The world’s first mRNA vaccines – the COVID-19 vaccines from Pfizer / BioNTech and Moderna – made it through the laboratory in record time through successful clinical trials, regulatory approval and in humans’ arms.
The high efficacy of protection against serious diseases, the safety seen in clinical trials, and the speed with which the vaccines are designed will change the development of vaccines in the future.
Once researchers have introduced the mRNA manufacturing technology, they can produce mRNA against any target. The production of mRNA vaccines also does not require living cells, which makes it easier to produce than other vaccines.
Thus, mRNA vaccines could potentially be used to prevent a range of diseases, not just COVID-19.
Remind me again, what is mRNA?
Messenger ribonucleic acid (or mRNA for short) is a type of genetic material that tells your body how to make proteins. The two mRNA vaccines for SARS-CoV-2, the coronavirus that causes COVID-19, produce fragments of this mRNA in your cells.
Once inside, your body uses instructions in the mRNA to make SARS-CoV-2 proteins. So if you find the proteins of the virus again, your body’s immune system will already have an advantage in dealing with it.
What mRNA vaccines are researchers working on after COVID-19? Here are three that are worth knowing.
1. Flu vaccine
Currently, we have to set up new versions of the flu vaccine every year to protect us from the strains predicted by the World Health Organization (WHO) during the flu season. It is an ongoing race to monitor how the virus develops and how it spreads in real time.
Modern are already focusing their attention on an mRNA vaccine against seasonal flu. It is aimed at the four seasonal strains of the virus that will be predicted by the WHO.
But the holy grail is a universal flu vaccine. It will protect against all strains of the virus (not just what the WHO predicts) and therefore you do not have to update every year. The same researchers who pioneered mRNA vaccines are also working on a universal flu vaccine.
The researchers used large amounts of data on the influenza genome to find the mRNA code for the most “highly conserved” structures of the virus. It is the mRNA that is least likely to change and leads to structural or functional changes in viral proteins.
They then prepared a mixture of mRNAs to express four different viral proteins. These include one on the stalk-like structure on the outside of the flu virus, two on the surface and one hidden in the virus particle.
Studies in mice show that this experimental vaccine is remarkably strong against various and difficult target strains of influenza. It is a strong claimant for universal flu vaccine.
Read more: A single vaccine to defeat all coronaviruses sounds impossible. But scientists are already working on it
2. Malaria vaccine
Malaria caused by infection with the unicellular parasite Plasmodium falciparum, delivered when mosquitoes bite. There is no vaccine for it.
However, US researchers working with the pharmaceutical company GSK have filed a patent for a mRNA vaccine against malaria.
The mRNA in the vaccine encodes a parasite protein called PMIF. By teaching our bodies to target this protein, the goal is to train the immune system to eradicate the parasite.
There have been promising results of the experimental vaccine in mice, and early stages of human trials are planned in the UK.
This malaria mRNA vaccine is an example of a self-amplifying mRNA vaccine. This means that very small amounts of mRNA have to be made, packaged and delivered, as the mRNA will make more copies of itself within our cells. This is the next generation of mRNA vaccines after the ‘standard’ mRNA vaccines seen so far against COVID-19.
Read more: COVID-19 is not the only scientist looking for a vaccine. Here are 3 more
3. Cancer vaccines
We already have vaccinations that prevent infection with viruses that cause cancer. Vaccination against hepatitis B, for example, prevents types of liver cancer and the human papillomavirus (HPV) vaccine prevents cervical cancer.
But through the flexibility of mRNA vaccines, we can think more broadly about tackling cancers that are not caused by viruses.
Some types of tumors have antigens or proteins that are not found in normal cells. If we could train our immune systems to identify these tumor-associated antigens, our immune cells could kill the cancer.
Cancer vaccines can target specific combinations of these antigens. BioNTech is developing one such mRNA vaccine that shows promise for people with advanced melanoma. CureVac developed one for a specific type of lung cancer, with results from early clinical trials.
Then there is the promise of personalized mRNA vaccines against cancer. If we can design an individualized vaccine that is specific to each patient’s tumor, we can train their immune system to fight their own cancer. Various research groups and companies are working on this.
Yes, there are challenges ahead
However, there are several obstacles you need to overcome before using mRNA vaccines more widely against other medical conditions.
Current mRNA vaccines should be kept frozen, limiting their use in developing countries or in remote areas. But Moderna is working on developing an mRNA vaccine that can be stored in a refrigerator.
Researchers should also look at how these vaccines are administered in the body. While injection into the muscle works for mRNA COVID-19 vaccines, delivery in a vein may be better for cancer vaccines.
Read more: 4 things about mRNA COVID vaccines that researchers still want to find out
The vaccines must be shown to be safe and effective in large-scale clinical trials in humans, before being approved. Since regulatory bodies around the world have already approved mRNA COVID-19 vaccines, there are far fewer barriers than a year ago.
The high cost of custom mRNA cancer vaccines can also be an issue.
Finally, not all countries have the facilities to make large-scale mRNA vaccines, including Australia.
Regardless of these barriers, mRNA vaccine technology is described as disruptive and revolutionary. If we can overcome these challenges, we can possibly change how we make vaccines now and in the future.