苏州地区b型流感嗜血杆菌结合疫苗对减少儿童住院肺炎有效性的观察性研究

  目的  评价接种不同剂次b型流感嗜血杆菌(Haemophilus influenzae type b, Hib)结合疫苗对儿童住院肺炎的保护效果(vaccine effectiveness, VE)。  方法  采用回顾性队列研究设计,以2018年出生并在苏州大学附属儿童医院住院的苏州地区常住儿童为研究对象,分别通过苏州大学附属儿童医院卫生信息系统和苏州市疾病预防控制中心疫苗登记数据库收集研究对象在2019年6月30日之前因肺炎住院的相关医疗信息以及Hib疫苗接种信息,比较不同剂次Hib疫苗接种组和未接种组的住院肺炎发生率,计算Hib疫苗保护效果。  结果  2018年1月1日-2019年6月30日苏州地区儿童Hib疫苗的首剂接种率为18.8%(10 080/53 753);住院肺炎发生率随接种剂次的增加而降低(χ2=-4.31, P < 0.001),其中1剂次Hib疫苗未显示保护效果,2剂次Hib疫苗已显示出保护趋势,但差异无统计学意义,接种3剂次及以上Hib疫苗的儿童住院肺炎发生率低于未接种组(RR=0.72, 95% CI: 0.59~0.89, P＜0.001),且可预防的住院肺炎发生率为1 514.8/105人年,保护效果为28%(95% CI: 11%~41%)。  结论  苏州地区3剂次及以上Hib疫苗接种可降低儿童因肺炎住院的发生率,建议推广儿童Hib疫苗接种工作,提高Hib疫苗覆盖率。     

Methodology and measurement of the effectiveness of Haemophilus influenzae type b vaccine: Systematic review

The use of the highly effective Haemophilus influenzae type b (Hib) conjugate vaccine has increased globally. We review the benefits and limitations of studies measuring Hib vaccine effectiveness (VE). We critically examine the case–control approach by assessing the similarities and differences in methodology and findings and discuss the need for future Hib VE studies. In the absence of good surveillance data, vaccine effectiveness studies can play an important role, particularly with the increasing use of pneumococcal vaccine that has not been well tested under field conditions in less developed countries. However, the effectiveness of Hib vaccine has been well documented so the need for future VE Hib studies is minimal.     

Estimating the vaccine-preventable burden of hospitalized pneumonia among young Mozambican children

Polysaccharide-protein conjugate vaccines against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae have proven efficacy against radiologically confirmed pneumonia. Measurement of pneumonia incidence provides a platform to estimate of the vaccine-preventable burden. Over 24 months, we conducted surveillance for radiologically confirmed severe pneumonia episodes among children <2 years of age admitted to a rural hospital in Manhiça, southern Mozambique. Study children were tested for HIV during the second year of surveillance. Severe pneumonia accounted for 15% of 5132 hospital admissions and 32% of in-hospital mortality among children <2 years of age. Also, 43% of chest radiographs were interpreted as radiologically confirmed pneumonia. HIV-infection was associated with 81% of fatal pneumonia episodes among children tested for HIV. The minimum incidence rate of radiologically confirmed pneumonia requiring hospitalization was 19 episodes/1000 child-years. Incidence rates among HIV-infected children were 9.3–19.0-fold higher than HIV-uninfected. Introduction of Hib and pneumococcal conjugate vaccines would have a substantial impact on pneumonia hospitalizations among African children if vaccine effects are similar to those observed in clinical trials.     

Vaccination with Haemophilus influenzae type b conjugate vaccine reduces bacterial meningitis in Morocco

Introduction

Haemophilus influenzae type b (Hib) is a leading cause of bacterial meningitis and pneumonia and can be prevented by Hib vaccine. We conducted a vaccine impact evaluation to support continued use of Hib vaccine in Morocco following introduction in 2007.

Methods

Bacterial meningitis surveillance data from 2004 to 2009 were obtained from 11 sentinel hospitals located in eight provinces and one prefecture in Morocco to examine Hi meningitis reporting for cases aged <5 years. We defined the years of 2004–2006 as the pre-vaccine period and 2008–2009 as the post-vaccine period and compared the mean annual number of confirmed Hi meningitis cases for these time periods using a Chi-square test. We calculated the minimum incidence of Hi meningitis during the evaluation period in Grand Casa Prefecture, where the catchment population could be estimated.

Results

From 2004 to 2009, 1844 suspected meningitis case-patients aged <5 years were reported; 354 (19.2%) were confirmed with bacterial meningitis, including 105 (29.7%) Hi cases. The mean annual number of confirmed Hi meningitis cases decreased by 75%, from 24 in the pre-vaccine period to 6 during the post-vaccine period (p < 0.001). Assuming Hi cases with unknown age were <5 years of age, the estimated minimum incidence of confirmed Hi meningitis in Grand Casa Prefecture decreased by 93%, from 15 cases per 100,000 children in the pre-vaccine period to 1 case per 100,000 children in the post-vaccine period.

Conclusion

Hib vaccine introduction likely significantly reduced the occurrence of Hi meningitis among children aged <5 years at the 11 sentinel hospitals included in this evaluation in Morocco, suggesting that continued use of Hib vaccine in Morocco would be beneficial.     

Supporting new vaccine introduction decisions: Lessons learned from the Hib Initiative experience

The introduction of Haemophilus influenzae type b (Hib) vaccine in developing countries has suffered from a long delay. Between 2005 and 2009, a surge in Hib vaccine adoption took place, particularly among GAVI-eligible countries. Several factors contributed to the increase in Hib vaccine adoption, including support provided by the Hib Initiative, a project funded by the GAVI Alliance in 2005 to accelerate evidence-informed decisions for use of Hib vaccine. This paper reviews the strategy adopted by the Hib Initiative and the lessons learned in the process, which provide a useful model to accelerate uptake of other new vaccines.     

Understanding the impact of Hib conjugate vaccine on transmission, immunity and disease in the United Kingdom

A rise in invasive Haemophilus influenzae type b (Hib) infections occurred 8 years after vaccine introduction in the United Kingdom. Aspects of Hib vaccine delivery unique to the United Kingdom have been implicated. The authors developed a fully age-structured deterministic susceptible-infected-resistant-susceptible mathematical model, expressed as a set of partial differential equations, to better understand the causes of declining vaccine effectiveness. We also investigated the consequences of the vaccine's impact on reducing Hib transmission for maintenance of immunity. Our findings emphasized the importance of maintaining high post-immunization antibody titres among age groups at greatest risk of invasive infections. In keeping with UK population-based estimates, low direct efficacy of immunological memory against disease was found, cautioning against over-reliance on evidence of priming alone as a correlate of population protection. The contribution of herd immunity to disease control was reinforced. Possible intervention strategies will be explored in subsequent work.     

Impact of routine vaccination with a conjugate Haemophilus influenzae type b vaccine

Based on a unique nationwide registration of vaccinated children, we studied the impact of routine Hib vaccination with special emphasis on vaccine uptake and adherence, vaccine effectiveness with respect to Hib meningitis, and indirect effects with respect to Hib meningitis among the unvaccinated children. Uptake and adherence was generally satisfactory. We estimated >97% effectiveness for all three doses of vaccine and observed herd-immunity in unvaccinated children comparable to a vaccine effectiveness of 94% 3.5 years into the programme. In conclusion, nationwide routine Hib vaccination is highly effective in protecting against Hib meningitis, and rapid achievement of herd immunity is possible with catch-up vaccination of older children.     

Impact of vaccination against Haemophilus influenzae type b with and without a booster dose on meningitis in four South American countries

To inform World Health Organization recommendations regarding use of Haemophilus influenzae type b (Hib) vaccines in national immunization programs, a multi-country evaluation of trends in Hib meningitis incidence and prevalence of nasopharyngeal Hib carriage was conducted in four South American countries using either a primary, three-dose immunization schedule without a booster dose or with a booster dose in the second year of life. Surveillance data suggest that high coverage of Hib conjugate vaccine sustained low incidence of Hib meningitis and low prevalence of Hib carriage whether or not a booster dose was used.     

Estimating the Haemophilus influenzae type b (Hib) disease burden and the impact of Hib vaccine in Fiji

AIMS: To estimate Haemophilus influenzae type b (Hib) disease burden in Fiji in children under the age of 5 years (under-5s) prior to vaccine introduction. To compare estimates from WHO's Hib rapid assessment tool (RAT), with that from decline in disease after vaccine introduction. METHODS: Laboratory data (meningitis), hospitalization and mortality data (pneumonia and meningitis) before and after Hib vaccine introduction were collected. The RAT protocol provides two independent estimates of pre-vaccine disease burden (one based on meningitis incidence laboratory data and the other based on mortality statistics). A third estimate uses the decline in disease following vaccine introduction. RESULTS: The decline in meningitis hospitalizations implies a pre-vaccine Hib meningitis incidence of 66 per 100,000 in under-5s. This compares with a pre-vaccine RAT estimate of Hib meningitis incidence of 84 per 100,000 (for 1992-1993). The RAT estimated the total annual pre-vaccine Hib burden (meningitis plus pneumonia) at 476 cases and 36 deaths per year ("meningitis incidence method") and 70 cases and 5 deaths ("child mortality method"). Hib vaccine led to declines of 32% (95% confidence interval (CI)=11-48%), and 78% (95% CI=22-94%) for all under-5s meningitis hospitalizations and deaths, respectively. There was no similar consistent decline in pneumonia hospitalizations or deaths after vaccine introduction, except for a statistically significant reduction in pneumonia mortality in children aged under 1 year. CONCLUSIONS: Hib disease constitutes an important burden on the health of Pacific children that can be rapidly reduced with Hib vaccine. In this setting, routine morbidity statistics (comparing pre-and post-vaccine) provided an estimate of Hib meningitis burden which is broadly similar to that of the Hib RAT, suggesting that both might be valid ways to estimate Hib meningitis incidence. However, Hib pneumonia burden could not be estimated from routine statistics.     

Effectiveness of Haemophilus influenzae b conjugate vaccine on childhood pneumonia: a case-control study in Brazil

BACKGROUND: The conjugate Haemophilus influenzae type b (Hib) vaccine has been highly efficacious in reducing type b H. influenzae meningitis. However, information is limited about its impact on childhood pneumonia after vaccine introduction into the routine programme. This study evaluated the effectiveness of Hib conjugate vaccine in the reduction of community-acquired pneumonia among infants in Central Brazil. METHODS: A matched case-control study was built into an ongoing prospective population-based surveillance of pneumonia, enrolling 1293 participants between May 2000 and August 2001. Cases (n = 431) were children 相似文献