Levels of childhood immunisation coverage for the three-dose diphtheria, tetanus, and whooping cough (pertussis) are significantly lower than reported by individual nations or WHO/UNICEF estimates. In this era of target-oriented dispersal of funds for global initiatives, there is an urgent need for independent monitoring of health indicators which would be open to scrutiny. These are the conclusions of an Article published in this week's edition of The Lancet, written by Professor Christopher Murray, Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA and colleagues.
Over the past 30 years, substantial resources have been invested through global initiatives to scale up immunisation coverage. These include the WHO Expanded Programme on Immunisation (1974), a global goal programme to immunize against measles, polio, diphtheria, whooping cough, tetanus, and tuberculosis (1977), UNICEF's Universal Childhood Immunisation (UCI) initiative (1984), and the Global Alliance of Vaccines and Immunisations (GAVI) (launched 1999). However, there have been longstanding concerns that target-oriented and performance-oriented initiatives such as UCI and GAVI's immunisation services support (ISS) might encourage over-reporting. To investigate, the authors estimated the coverage of three does of diphtheria, tetanus, and whooping cough vaccine (DPT3) based on surveys using all the available data from 193 countries in the period 1986-2006.
The researchers showed that crude coverage of DTP3 based on surveys increased from 59% in 1986, to 65% in 1990, to 70% in 2000, to 74% in 2006. The authors say: "There were substantial differences between officially reported and survey-based coverage during UCI. GAVI ISS significantly increased the difference between officially reported coverage and survey coverage. Up to 2006, in 51 countries receiving GAVI ISS payments, 7.4 million addition children were immunized with DPT3 based on surveys compared with officially reported estimates of 13.9 million." Furthermore, on the basis of $20 received for each additional vaccinated child, the authors calculate that these 51 countries received overpayments of US $140 million from GAVI ISS; on the basis that they actually received $290 million when the survey data suggested they should only receive $150 million.
The authors propose that the target-oriented UCI campaign and the performance-based ISS payments used by GAVI have contributed to these reported coverage differences by incentivising over-reporting of immunisation. They say: "We believe that the only alternative for GAVI is a monitoring system that benchmarks coverage with periodic surveys, either as a condition or component of GAVI's support."
They conclude: "Globally, substantial resources are being directed towards increasing the effective coverage of interventions to improve population health. With this increase in aid flows for health comes the responsibility to ensure that these resources are being used cost-effectively and for their intended purpose…Measurement of immunisation coverage must be through more periodic gold-standard surveys that are integrated with improved administrative data if progress towards goals such as universal childhood immunisation is to be better measured and understood."
In an accompanying Comment, Dr David M Bishai, Johns Hopkins School of Public Health, Baltimore, MD, USA points out that while official country reports are not the gold standard, nor are the mothers' surveys used in the study to establish the vaccination status of the children. He says: "The pattern of results is suggestive, but not conclusive. Ample room for reasonable doubt should forestall an inquisition that diverts country vaccine-staff away from the important job of immunising children and maintaining accurate data. The real impact of Lim and colleagues' study should be to encourage researchers to finally try to understand why survey reports do not agree with administrative reports."
For Professor Christopher Murray, Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA please contact Jill Oviatt T) +1 206 897 2862 / +1 206 861 6684 E) cjlm@u.washington.edu / oviattj@u.washington.edu
Dr David M Bishai, Johns Hopkins School of Public Health, Baltimore, MD, USA T) +1 410-236-5908 E) dbishai@jhsph.edu / tmparson@jhsph.edu
For full Article and Comment, see: : http://press.thelancet.com/gavifinal.pdf
Journal
The Lancet