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Updated: Jun 12, 2026

Assessing Respiratory Immune Responses to Haemophilus Influenzae
Published on: June 29, 2021
[A prospective cohort study on community children vaccinated with Haemophilus influenzae type b]
Xiao-hua Qian1, Chuan-qing Wang, Qi-rong Zhu
1Hongkou District Center of Disease Control and Prevention of Shanghai Municipal, Shanghai 200082, China.
Objective:
To evaluate the epidemiological effect of Haemophilus influenzae type b conjugate vaccine (Hib).
Methods:
Prospective Cohort Study was conducted to detect carrier rate of Hi in unvaccinated and vaccinated children by bacteria culture and Nest-PCR. Carrier rate of Hi and the incidence of lower respiratory tract infection in two groups children were analysed.
Results:
The carrier rate of Hib in two groups children was very lower. The positive rate of NTHi in unvaccinated children was higher than vaccinated children significantly, which was mainly happened in the Children of 2-3 years old. The incidence of lower respiratory tract infection in unvaccinated children was higher than vaccinated children obviously. The protective effect of Hib vaccine against bronchitis was over 90%. The incidence of bronchitis of Hi culture positive was higher than that of Hi culture negative significantly.
Conclusion:
Children's bronchitis is related to the Hi carrier rate. To inoculate Hib vaccine can reduce the carrier rate of Hi and the incidence of bronchitis.
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Observational studies are those where the researcher does not intervene but rather observes natural variations. They include cross-sectional, cohort, and case-control studies.
