Social Science & Medicine 57 (2003) 97–112 Trust, learning, and vaccination: a case study of a North Indian village Jishnu Das a, *, Saumya Das b a Development Research Group, The World Bank, MSM MC3-311 DECRG, Washington, DC 20433, USA b Harvard Medical School and Massachusetts General Hospital, Cambridge, MA, USA Abstract For US $17 a child can be immunized against six major illnesses. Even at this price, a country such as India would have to spend half its health budget on providing vaccinations. Given the wide variation in immunization costs it may be possible to decrease this cost to more sustainable levels, but to do so we need to arrive at a more thorough understanding of factors affecting household demand for vaccination. Using data on vaccination and pre-natal care collected by the authors in the Garhwal region of India, we explore one aspect of the demand for vaccination in some detail. We show that informational constraints play an important role in the household decision to seek vaccination, and moreover, that learning about the efficacy of vaccinations only through empirical observation may be hard even in environments with variation in vaccination and the high incidence of vaccine-preventable diseases. We argue that when learning about vaccination is inefficient, households use concurrent interventions with easily observable outcomes to evaluate the veracity of a provider’s claim regarding preventive care. Hence, the success of immunization programs becomes crucially linked to the success of parallel programs by the same provider. r 2003 Elsevier Science Ltd. All rights reserved. Keywords: Vaccination; Information; Learning; Trust; India Introduction Each year more than 1.6 million deaths and 16% of the total burden of disease in children under 5 years of age can be attributed to diseases preventable under the Expanded Program on Immunization (World Bank, 1993). Nevertheless, during the 1990s, the proportion of fully immunized children declined from 80% in 1990 to 74% in 1998 (WHO, 2000) with a consequent widening of the immunization gap between high- and low-income countries. 1 Such low rates of immunization have typically been associated with supply constraints, primarily in terms of budgetary under-allocation and ground level implemen- tation of official policies. For example, it is argued that: ‘‘For only $17 per child, we can provide lifetime protection against the six historical scourgesy’’ 2 and presumably therefore, the financing issue can be easily solved. But can we really interpret this statement as indicative of the low costs of vaccination? For India, the $17 per fully immunized child represents an extremely high share of both government and private expenditure on health. For the government, the annual costs of immunization using this figure and a *Corresponding author. Tel.: +1-202-473-2781; fax: +1- 202-522-1154. E-mail address: jdas1@worldbank.org (J. Das). 1 This decline is not due to changes in the number of illnesses a fully immunized child must be vaccinated against. While high- income countries have seen an increase in the coverage of measles, polio and DPT vaccines from 1990 to 1999, coverage has actually decreased for African and Asian regions during the (footnote continued) same time period (for instance, coverage in the Asian region for DTP fell from 94% to 76%, WHO, 2000 vaccination global summary). 2 Brundtland, G. H., Director-General, WHO quoted in Development News, January 31–February 4, 2000. 0277-9536/03/$ - see front matter r 2003 Elsevier Science Ltd. All rights reserved. PII:S0277-9536(02)00302-7