Source: The Guardian
Mosquirix is one of the most widely anticipated vaccines to have been developed. It is the first vaccine for malaria – a disease that kills more than 1,200 childrenevery day– and has been clinically proven to provide protection against the disease. So, given that it has passed the toughest regulatory hurdles required of it, why is it only being made available in a handful of countries?
Demand for the vaccine is likely to be high. With more than 200m cases a year, malaria is endemic in almost every country in sub-Saharan Africa, as well as large parts of Asia and Latin America. Last week, two advisory bodies to the World Health Organisation, the strategic advisory group of experts on immunisation and the malaria policy advisory committee, recommended against its immediate widespread use, and many people may have been left wondering why.
But it was a smart call. While there is a potential to save many lives with this vaccine, we have reason to tread carefully. Rather than being a simple solution, Mosquirix comes with complex caveats and some outstanding questions that the clinical studies were not able to address. While some may argue that any delay in getting the vaccine out to people could end up costing lives, experts first want certainty that, in a real-life setting, it indeed brings the benefits we expect, based on what was shown in the trials.
Clinical trials found Mosquirix to be both safe and effective, providing 39% efficacy at preventing clinical cases of malaria over the course of a four-year trial. While this is low for a vaccine, it is worth remembering that given the large number of people at risk, providing protection in just four out of 10 cases could still go a very long way. Moreover, since there can be more than one episode per child, the trials found that the vaccine prevented on average 1,774 cases of malaria per 1,000 children.
However, what happens during the controlled setting of a clinical trial does not necessarily translate into a real-world situation, and here lies the concern.
To begin with, Mosquirix requires four doses. That’s a lot for a vaccine. What’s more, trials suggest that its already low efficacy is further reduced if the fourth dose is not administered, down to about 28% protection against clinical malaria and reducing its impact on severe cases of malaria to nearly zero. That is worrying because, typically, the more doses required of a vaccine the higher the dropout rate.
Categories: Health