This is a guest post from the Bill and Melinda Gates Foundation, originally published on their Impatient Optimists blog.

Dr. K.O. Antwi-Agyei manages the Expanded Programme on Immunisation in Ghana, where he oversees the day-to-day work to ensure vaccines reach children across the country.

Ghana’s health care system has put a lot of its resources into vaccines. Why?

We can see a lot of achievements in reducing child deaths by investing in delivering vaccines. The returns are high, so the politicians and policy makers are convinced that it’s worth investing in vaccines. That is why at least every year within our budget we ensure that we pay for all our traditional vaccines.

Our communities have also been great because they embrace vaccination. They even testify that “Oh, our children used to die from measles. Now with vaccination, we don’t see measles.” And of course, they allow our staff into their homes. There is trust. We can now return to the communities with other vaccination campaigns. It’s marvelous.

What impact have vaccines had on the health of Ghana’s population?

Around 1974, immunisation coverage was around 1.6 percent. Today, well over 90 percent of our population is covered by immunisation services, reducing the burden of disease.

For example, measles used to be the number two killer of children. Now it’s no longer a cause of death for the past 10 years in Ghana. So a lot has been achieved through immunisations.

Last year, you were the first immunisation chief in Africa to simultaneously roll out two vaccines, one protecting children against pneumonia and the other against rotavirus. Why did you decide to do that and, and what was the result?

Our desire to reach the Millennium Development Goal to reduce childhood death was a very big motivating factor. Apart from malaria, pneumonia and diarrhea are the two highest killing diseases. So we thought, if there is no vaccine against malaria now, and there are vaccines against pneumonia and diarrhea, then it’s worth fighting. So we decided to fight the two together. We thought it would be difficult, but not an impossibility. And with careful planning, we could succeed.

How important are Ghana’s community health workers in delivering the vaccines?

They are very important. The front line health workers, they are in touch with the communities. They help improve our public health services, not only through vaccinations but also by treating minor illnesses offering family planning and providing other health-related services.

How does Ghana use data collection to improve immunisation coverage?

Data is used for making decisions. If your data is not good, then of course your decisions will also be faulty, and you won’t be able to achieve your objectives. So a lot of effort has gone into data reporting. We developed tally and register books for the basic level so that they are able to pick the necessary data on children vaccinated, and also on what vaccines have been used. We firmly believe that if you won’t use the data, then don’t collect it. So once we collect the data, we use it. If a region’s coverage is low, we immediately ask, “What is happening there?” We go and investigate and then give us feedback. Then, whatever the error is, we discuss it and correct it.

What is your long term goal for Ghana’s immunisation program?

To reach the top is difficult, but to remain at the top is even more difficult. For Ghana, our goal is to remain as a leader in the area of immunisation and to show our commitment and to develop initiatives which can spread to other areas. Whatever is happening in other countries has a bearing on us. We want to have success stories which can be shared so that together we can get rid of diseases which are killing our children and mothers.

This week is World Immunisation Week. Find out more about how ONE is supporting access to vaccinations.