There are seven global health days specified by the WHO dedicated to raising awareness of specific global health issues. However, one issue has been dedicated a whole week. Immunisation.

As I see it, there couldn’t be a better occasion for me to publish my first blog for the new RESULTS UK website than World Immunisation Week.

Immunisation is one of RESULTS UK’s core issues as part of our goal of improving global health, especially for the poorest and most marginalised individuals, families, and communities in developing countries. We believe every child deserves the chance to live beyond their fifth birthday. Immunisation, which protects against preventable illnesses and stop unnecessary deaths, is one of the most important health interventions available.

But why do we think that?

Here are five reasons why immunisation is one of the most important health interventions there is.

1. Immunisation saves lives

It is estimated 2-3 million lives are saved every year by immunisation. Immunisation contributed significantly to the halving of under-5 mortality rates between 1990 – 2015; progress largely driven by the Millennium Development Goals.

Currently, 18.7 million children miss out on basic vaccines. I think this is unacceptable and puts 18.7 million too many children at risk of harmful infectious diseases because a simple, cost effective vaccine was not available to them.

2. Value for money

For every $1 spent on immunisation, $16 is returned. Immunisation is one of the most cost effective health interventions. Some life-saving vaccines cost just pennies, require only one dose, and provide immunisation throughout life.

3. Global Health Security

Immunisation programmes play an important role in the prevention of epidemics: not just through immunisation of a specific disease but by way of the wider impact routine immunisation has on the health system. It strengthens the ability to react to health emergencies. As one example, Nigeria was able to limit the number of deaths from Ebola to just seven because they were able to quickly use their knowledge and systems designed to control and prevent polio to react to an emerging threat. This prevented Nigeria facing an epidemic and experiencing the same catastrophic destruction of its health system, which often leads to future health problem, as was seen  in Sierra Leone and Liberia.

4. Routine immunisation strengthens health systems

Children who miss out on immunisation are also more likely to miss out on all health interventions. Routine immunisation is often a baseline service of a primary health care system and helps ensure services reach the poorest and most marginalised in societies. The infrastructure required to reach every child with immunisation allows health workers and medicines to reach communities with other health services, consequently increasing equitable access to a greater number of services.

5. Drives equity

The principle of equity is at the heart of immunisation programmes. Reaching every child with a vaccine is essential to control and eradicate diseases. Polio is a prime example of this. High immunisation rates are essential to prevent the disease making a resurgence and are a key factor in its near elimination. Millions of health workers and volunteers have focused on reaching every last child; in many places even those children who usually miss out, were reached.

Throughout World Immunisation Week we’ll be sharing new publications, infographics and blogs to raise awareness of the inequities and challenges we need to address if we are to reach universal immunisation coverage. Follow us, and get involved, on Twitter and Facebook.