WHERE ELSE COULD MRNA VACCINES WORK?
Malaria
In 2021, the World Health Organization approved the first mass rollout of a vaccine for malaria, but it’s far from perfect. Although it is not an mRNA vaccine, it reduces disease severity and prevents cases in around 40 per cent of people.
A key problem with making a malaria vaccine is that the parasite responsible for the disease has evolved a way to prevent the immune system from remembering it. Richard Bucala, professor of medicine, pathology, and epidemiology and public health at the Yale School of Medicine, has shown the involvement of a key parasite protein, called PMIF, which suppresses the host’s immune system and prevents it from making key immune cells. Working with the drug company Novartis, Bucala has developed an mRNA vaccine that targets this protein, and which has been shown to help protect mice against malaria infection. Now Bucala has joined forces with scientists at Oxford’s Jenner Vaccine Institute, and they hope to test the vaccine in people later this year.
Multiple Sclerosis
Multiple sclerosis (MS) occurs when the body’s immune system malfunctions and starts destroying the fatty myelin coating that surrounds nerve cells. With assistance from BioNTech, German researchers have devised an mRNA vaccine that encourages the immune system to tolerate the myelin protein, rather than attack it. Research published in 2021 showed that the vaccine delayed the onset and lessened the severity of an MS-like disease in mice.
It’s an encouraging result. Current MS treatments work by targeting the immune system as a whole, which means the drugs often cause side effects. The mRNA vaccine, in contrast, is designed to target only those cells that attack the myelin, so side effects could be minimised. It’s early days, though, and there are, as yet, no clinical trials for MS mRNA vaccines in patients.
HIV
It’s not easy to make an HIV vaccine because the virus mutates quickly, so it’s hard to find a stable target for a vaccine. But Dr Derek Cain from Duke University has shown that some patients with chronic HIV develop antibodies that can neutralise the virus. Unfortunately, the antibodies do little to help the patients because there’s already too much virus in their bodies, but if an HIV-free person could produce the same antibodies, it might help protect them from future infection. Last year, a vaccine based on this idea was tested in a small human trial. In total, 97 per cent of those who received the vaccine produced the immune cells needed to generate the antibodies. “This study demonstrates proof of principle for a new vaccine concept for HIV,” says Dr William Schief, who worked on developing the vaccine.