost all families accessed UIP vaccines at local primary vaccination centers, but 14% of families experienced stigma due to HIV and avoided getting one or more vaccine doses. In contrast, in our study, 100% of HIV-affected families actively sought PCV-13 and HibCV, despite having to travel. Factors that influenced uptake included awareness generation and activation by an outreach worker and availability of vaccines on pick-up days for anti-retroviral therapy. Eighty-six percent of families strongly recommended PCV-13 to other families. To conclude, while we found that CLH have barriers to getting vaccinations, a program designed to take into consideration the obstacles that HIV-affected families face showed a high rate of vaccine uptake.