News Release

Timing of children's vaccinations varies widely between and within countries

Peer-Reviewed Publication

The Lancet_DELETED

Children's vaccinations are often delayed until well after the recommended ages in low-income and middle-income countries, leaving many children exposed longer than they should be. The issues are discussed in an Article published Online First and in an upcoming edition of The Lancet, written by Dr Colin Sanderson and Dr Andrew Clark, London School of Hygiene and Tropical Medicine, UK. The study was funded by WHO's initiative for Vaccine Research.

The authors used data for nearly 218,000 children from Demographic Health Surveys from 45 low-income and middle-income countries*, taken between 1996 and 2005, for their analysis. The surveys provided vaccination data based on vaccination card and interviews with mothers. The authors then devised an index that combines and summarises measures of coverage and delay.

They found that for vaccinated children, the typical delay in the 45 countries was 2.3 weeks for Bacille Calmette-Guérin (BCG); 2.4 weeks for diphtheria, tetanus and pertussis (DTP1); 2.7 weeks for measles-containing vaccine (MCV); and 6.2 weeks for DTP3. However when looking at the 12 countries with the longest delay for each type of vaccination (a different 12 for each vaccination ), at least 25% of the vaccinations were administered more than 10 weeks late for BCG, eight weeks for DTP1, 11 weeks for MCV1, and 19 weeks for DTP3. Data quality tended to be poorer in countries with long delays, and vaccination after the recommended age could have been the result of worthwhile if belated efforts to increase coverage. However the survey data suggested that in five countries (Chad, Cambodia, Mali, Mauritania and Niger) there were both long delays and low coverage. Variation in the amount of delay within each country was also substantial. The median of the national coverage rates for DTP1 increased from 57% in children aged 12 weeks to 88% at 12 months, and for DTP3 from 65% at 12 months to 76% at three years.

The authors conclude: "The timeliness of children's vaccination varies widely between and particularly within countries, and published yearly estimates of national coverage do not capture these variations. Delayed vaccination could have important implications for the effect of new and established vaccines on the burden of disease."

In an accompanying Comment, Dr Jim Buttery Monash University, Monash Medical Centre, Melbourne and Royal Children's Hospital, Melbourne, Australia, and Dr Stephen Graham, University of Melbourne and Royal Children's Hospital, Melbourne, Australia, say: "There is some cause for optimism. Countries as diverse as Rwanda, Egypt, and Peru provide high coverage with timely administration. Many countries use opportunistic immunisation to minimise missed opportunities. Potentially generalisable lessons can be learnt from these successes."

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Dr Colin Sanderson, London School of Hygiene and Tropical Medicine, UK T) +44 (0)207 927 2231 E) colin.sanderson@lshtm.ac.uk

Dr Jim Buttery, Monash University, Monash Medical Centre, Melbourne, and Royal Children's Hospital, Melbourne, Australia T) +61 3 9345 5522 E) jim.buttery@mcri.edu.au

For full Article and Comment: http://press.thelancet.com/vaccinations45.pdf

Notes to editors:

*45 countries: Bangladesh, Benin, Bolivia, Brazil, Burkina Faso, Cambodia, Cameroon, Chad, Colombia, Comoros, Congo, Dominican Republic, Ivory Coast, Egypt, Eritrea, Gabon, Ghana, Guatemala, Guinea, Haiti, Honduras, India, Kenya, Kyrgyz, Lesotho, Madagascar, Malawi, Mali, Mauritania, Morocco, Mozambique, Namibia, Nicaragua, Niger, Nigeria, Peru, Rwanda, Senegal, Tanzania, Togo, Turkey, Uganda, Uzbekistan, Yemen, Zambia


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