Topline
While researchers have spent decades searching for malaria vaccines, only two have ever been authorized, a situation many scientists hope to change as they race to leverage new technology against one of humanity’s oldest and deadliest foes—including a breakthrough mRNA vaccine unveiled by researchers this week.
There are now two malaria vaccines authorized for use against the ancient scourge.
Key Facts
GSK’s malaria vaccine—RTS,S or Mosquirix—was celebrated as a major public health milestone in 2021 when it became the first ever shot to get the green light for widespread use in children from the World Health Organization. The vaccine was the product of a decades-long partnership between private and public organizations like GSK, the Wellcome Trust and the Bill and Melinda Gates Foundation.
Outlook: Though certainly a breakthrough, the GSK shot has been slow to roll out and clinical trial data indicates a large margin for improvement, with the shot only 30% effective at preventing severe malaria in children.
The University of Oxford unveiled a “game-changer” vaccine in 2022 that researchers say is better and cheaper than GSK’s shot and already has deals in place to ramp up production to more than 100 million doses a year, far greater than GSK’s capacity.
Outlook: The WHO has not yet endorsed the shot and is still evaluating data from clinical trials. Past reports suggest the shot offers up to 80% protection against the disease. Nigeria and Ghana have both approved the vaccine and regulators in at least 10 other African countries are reportedly reviewing data as well.
BioNTech, best known for delivering the world’s first Covid-19 vaccine given outside of clinical trials with Pfizer, is hoping to turn its mRNA technology against malaria.
Outlook: The German company plans to evaluate different versions of the shot to see what works best and started early stage clinical trials late last year.
Moderna, also buoyed by the stellar success of its Covid-19 vaccine, has also said it plans to pursue an mRNA malaria vaccine.
Outlook: The Boston-based biotech does not list a malaria vaccine as in development in its product pipeline.
News Peg
Researchers in New Zealand and Australia announced a breakthrough malaria vaccine using mRNA technology Thursday. According to a study in Nature Immunology, the mRNA vaccine can stimulate a different part of the immune system than many other vaccines. The shot focuses on developing protective cell-based responses to the malaria parasite that could halt an infection instead throughout the body rather than antibody-based responses that tend to be less useful once the parasite has reached the liver, which it infects as a key part of its life cycle. The University of Melbourne’s Lauren Holz, a research officer at the Doherty Institute and co-author of the paper, said this could potentially “generate a broader and hopefully more protective immune response.” The research is still in its early stages and has not been tested in people yet. After the promising result, the team said they are planning to take the vaccine into clinical trials, a process they expect will take several years.
What We Don’t Know
More than a dozen vaccines are in various stages of development now, though it’s unclear whether they will ever make it to market.
Key Background
Without doubt, malaria ranks among the very worst diseases that strike humanity. It is consistently one of the top causes of death and illness worldwide—alongside tuberculosis and HIV/AIDS, it is considered one of the “big three” infectious diseases—and is one of the oldest recorded human infections. It is a serious and sometimes fatal disease and symptoms include fever, chills, headaches, vomiting and diarrhea. The infection is caused by a parasite and is spread through the bites of infected mosquitos that are predominantly found in warmer, tropical countries. Malaria is largely treatable, though resistance to antimalarial drugs is a looming health crisis, and prevention can be achieved by avoiding mosquito bites with nets or insecticides or by taking preventative medicine. Developing malaria vaccines has, however, proven a formidable challenge to researchers and until recently scientists have struggled to make progress on one for decades. The difficulties largely stem from how tough it is to train the body to defend itself against a complex and moving target like the malarial parasite, of which there are multiple kinds, all of which have evolved to evade our immune defenses and undertake multiple stages of their life’s complicated cycle inside the human body. In addition, immunity does not appear to be lifelong and people who contract malaria can still do so again in the future.
Tangent
Aside from the barriers of technical complexity limiting who can develop a vaccine, the fact the disease primarily affects poorer parts of the world means there are few financial incentives for pharma firms to pour resources into malaria rather than pursuing easier and more lucrative areas.
Big Number
619,000. That’s how many lives were claimed by malaria in 2021, according to the World Health Organization. That year, the agency estimated there were some 247 million malaria cases worldwide. Africa is disproportionately affected by the parasite and the region accounts for the vast majority of cases (95%) and deaths (96%) worldwide, with the majority of deaths occurring among young children. Just two African countries—Nigeria (31.3%) and the Democratic Republic of the Congo (12.6%)—account for more than two-fifths of global deaths.
What To Watch For
Thanks to climate change, many parts of the world are becoming more hospitable to the mosquitos that transmit malaria and experts are concerned it and other mosquito-borne diseases could spread more easily in areas where they have previously been inactive. This includes the United States, which is already a suitable environment for these kinds of mosquitos. Malaria was actually a major public health problem until a successful campaign to drain areas of standing water and wipe out mosquitoes eliminated it in the 1950s. The potential remains, however, and there have been limited signs of the disease’s potential return and domestic transmission in recent years. However, most of the 2,000 or so cases diagnosed in the U.S. each year are in travelers and immigrants coming from countries where transmission occurs, according to the Centers for Disease Control and Prevention.
Further Reading
Why developing the world’s first malaria vaccine has taken so long (Economist)