What’s in the pipeline? The future of vaccine development

Vaccination research is always evolving, harnessing new technologies to help reduce the burden of several diseases or to eliminate them entirely from our communities.

Since the first vaccine was developed in 1796, scientists have searched for new ways to protect people against infectious diseases through vaccination. While some deadly or highly debilitating diseases can now be fully prevented through vaccination, others still kill thousands of people around the world every year, such as malaria. Research and development of new vaccines, alongside access to existing vaccines, therefore continues to be a public health priority.

We now have six vaccine technologies – or platforms – that researchers use to develop vaccines. Some of the most promising advances in vaccine technology include mRNA and DNA vaccines. These technologies have the potential to lead to breakthroughs beyond infectious diseases, for example for the prevention or treatment of certain types of cancer.

mRNA vaccines

Messenger RNA, or mRNA, technology has been in development and under research since the 1960s.The first trials of mRNA vaccines explored how it could be used in the prevention of Ebola. With the COVID-19 pandemic, these early efforts shifted to address COVID-19. The first mRNA vaccine approved for use in Europe was in 2020 against COVID-19.

mRNA technology has also been tested in clinical trials against other infectious diseases such as influenza, RSV and ZIKA.

mRNA technology has been looked at since the 1970s to develop vaccines against some forms of cancer such as melanoma and lung cancer and even new forms of cancer treatment. The technology has enabled research breakthroughs in helping prevent recurrences of aggressive cancers after surgery as well as teaching the body to attack some types of cancer before they have a chance to grow.

DNA vaccines

DNA vaccines, also known as plasmid vaccines, work by delivering short DNA sequences into our body that contain the instructions for producing antigens from a specific a virus or bacteria. Once the vaccine is in the body, our cells use the DNA sequence and start producing these antigens. This enables our immune system to learn to recognise and fight the disease should we ever be exposed to it.

One of the potential benefits of this approach is that the immune system’s response can be much stronger than with other types of vaccine. DNA vaccines are also more stable and easier to produce than mRNA vaccines as they do not need to be kept at temperatures well below freezing, which would greatly improve access.

The potential for DNA vaccines was first discovered in the 1980s. DNA vaccines are still being researched and none have been approved for use in humans in the EU/EEA yet. Clinical trials are underway around the world to investigate their safety and efficacy against several infectious diseases. DNA vaccines were first used in animals in 1993 and some DNA vaccines have been approved for use in animals in the United States and the EU/EEA. In 2021, India approved the first DNA vaccine for use in humans to protect against COVID-19. DNA vaccines have the potential to unlock a wide range of possibilities not currently available, including a vaccine against HIV, among other conditions.

As with all vaccines and other medications in Europe, DNA vaccines will have to demonstrate that they are safe and effective before they are approved for use in humans.

New forms of vaccine delivery

Despite the fact that vaccines are safe, effective and economical, needles can be intimidating, especially for children. There is a great deal of research ongoing into innovative ways to administer vaccines. Some possibilities include:

Oral vaccines are already in use and have long been considered very promising as they are cheap, easy to administer, and can be extremely effective. An oral polio vaccine was launched in the 1960s and oral polio vaccines are still in use today.

However, they are not without their challenges. Our digestive system is inhospitable, stomach acids can damage or destroy vaccine components and they are not always well absorbed in our intestines.

Researchers are now looking at new ways to protect ingredients in oral vaccines and improve absorption by encasing the vital components in a microscopic protective layer. This would mean the vaccine retains its effectiveness despite the harsh conditions it encounters in the digestive system.

Nasal sprays have the advantage that they do not require any specialised training, meaning people could even vaccinate themselves quickly and easily. The nose is full of blood vessels near the surface and below a porous membrane, meaning it is a highly effective way of getting a vaccine into the body. As the nose is a very common way for viruses and bacteria to enter the body, nasal sprays also have the advantage of boosting the immune response where it may be needed most.

Nasal spray vaccines have already been approved in the EU/EEA against the flu in children; they are being actively researched for other respiratory viruses, such as COVID-19.

Researchers are also exploring ways of painlessly delivering vaccines through the skin in jets of high-pressure air or by using ultrasound waves to help a liquid vaccine enter the body. Both options have shown promise as the area under the skin is considered an ideal place for many vaccines to interact with the immune system. However, challenges remain as our skin is not of uniform thickness. These methods of delivery are also considered expensive when compared to traditional injections or with nasal sprays.

This technology consists of dozens or hundreds of tiny needles so short they pierce the skin without causing any pain. These needles enable a vaccine applied to the skin to pass through and into the body. While it may not mean an end to the use of needles, it would eliminate the visual sight of a large needle and the pain associated with traditional injections. Some studies have also shown that this technology could enhance efficacy.

Electroporation has also been shown to be a potential way to replace syringes. This works by applying a small amount of electricity to either drive a vaccine into the body or temporarily ‘open’ cells up to a vaccine.

How vaccines work

Vaccine safety and side effects

Benefits of vaccination

What’s in the pipeline? The future of vaccine development

mRNA vaccines

DNA vaccines

New forms of vaccine delivery

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