Will the New Vaccine Help Eradicate Malaria?
The malaria vaccine may well help reduce deaths, but we should not exaggerate its efficacy.
On 22 January 2024, Cameroon was the first nation in the world to roll out a routine vaccine for malaria. This age-old scourge still kills over 1,600 children in Africa every day, and, until now, a vaccine has never been available. Vaccines are among the most effective public health measures to combat everything from smallpox to COVID. However, they can be oversold. So, how does this malaria vaccine stack up?
In its most recent report on malaria, the World Health Organization stated that in 2021 there were 247 million cases in 84 countries in which the disease is endemic. The good news is that, although the number of cases remains high, deaths from malaria fell from nearly 900,000 in 2000 to around 570,000 in 2019. Much of that reduction was due to the use of insecticides—in both spray form and impregnated into bed nets—which prevent mosquitoes from infecting people with the parasite that causes the disease. Unfortunately, however, deaths rose to around 620,000 in 2020 and 2021 “due to disruptions to essential malaria services during the COVID-19 pandemic.”
Tragically, children are especially vulnerable to malaria. Thankfully, most survive the disease, but their schooling is generally severely disrupted and caring for them places an enormous burden on families, especially mothers.
Malaria is often thought of as a purely tropical disease, but this is incorrect. It used to ravage much of Europe. It was even endemic in temperate Britain: Oliver Cromwell died of malaria on a wet and windy September day of 1658. Shakespeare mentions it, as the “ague,” in several plays. In The Tempest, the slave Caliban hopes that his despised master Prospero will be struck down by the disease. Malaria remained endemic in Southern Europe and the US until the second half of the 20th century. Economic development was key to its eradication. Greater prosperity led to improvements in housing, including proper windows that shut out mosquitoes; better diets; increased access to diagnosis and treatments; and the large-scale use of insecticides to wipe out mosquito breeding sites.
Paul A. Offit
Many tropical countries—including Malaysia, Singapore, Sri Lanka, Colombia, and the Philippines—have largely or completely eradicated the disease. But for poorer countries, public health interventions remain vital, and vaccines can play an important part in this.
Cameroon, a nation of 27 million, had 6.6 million malaria cases in 2021, of which at least 3,782 were fatal. Cameroon could certainly use a malaria vaccine. And so the rollout began in early January in the 42 districts with the highest rates of morbidity and mortality. Children around the age of six months will each receive four doses over 18 months.
Parasites such as the ones that cause malaria are notoriously difficult to vaccinate against due to the lifecycle of the disease. The vaccine being rolled out in Cameroon is, at best, 36 percent effective, if correctly administered. During phase 3 clinical trials, the vaccine proved far less effective when given to infants younger than six months. Since timing is so important, the administration of the doses will require significant logistical support. We don’t know how effective the vaccine will be if even one dose is missed or mistimed.
Since powerful interests—from the Gates Foundation and Gavi, the Vaccine Alliance, to the WHO, the World Bank, and UNICEF—are backing the vaccine, the logistical support should be available. But supply is a trickier issue. At the moment, only 18 million doses of the vaccine are likely to be available by the end of 2025 for the twenty or so countries that want to participate in the trials. Production will need to be ramped up. Efficacy will fall well below 36 percent if doses are missed because resources have been spread too thin.
The BBC reports that a newer vaccine developed by Oxford University with up to 70 percent efficacy could be rolled out soon. The Serum Institute of India could be producing 100 million doses within the next year. So, the future for malaria vaccines looks bright, even if the rollout may take some time.
I asked Professor Donald Roberts, one of the world’s leading experts on malaria, what he thought about these new vaccines. Roberts has been working on malaria since first undertaking field research with the Walter Reed Army Institute of Research in the 1960s. Roberts commented, “When the vaccine is free [and] does not entail reductions in bed net distribution or indoor residual spray programs, then the program is additive. As such, malaria vaccine distribution should help reduce infant malaria mortality.” Note the caveats.
As we learned during COVID, people react to incentives and will change their behaviour if they think they’re already protected from a disease. Will the vaccinated continue to sleep under bed nets when it is swelteringly hot and humid? If not, then malaria transmission may increase. Will parents continue to presumptively treat their children’s fevers as malaria? It’s often easier to buy malaria medicines for your child than to get them tested for the disease. However, such medicines are relatively expensive compared with simple fever suppressants such as acetaminophen (paracetamol), so parents may not treat a vaccinated child with fever for malaria. If that child does have malaria, they may suffer permanent brain damage or die. Also, will we see any unpleasant side effects (real or perceived) from the vaccine that haven’t been reported in clinical trials? As we saw with myocarditis resulting from COVID vaccines, if side effects are rare, they do not necessarily negate the case for vaccinating healthy children, but they might prompt public resistance to the vaccine. (Vaccine sceptics should be treated with respect.)
Mark Halloran
While none of these concerns should lead us to oppose a vaccination campaign, they do suggest that we should be careful not to make unrealistic promises.
The US government has helped to combat malaria overseas since at least the Second World War. During the 1950s and 60s, massive campaigns involving insecticide spraying helped lower the incidence of malaria across the board and contributed to the eradication of the disease from many nations in the Middle East, Southern Europe, and Latin America. In the 1980s, spraying and bed net programs had some effect in Africa, where most malaria deaths occur. But poverty and weak health systems stymied such efforts. The US programs in the early part of this century were largely ineffective but finally took off with the launch of the US President’s Malaria Initiative in 2005. Americans can be proud that their government has helped alleviate much suffering from this disease, especially over the past two decades.
There are at least two reasons for US taxpayers to fund widespread rollouts of malaria vaccines in foreign countries. First, we can afford it, and it is the right thing to do. Second, it promotes America’s image abroad through so-called “vaccine diplomacy” and wins hearts and minds in developing nations that may become future trade partners.
Political leaders like French president Emmanuel Macron advocated “vaccine diplomacy” during the COVID pandemic. Likewise, several academics and policy wonks have been advocating “vaccine diplomacy” for malaria. Paul Wolfowitz, former World Bank boss and Deputy Defence Secretary during the George W. Bush administration, explained to me several years ago that this approach would help draw African nations into our orbit and away from China and Russia. He maintained that it was arguments like these that encouraged policy hawks to support the massive US government health initiatives (especially to combat HIV, TB, and malaria in Africa) established during the Bush administration and continued and expanded by later administrations.
After all, vaccine distribution is relatively cheap compared to other large-scale political interventions—and vastly cheaper than military support.
But we need to be careful how we do this and, in particular, we should learn from the mistakes made during the COVID vaccine campaign. Some public health officials who played leading roles during the recent pandemic—notably, Francis Collins and Anthony Fauci—now acknowledge that vaccine hesitancy is increasing, but they refuse to admit that this is because much of their advice was incorrect, even if it was based upon the best information available at the time (which itself can be disputed). The COVID vaccine was not 95 percent effective; it did not prevent transmission; and naturally acquired immunity from having had the disease was not inferior to that produced by the vaccine. The risks of not being transparent about such things are significant.
We see the dangers of not being open with the public in Europe, where vaccine hesitancy is rapidly rising and we are seeing a resurgence of some terrible diseases: there has been a 45-fold increase in measles across Europe, for example.
The fallout from the pandemic and from our response to it will be with us for a long time. And it should inform the current efforts to combat malaria. The malaria vaccine may well help reduce deaths, but we should not exaggerate its efficacy. Until a more effective, longer-lasting, single-dose vaccine that is easy to administer and store is rolled out, the vaccine will be just another weapon in the arsenal, not the solution. So, let’s manage people’s expectations. We should explain to the parents of African children, the African governments who will have to help with rollout, the American taxpayers who will fund this, and the agencies who will be in charge that the new malaria vaccine will be a partial solution at best. Then maybe the vaccine’s impact will exceed expectations.
