Table of Contents

HK J Paediatr (New Series)
Vol 6. No. 2, 2001

HK J Paediatr (New Series) 2001;6:128

Proceedings of The First Current Topic in Infectious Diseases

Invasive Haemophilus Influenzae b Disease: Overview and Disease Burden in Hong Kong

YL Lau


HK J Paediatr (new series) 2001;6:127-132

Proceedings of The First Current Topic in Infectious Diseases: Consensus Meeting on Conjugate Vaccines of the Center of Infection
Faculty of Medicine, The University of Hong Kong (Selected Abstracts)

In a position paper on Hib conjugate vaccine, WHO made the following qualified statement: "In view of the demonstrated safety and efficacy of the Hib conjugate vaccines, Hib vaccine should be included, as appropriate to national capacities and priorities, in routine infant immunization programmes." This statement highlights the two major barriers to the implementation of routine infant Hib immunization in Asia: the cost of Hib vaccine and its administration which has to be accommodated by "national capacities"; and the absolute disease burden of Hib diseases and its relative burden in the broader context of total disease burden, which will determine the "national priorities". The disease burden of Hib diseases varies greatly from one country to another in Asia but on a whole may be less than that in North America. Better documentation of burden of disease is not just of academic interest but indispensable as part of a very complex strategy to introduce novel but relatively expensive vaccines, such as Hib and pneumococcal conjugate vaccines. Currently, the high-income countries in Asia should address this issue of whether or not to introduce routine Hib immunization of infants because their "national capacities" could easily accommodate the cost of the vaccine and its administration; and even if the incidence of Hib disease in these countries is low, the benefits of such routine immunization could be substantial because the indirect medical costs and long-term treatment costs of Hib morbidity increase with per capita gross national product (GNP). For example, in Hong Kong Special Administrative Region of China, where the estimated incidence of Hib meningitis and bacteremic pneumonia is only about three per 100,000 children aged under five years; there would still be about 10 cases per year, with perhaps one death and two children suffering sustained permanent neurological sequelae but surviving for decades, and thus in need of long-term health care. The net Hib immunization programme cost could be offset by the savings made in not having to provide care for these handicapped children for the rest of their lives as well as the life saved. However, for low-income countries, the absolute cost involved will be high enough to prohibit implementation of routine Hib infant immunization, despite the demonstrated cost-effectiveness of such programs.

Method and Process of Consensus Building

The consensus meeting on Consensus meeting on conjugate vaccines was held on February 17, 2001, as the first current topic in infectious diseases that was organized by the Centre of Infection, the University of Hong Kong. A panel of experts from the fields of Internal Medicine, Clinical Microbiology, Internal Medicine, Paediatrics and Public Health were provided with the latest scientific papers1-8 and were invited to speak and discuss on various aspects concerning the topic.

After the formal presentation, panel discussion was held. All speakers, invited discussants from various aspects of the medical fields and audiences actively participated in the discussion with further elaboration on issues around S. pneumoniae and H. influenzae disease burden, antimicrobial resistance and conjugate vaccine.

Finally, conclusions were drawn on the basis of the current scientific information and views expressed by the panel and other participants. Drafts in progress and final copies of the manuscript were distributed to panel for comments before submission for publication.


Consensus Panel Members

Daniel CS Chiu, Pediatrician in private practice
Susan SS Chiu, Assistant Professor, Department of Paediatrics, The University of Hong Kong
CB Chow, Consultant, Department of Paediatrics, Princess Margaret Hospital
PL Ho, Associate Professor, Department of Microbiology, The University of Hong Kong
YL Lau, Chair Professor in Paediatrics, Department of Paediatrics, The University of Hong Kong
CW Leung, Consultant, Department of Paediatrics, Princess Margaret Hospital
Dominic NC Tsang, Consultant, Department of Clinical Pathology, Queen Elizabeth Hospital
Kenneth WT Tsang, Associate Professor, Department of Medicine, University of Hong Kong.
Thomas HF Tsang, Community Physician, Department of Health
Samson SY Wong, Assistant Professor, Department of Microbiology, University of Hong Kong.
YH Yang, Professor, Beijing Children's Hospital, Beijing
KY Yuen, Chair Professor in Infectious Diseases, Department of Microbiology, The University of Hong Kong


Consensus Statements

Disease burden of paediatric Haemophilus influenzae type b infections in Hong Kong

1. The incidence of Haemophilus influenzae type b (Hib) diseases in Hong Kong appears to be low. Multiple confounding factors, such as prior antibiotic usage, might be the causes for the apparent low recorded prevalence.

2. Further study to collect epidemiological data in Hong Kong would be difficult due to the following factors:

a) Some children might have been given Hib vaccination on an individual basis.

b) There are quite a number of patients taking antibiotics prior to collection of specimens for cultures and the recovery rate of any microorganisms in these situations is relatively low.

3. Gaps in existing data should be addressed in future studies using new research methodology, such as the WHO rapid assessment tool.

Use of conjugate Haemophilus influenzae type b vaccine

1. Conjugate Hib vaccine has proven safety and efficacy in prevention of invasive Hib disease.

2. Thorough cost-effective/benefit/utility analysis and comparison of existing program would be very helpful in supporting recommendation for universal vaccination in this locality. Broader discussion/consultation on what constitute the "acceptable" cost is required.

Disease burden of pneumococcal infections in Hong Kong

1. Disease burden of pneumococcal disease is still unclear and further study would be needed for different at-risk groups.

2. Penicillin-resistant and multiple antibiotic-resistant pneumococci are a major problem in Hong Kong.

Use of conjugate pneumococcal vaccine

1. The heptavalent conjugate vaccine provides good coverage of the serotypes causing invasive pneumococcal disease in Hong Kong at present.

2. Conjugate pneumococcal vaccine is effective in decreasing vaccine strain carriage, and preventing invasive pneumococcal disease in young children from published experience.

Acknowledgement

The meeting was sponsored by the Hong Kong Paediatric Foundation.


References

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