Elsevier

Public Health

Volume 123, Issue 1, January 2009, Pages 74-77
Public Health

Original research
Assessment of the need for universal BCG vaccination of children in Taipei

https://doi.org/10.1016/j.puhe.2008.10.002Get rights and content

Summary

Objectives

This retrospective study evaluated epidemiological trends in childhood tuberculosis (TB), and examined whether or not universal vaccination should be retained in Taipei City.

Study design

Data of all recorded cases of TB among children from 2001 to 2005 were obtained from the TB Registry Database.

Methods

The trend in TB incidence among children was analysed. Tuberculin skin tests were also performed to estimate the prevalence and annual risk of TB infection in second-grade school children.

Results

The average annual incidence of meningeal TB in children aged 0–4 years was 0.76 per 10 million general population for the previous 5 years. Among cases of pulmonary TB, smear-positive rates increased from 17.88 to 18.54 per 100,000 population during the study period. In second-grade children, the annual risk of TB infection was 1.01% in 2005, with an increasing trend over the study period.

Conclusions

The findings indicate that one of the criteria established by the International Union against Tuberculosis and Lung Disease to discontinue universal BCG vaccination has been met in Taipei. Despite this favourable condition, considering that the sputum-smear-positive rates were as high as 20.11 per 100,000 population, universal BCG vaccination should be retained until the risk of exposure decreases.

Introduction

Bacillus Calmette-Guerin (BCG) vaccine has been widely administered around the world for over 75 years, and more than 70% of the world's children are currently vaccinated. However, it is the most controversial vaccine in current use.1 Inconsistent results from several controlled trials of BCG vaccine have cast doubts over its efficacy. Some studies have demonstrated that BCG vaccine gives good protection against TB,2 but other studies have shown very little protection.3 Moreover, variation in the protective effect of the vaccine has been observed not only between trials but also between different sites of disease. A greater protective effect has been observed against meningitis and miliary disease than against other forms of TB. This trend was corroborated by the results of a meta-analysis of published BCG vaccination trials, in which BCG vaccine was found to be 50% effective in the prevention of pulmonary TB in adults and children, and 80% effective in the prevention of disseminated and meningeal TB.4

Based on these reassuring data on the effectiveness of BCG vaccine in the prevention of severe TB in children, vaccination continues to be recommended by the World Health Organization (WHO) as part of an infant's immunization programme and is practised by the majority of countries in the world today.5 However, policies differ greatly between countries. In fact, BCG vaccination is only recommended for high-risk groups in the USA and the Netherlands.5 In some countries with low rates of TB, such as Switzerland and Sweden, universal BCG vaccination was discontinued many years ago.6, 7 Universal BCG vaccination has been discontinued in the UK since 2005 in favour of selective vaccination of high-risk groups,8 and Japan has also re-appraised the value of routine BCG vaccination in the prevention of TB.9 These policy differences are related to differences in opinion about the efficacy of the vaccine and local variations in TB epidemiology.

Universal BCG vaccination of newborns and revaccination of children at 7 years of age have been performed in Taipei since 1951 and, according to citywide statistics, more than 95% of children were vaccinated before primary school during the study period. However, no information is available regarding the effectiveness of the current BCG programme in Taiwan. BCG vaccination generally induces tuberculin sensitivity, and thus its universal administration would render subsequent TB skin tuberculin testing less useful as a tool in the diagnosis of TB. These problems have stimulated a debate in Taipei regarding whether or not universal vaccination should be discontinued. To address this debate, the present study was designed to explore the current situation of childhood TB in Taipei, and to compare this with the criteria established by the International Union against Tuberculosis and Lung Disease (IUATLD) for discontinuation of universal BCG vaccination. The results offer a reference for policy making regarding stopping or modifying the BCG vaccination programme in Taipei.

Section snippets

Incidence data and population

The National TB Registry Campaign was only started recently in Taiwan, so full information about the incidence of tuberculosis in Taipei is only available from 1998. For the purpose of this analysis, a child was defined as a person under 15 years of age, and an adult was defined as a person aged 15 years or older. Data for all 10,526 newly diagnosed and verified TB cases recorded from 2001 to 2005 were obtained from the National TB Database. Of these cases, 10,408 (98.88%) were adults and 118

Incidence rate of childhood TB

Table 1 shows the case rates for children by age and time period. From 2001 to 2005, a total of 118 childhood TB cases were reported to the National TB Registry, and the average annual incidence rate of childhood tuberculosis was 4.82 cases per 100,000 during the study period. Overall, case rates in children decreased from 6.42 per 100,000 population in 2001 to 4.61 per 100,000 population in 2005 (P < 0.05, trend test). This represented a 28.19% decrease in the case rate (Fig. 1). Among children,

Discussion

The most striking finding of this study was that the best use of BCG vaccination appears to be good prevention of life-threatening forms of meningeal TB in younger children. Between 2001 and 2005, there was only one case of meningeal TB among children aged 0–4 years (in 2002). The average annual incidence of meningeal TB among children aged 0–4 years was 0.76 per 10 million general population over the previous 5 years, which meets the IUATLD criterion of a case rate lower than one per 10

References (22)

  • M. Rahman et al.

    Economic evaluation of universal BCG vaccination of Japanese infants

    Int J Epidemiol

    (2001)
  • Cited by (2)

    • Childhood tuberculosis: Epidemiology, diagnosis, treatment, and vaccination

      2013, Pediatrics and Neonatology
      Citation Excerpt :

      The Mantoux test is the recommended standard tuberculin test.18 Tuberculin is commercially available in 1, 2, and 5 Tuberculin Unit (TU) PPD (purified protein derivative, RT23 equivalent) forms.19,20 For the test, it is important to raise a wheal of approximately 6 mm after the intradermal injection.

    View full text