A milestone for global health, 3 decades in development

 Joe Cohen is co-inventor of the RTS,S vaccine, the world’s first malaria vaccine to be introduced in a pilot programme. Formerly a research scientist with the pharmaceutical company GSK, Joe Cohen has been involved in the development of this landmark vaccine since its conceptualization. He shares his thoughts on what this moment means for global health.

How did the RTS,S malaria vaccine come to be?

It’s a very, very long story that started more than 30 years ago. The short version is that there are 3 main factors that have contributed to making this vaccine what it is today.

First is the science, and the scientists who worked on this vaccine at all the stages of its development, from the start, from the concept, to the various components that were added to the vaccine as it was developed. And the science that went into making the actual vaccine – producing it, manufacturing it, and its clinical testing.

Another very important factor was the fantastic partnership that came together to develop this vaccine: GSK, the Malaria Vaccine Initiative at PATH, the Walter Reed Army Institute of Research and, most importantly, all the African scientists that contributed in many African countries.

The last thing that I want to say is “hats off” to GSK senior management that has always been supportive of the work on this vaccine.

What was your own role in developing the vaccine?

I was very fortunate to be involved in the very early stages of developing the RTS,S vaccine and in its initial concept. Actually I’m a co-inventor on the first and main patent that was obtained on the RTS,S vaccine.

I was very fortunate that I was able to be involved and lead the team throughout the development of the vaccine until it reached phase III clinical trials in Africa, and until I eventually retired. It was my good luck that I could follow every step of this vaccine from the very early stages to the final stages of the clinical trials.

What are the critical components of the vaccine?

There are several pieces of information that came together to make this concept work.

First is the choice of protein - the so-called antigen that we selected for the vaccine. It’s the CSP (circumsporozoite) protein which is an important part of the vaccine.

The second important part is the way this protein was presented in the form of a virus-like particle.

And finally, the last very important part is the adjuvant system that really is indispensable for the vaccine to produce an effective immune response.

These 3 important ideas came together in the initial concept – the antigen, the way it is presented in the form of particles and the addition of an adjuvant system to improve immune response.

Why was the vaccine so long in the making?

We have many vaccines against viruses, and we have vaccines against bacteria. However, until now, we didn’t have any vaccine against a parasite. The major difficulty is that parasites are extremely complex organisms with complex genome structures. They are very well adapted to escaping the defense responses of the human body by several mechanisms, including changing and evolving their appearance.

I’m sure that the lessons learned from the science point of view will be useful in applying to development of other vaccines.

The extensive private-public partnership which was created to lead the development of the vaccine was the first and one of its kind. It required extensive discussions and eventual consensus among the numerous partners involved.

What do you anticipate being the impact of the vaccine where it will be introduced?

We know from our Phase III trial results that this vaccine can have very important public health impact. This vaccine is not perfect but we know that it can, if it’s introduced broadly, potentially help save hundreds and thousands of lives.

All indications are that if this vaccine is implementable on a large scale, it will have tremendous public health effects. That is really what we have worked for, not just me, but the hundreds and hundreds of people involved, who have worked on it for these 30-odd years.

What does the current vaccine introduction in Africa mean to you?

This morning when I received the first picture of the RTS,S vaccine introduction, I was really, really surprised. Of course, I know how important this moment is, but still I was surprised by my reaction when I saw this picture.

After all, it’s just a picture of a kid being vaccinated, but this particular one literally gave me an adrenaline rush. I felt like my heartbeat increased for a few seconds or so.

I think it reflects how momentous this first vaccination is and what it means for children in Africa, and also what it means to me personally as someone who has been involved in this project.

It’s a tremendous achievement and a very important moment in the fight against malaria.

After 30 years in development, Malawi became the first country to introduce the RTS,S malaria vaccine on 23 April 2019 as part of a new pilot programme in Africa. Ghana introduced the vaccine on 30 April, and Kenya is expected to follow in the coming weeks.

Led by the Ministries in Health in Ghana, Kenya and Malawi, the pilot is being funded by Gavi, the Vaccine Alliance; the Global Fund to Fight AIDS, Tuberculosis and Malaria, and Unitaid. WHO, PATH and GSK are providing additional contributions, with GSK donating up to 10 million doses of the vaccine for the pilot.