4.1 Vaccination revisited
In principle, a vaccination is a relatively simple event, because it does not require any changes to social structures or long-term personal behaviour, both of which may be difficult to achieve or sustain. The success of vaccination programmes is not dependent on radical changes in society; it depends on the organisation, funding and delivery of vaccines to populations in need of protection from vaccine-preventable diseases (VPDs).
By comparison with other public health interventions that could have an equal or greater impact, such as the universal provision of clean water and sanitation, vaccination is a relatively cheap disease prevention and health promotion strategy. It has achieved some notable successes, a number of which are briefly summarised here.
When the WHO initiated the Expanded Programme on Immunization (EPI) in 1974, fewer than 5% of the world’s infants were fully immunised during the first year of life against the six main VPDs:
In order to track progress towards increasing vaccine coverage, WHO member states agreed to use the proportion of infants (i.e. those under one year) receiving all three scheduled doses of the combined vaccine against diphtheria, tetanus and pertussis (known as ‘DTP3 coverage’, or sometimes ‘DPT3 coverage’) as the main indicator of immunisation programme performance. By 2010, DTP3 coverage in WHO member states was protecting 85% of infants against these three diseases, with a target to reach 90% by 2015 (WHO, 2012g).
Coverage with measles-containing vaccines has also increased worldwide to 83% globally among children aged 12–23 months. This campaign has achieved a reduction from 4 million cases of measles and 2.6 million child deaths in 1980, to fewer than 118 000 cases contributing 1% of deaths in children under five in 2008 (WHO, 2012h).
Polio, measles and neonatal tetanus are the VPDs at the top of the WHO’s target list for global eradication, following the successful campaign to rid the world of smallpox.