Reflections on 30 years of the International Study of Asthma and Allergies in Childhood (ISAAC) and the Global Asthma Network (GAN)

Professor Emeritus Innes Asher, University of Auckland, New Zealand

ISAAC, formed in 1991, was innovative in developing methodology for measuring asthma prevalence in children which was straightforward, standardised, low cost and repeatable using questionnaires, and could be used in all parts of the world. Collaborators in centres in all regions of the world (233 centres in 97 countries) engaged in ISAAC over the next 20 years, enabling, for the first time, a global picture of asthma and changes in prevalence, severity, and environmental factors. In several regions asthma was more common than previously thought, especially in low- and middle-income countries (LMICs), this data informing public health policy. The association of asthma with atopy was weak especially in LMICs.

Asthma was identified as an important noncommunicable disease (NCD) at the first UN Summit on NCDs 2011, and the first Global Asthma Report (GAR) was launched there as a collaboration between the International Union Against Tuberculosis and Lung Disease (The Union) and ISAAC. Out of this collaboration GAN was established and has since published GARs – in 2014, 2018 and 2022. GAR 2022 was written by 97 authors from 31 countries.

GAN built on the unique network of collaborators built by ISAAC. GAN has completed studies of asthma prevalence, severity and environmental factors in adults and children and changes over time in children confirming that asthma remains a large worldwide public health problem. Importantly, we have shown that large numbers of people in the world lack access to affordable quality-assured essential asthma medicines. Addressing this lack is the subject of this symposium.


  • Enarson DA. Fostering a spirit of critical thinking: the ISAAC story. Int J Tuberc Lung Dis 2005; 9(1): 1.
  • Asher MI, García-Marcos L, Pearce NE, Strachan DP. Trends in worldwide asthma prevalence. Eur Respir J 2020; 56(6):2002094.
  • Asher MI, Rutter CE, Bissell K, Chiang CY, El Sony A, Ellwood E, Ellwood P, García-Marcos L, Marks GB, Morales E, Mortimer K, Pérez-Fernández V, Robertson S, Silverwood RJ, Strachan DP, Pearce N and the Global Asthma Network Phase I Study Group. Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional study. Lancet 2021;398(10311):1569-1580.
  • The Global Asthma Report. Int J Tuberc Lung Dis 2022; 26: S1–S102.


GAN gratefully acknowledges funding from the University of Auckland and Wellcome (Grant number 203919/Z/16/Z) as well as sponsorship from AstraZeneca and GlaxoSmithKline that has helped to make the GAN Symposium 2024 possible. We thank the speakers and the organisations they represent for their contributions including securing their own funding to enable their participation. The Symposium programme was developed independently by the GAN Steering Group.

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