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There were 386,000 malaria deaths in sub-Saharan Africa in 2018, and projections suggest that the COVID-19 pandemic could cause that number to double – to 769,000 deaths – owing  to a lack of access to malaria prevention and treatment tools. This is a worst-case scenario, but there is no doubt that the development of a more effective,  safe, commercially available vaccine for malaria would be a game changer.  

Trials for one vaccine candidate, RTS,S, began a year ago, and the figures above underline how sorely a vaccine continues to be needed. Whether it is RTS,S or another vaccine candidate, it would become a crucial part of the existing arsenal of preventive, diagnostic and treatment tools used to combat malaria, including the use of long lasting insecticidal nets, indoor residual spraying, chemoprevention treatments and effective case management.  

Following extensive clinical trials, in 2015, WHO recommended a pilot programme for RTS,S take place in Ghana, Kenya and Malawi with the aim of vaccinating 360,000 children each year until 2023. With support from the Ministries of Health in each country and international donors including GlaxoSmithKline and the Global Fund, the trial has reached thousands of children and the very early signs are positive.  

But is a malaria vaccine the ‘silver bullet’ some believe it to be? Discovering a viable vaccine would be a huge step forward – but what other challenges lie in wait? 

 Hard to reach, hard to vaccinate

Populations that are most affected by malaria often sit in one of two categories: hard to reach and hard to vaccinate. Some people sit in both.  

This definition is important because it clearly illustrates the challenges of rolling out vaccines to those in need once they are produced. Malaria Consortium believes these challenges are considerable but not insurmountable. 

Defining hard to reach or hard to vaccinate

Hard-to-reach populations are those who face supply-side barriers to vaccination due to geography by distance or terrain, transient or nomadic movement, healthcare provider discrimination, lack of healthcare provider recommendations, inadequate vaccination systems, war and conflict, home births or other home-bound mobility limitations or legal restrictions.

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Hard-to-vaccinate populations are those who are reachable but difficult to vaccinate because of demand-side barriers such as distrust, religious beliefs, lack of awareness, poverty or low socio-economic status, lack of time, or gender-based discrimination.

Ozawa et al (2019)

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There are significant supply-side barriers involved in trying to deliver health care to hard-to-reach populations. Malaria Consortium’s seasonal malaria chemoprevention (SMC) programme aimed to reach more than six million children across the Sahel region of Africa in 2019 with life-saving anti-malaria drugs. Like any prospective vaccine distribution, the SMC programme had to overcome vast geographic challenges, varying levels of health infrastructure as well as security issues related to ongoing conflict. These issues have been overcome and the programme is successful largely due to strong partnerships between the programme team and national and regional governments, donors and other organisations operating in the same areas. 

Future vaccine distributions should learn from the experience of previous mass drug distributions like this and, where possible, consider co-delivery of vaccines with other core interventions like SMC in order to reach as many people as possible. Further studies will likely be required to determine the operational feasibility of rolling out either the RTS,S vaccine or an alternative at scale. These studies will also need to take into account transient populations, and how we can ensure that they receive the vaccine.  

Demand-side barriers  

Even if these considerable supply-side barriers are overcome, demand-side barriers are sometimes even more delicate to navigate. These barriers can include the spread of mistrust and misinformation, prohibitive social or religious norms, low levels of awareness and low socio-economic status – all of which can lead to low uptake of vaccinations. These barriers render some populations ‘hard-to-vaccinate’.  

Objections to immunisation for cultural or religious reasons is common around the world. At Malaria Consortium, we have experienced similar problems with uptake of malaria in pregnancy services, when these cultural norms often limit or prevent attendance at antenatal clinics.  

In Uganda, Malaria Consortium’s work on social and behaviour change in rural communities is helping to increase the uptake of maternal services by raising awareness and dispelling myths around the use of medicines. Similar activities will have to be undertaken to aid the acceptability of any future malaria vaccine among hard-to-vaccinate communities.  

Further studies are needed 

Hard-to-reach and hard-to-vaccinate populations will provide key challenges to the effective delivery of a malaria vaccine when it has been developed, and further studies are needed in this area. Whether it is the RTS,S vaccine currently in trials, or one of the more than 20 other malaria vaccine candidates, it is clear that a successful vaccine alone will not bring down the number of malaria deaths each year. A delivery strategy that takes into account these supply-side and demand-side barriers is crucial if we want to reach the world’s most vulnerable people.  

Learn more about Malaria Consortium’s position on vaccines in our new Future Health position statement on the topic. 

Ashley Giles is Senior Communications Officer at Malaria Consortium.

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