"Close the Immunisation Gap" is the theme for World Immunisation Week marked from 24 to 30 April. Despite the availability of effective vaccines, 1.5 million children from across the world, including South Africa, die each year from preventable diseases.

Three in every 10 South African children do not receive all their vaccinations, leaving them vulnerable to deadly diseases that could easily have been prevented.

"Immunisation is one of the most successful and cost-effective means to save children's lives and help them grow into healthy adults," says Prof Charles Wiysonge, deputy director of the Centre for Evidence-based Health Care at Stellenbosch University's Faculty of Medicine and Health Sciences (FMHS).

"Immunisation is important in all stages of an individual's life as it helps children and adolescents fight infectious diseases and restores waning immunity in adults. In addition to benefits to the individual who receives the vaccine, immunisation helps protect his or her family members, friends, and the community at large," Wiysonge says.

Worldwide immunisation is estimated to prevent more than three million deaths each year that would have been caused by measles, pertussis, tetanus, diphtheria, pneumonia and diarrhoea.

"One in four children in Africa is still not receiving the vaccinations he or she needs," says Wiysonge, who serves on the World Health Organisation's (WHO) Strategic Advisory Group of Experts on Immunisation as well as the African Task Force on Immunisation. "Only 70% of children in South Africa receive all their vaccinations – this is less than the average for the whole of sub-Saharan Africa, which is estimated at 77% by the WHO and the United Nations Children's Emergency Fund (UNICEF)."

There are several reasons why children don't receive all their vaccinations. "In general, the child who doesn't have access to immunisation in Africa is likely to be marginalised, living in poorly-served rural or remote areas, or deprived urban settings. In addition, a new phenomenon is emerging in well-served urban settings in South Africa known as vaccine hesitancy, where people may accept all vaccines or only some vaccines, but are hesitant to take them up, or may totally reject all vaccines." says Wiysonge.

"It is within our power to close this immunisation gap. Increased political and financial commitments are required from African governments to maintain the current achievements and make progress. Parents, guardians, adolescents, adults, and health workers also need to understand the vital importance of keeping immunisations up to date," says Wiysonge.

VACCINE PREVENTABLE DEATHS

1.5 million children die each year from diseases that can be prevented by vaccines. These include:

• 476 000 deaths from pneumococcal disease
• 453 000 deaths from rotavirus diarrhoea
• 199 000 deaths from Haemophilus influenzae type b
• 195 000 deaths from pertussis
• 118 000 deaths from measles
• 59 000 deaths from neonatal tetanus

VACCINE SUCCESS STORY

Measles used to kill millions of children, and in some parts of Africa people were used to saying that one can never count his or her children until measles has come and gone. However, accelerated immunisation activities have had a major impact on reducing measles deaths. It is estimated that in 2000 more than 500 000 children under five years of age died from measles worldwide, but in 2015 the number of child deaths caused by measles had reduced to about 100 000, i.e. an 80% reduction in child deaths. It is estimated that measles vaccination prevented more than 17 million deaths between 2000 and 2014.

Photo: Prof Charles Wiysonge