IMVACS

The challenge

Although preventive measures have had a major impact, in malaria-endemic countries, the disease is so common that it continues to be a huge public health challenge, as more than 250 million cases occur each year in sub-Saharan Africa.

In areas where malaria is seasonal (most cases occurring during a particular period of the year), the WHO recommends seasonal malaria chemoprevention (SMC) – multiple rounds of pre-emptive antimalarial drug use – to protect young children against infection. More recently, two malaria vaccines – RTS,S/AS01 and R21/Matrix-M – have been shown to offer good levels of protection and are recommended for use alongside other control measures, such as insecticide-impregnated bed nets.

However, the malaria vaccine schedule is complex, involving a three-dose primary schedule in the first year of life and a fourth dose in year 2. As with most vaccines, it is recommended that doses be given at specific ages to optimise protection. Where malaria is highly seasonal, however, the age-based approach may be less effective than one in which a fourth booster dose is given directly before the malaria season, so that children are maximally protected when the risk of malaria is highest. Modelling suggests that seasonal vaccination would likely prevent more infections. 

In addition, there is generally a high take-up of seasonal malaria chemoprevention. Integrating malaria vaccination with SMC campaigns might therefore improve vaccine coverage, which tends to be lower for later doses. While combining the two programmes would require careful operational coordination, it also offers an opportunity to build on existing delivery systems and strengthen real-world impact.

The project

The IMVACS project is testing the hypothesis that integrating malaria vaccination with seasonal malaria chemoprevention (SMC) might provide better overall protection, and is exploring the acceptability, feasibility, and cost-effectiveness of the integrated approach.

The project is conducting a trial in Burkina Faso and Mali, in areas where malaria transmission is highly seasonal and represents a major public health concern.  The trial will compare the community-level malaria burden under two different vaccine delivery strategies: 

• Age-based delivery for both the three-dose primary series and the booster dose, all provided through the national immunisation programme.
• Delivery of the primary vaccine series during successive SMC rounds, with the booster dose administered during the following year’s SMC campaign.

The project team is working with a broad range of stakeholders to optimise the integrated delivery strategy in both countries. It is collecting data on malaria cases treated in health facilities, surveying communities at the end of the malaria season to assess infection rates, and tracking vaccine coverage achieved. Consultations with caregivers and health workers will provide insights into the acceptability and feasibility of the integrated approach. A cost-effectiveness analysis will also be carried out.

Impact

The IMVACS project will provide health managers with highly policy-relevant evidence on malaria prevention. It will:

• Show whether integration of malaria vaccination with seasonal malaria chemoprevention (SMC) leads to higher vaccine coverage and reduces the community burden of malaria.
• Reveal whether an integrated approach is practical to implement and acceptable to caregivers.
• Demonstrate whether the benefits justify any additional costs. 

With malaria still requiring a multifaceted approach to prevention, the IMVACS project will show whether integration of SMC and vaccination further reduces the burden of malaria, thereby preventing even more childhood deaths and cases of serious disease.