I’ve spent the past two weeks preparing a Grand Rounds presentation on “Chiropractic and the Pediatric Patient” for my hospital and pediatricians in the community. I gave the talk on Wednesday and I believe it went well. For fun, I had time at the end for a bit of lagniappe so I showed videos of applied kinesiology surrogate testing, KST tandem adjustments, and the “Ring Dinger“.
So, a short post today. But it’s a post about a huge achievement in pediatric medicine that will save thousands of lives every year around the world. There is now have a safe, effective, and WHO-endorsed malaria vaccine for broad use in children living in regions where malaria is prevalent.
I really can’t stress enough how important this is. Malaria, a mosquito-borne disease caused by infection with a member of the unicellular Plasmodium parasite group, is one of the deadliest infectious diseases that humans have had to face. Over time, with mosquito control efforts involving insecticides, improved water drainage, and physical barriers, the surface area of the Earth where malaria is a concern has decreased dramatically. Still, 40% of the world’s population is at risk, particularly those living in poor tropical and sub-tropical regions, with sub-Saharan Africa taking the brunt of morbidity and mortality associated with the disease. There are still about 1,500-2,000 cases diagnosed in the United States every year in travelers.
The number of people that develop malaria every year is staggering. In 2019, there were 229 million clinical cases and 409,000 deaths. Most of these deaths occurred in children living in sub-Saharan Africa and these totals are almost certainly a significant undercount of the true prevalence and mortality.
More than 200,000 of those deaths involved children under the age of 5 years. Young children are often infected repeatedly during this period, with each infection potentially being fatal. Those who survive might develop partial immunity to malaria, which is why severe disease is less likely in adults. As with COVID-19 in children, death is not the only outcome of concern. Repeated bouts of malaria can leave a child malnourished, weak, and vulnerable to other infections. Obviously, the goal of any vaccine would be to provide some degree of protection without the risk of death from severe anemia, organ failure, or stroke.
The RTS,S/AS01 vaccine, now named Mosquirix, is the first vaccine against a parasitic organism and targets the member of the Plasmodium group that is most associated with severe and life-threatening illness. It works by limiting the ability of P. falciparum to gain access to the liver, where it typically would mature and multiply before moving on to invade it’s victim’s red blood cells. The vaccine results in immunity against the circumsporozoite protein that is found on the surface of the malaria parasite when in the form that initially enters the body via the bite of an infected mosquito.
Here is the official statement from WHO:
WHO recommends that in the context of comprehensive malaria control the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum malaria in children living in regions with moderate to high transmission as defined by WHO. RTS,S/AS01 malaria vaccine should be provided in a schedule of 4 doses in children from 5 months of age for the reduction of malaria disease and burden.
They feel that the vaccine is feasible to delivery and will improve equity of malaria prevention strategies, being able to reach children who may not have access to things like insecticide-coated bednets or modernized drainage systems to reduce standing water and mosquito populations. The vaccine looks to be safe as well, with no major concerns seen during studies involving 2.3 million doses in 3 African countries. The safety profile isn’t spotless, however. There was an issue of a small increased risk of meningitis, though not at all the involved sites. Researchers felt that it was likely a fluke. Pilot studies are still underway, so this potential problem remains a focus. The vaccine is also highly cost-effective in regions with lots of malaria.
When it comes to the effectiveness of the vaccine, it is good but certainly could be better. Still, a moderately effective vaccine that prevents 40% of total cases and a third of severe cases in the most vulnerable population is amazing. WHO predicts that RTS,S/AS01 vaccine, which has been in development since the 1980s, will prevent 5 million cases and 23,000 deaths every year. It’s a first step, however, with other vaccines in the works that look even more promising. The ultimate goal of WHO is a vaccine that is 75% effective.