Just over 90% of the world’s infants – 123 million of them – received at least one vaccination in 2016, according to figures released by the US Centres for Disease Control and Prevention (CDC).
The global use of many other types of vaccine increased during the same period, although several, including those used to protect against rotavirus, pneumococcal disease, and rubella, remained below 50% of eligible people. Influenza and hepatitis B vaccinations both increased, hitting 70% and 84% coverage respectively.
In a paper published by the CDC, a team of epidemiologists led by the organisation’s own Leora Feldstein looked first at the number of children around the world who completed the three-dose combined vax for diphtheria, tetanus and pertussis (whooping cough), known as DTP.
The team found the situation unchanged since 2010, with between 84 and 86% of kids completing the course. The World Health Organisation’s Global Vaccine Action Plan calls for a completing rate of 90% or better.
The drop-out rate – the measure of children who received at least one but not all three doses – was 5%, globally averaged, but that figure masks some huge discrepancies. In the Western Pacific Region, the rate was just 0.4%, but in Africa it hit a worrying 11%.
Indeed, out of seven countries that recorded a DTP vax rate of less than 50%, five are in Africa. They are the Central African Republic, Equatorial Guinea, Nigeria, Somalia and South Sudan. They are joined at the bottom of the league by Ukraine and Syria.
“Nearly all are in conflict or facing serious economic turmoil,” the researchers write. “Consequently, maintaining coverage with existing vaccines and introducing new vaccines in these countries is particularly challenging.”
The CDC report calls for greater efforts to increase vaccination rates, particularly in Africa, the eastern Mediterranean and south-east Asia. Across these three regions in 2016, they report, some 11 million infants did not receive even the first DTP vax dose, and 18 million did not receive the first of the two-part vaccination for meningococcal C.
Feldstein and her colleagues call for widespread changes to vaccination roll-outs on a country by country basis. They note that hurdles include logistic problems, such as insufficient stocks; geographic issues, such as accessing remote communities; and organisational barriers, such as lack of political will.
Strategies to include challenging communities, they note, will be different to those aimed at reducing the drop-out rate.
“Improving both initiation of vaccination and completion of the series is essential for establishing sustainable national immunisation programs and to eliminating preventable diseases and deaths among children,” they conclude.
Andrew Masterson is a former editor of Cosmos.
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