The future of vaccination

Vaccination is one of the most successful forms of disease prevention available today, resulting in the complete eradication of some diseases and successful control of others. However, there are still plenty of opportunities to make vaccines even better.

New ways of using and delivering existing vaccines are in development, while research continues into creating new vaccines to target an even broader range of diseases.

New ways to use existing vaccines

We can make existing vaccines even more effective by finding smarter ways to target specific at-risk groups in society. For example, giving a vaccine with a killed pathogen to a pregnant woman will boost antibody levels in the mother, allowing the extra antibodies to reach her unborn baby. Doing this protects her newborn while the baby’s immune system is still maturing, providing the baby with immunity from birth.

When a pregnant woman is successfully immunised against a disease, she can pass protective antibodies to her unborn child. Image adapted from: Valeria Zoncoll; CC0

Another way to use existing vaccines more effectively is by targeting them to the elderly. For instance, elderly people in hospitals are more prone to several vaccine-preventable diseases such as Streptococcus pneumoniae, influenza virus and shingles-causing varicella.

New technologies for vaccine delivery

For a vaccine to effectively stimulate a protective immune response, it needs to get past one major barrier: the skin, which is our body’s first line of defence against disease. This is why so many vaccines need to be injected under the skin into muscle.

A fear of needles can be a major barrier for many people when it comes to getting a vaccination. Fortunately, new technologies are under development that will mean fewer injections (such as by combining several vaccines into one shot), or even using technology that uses no needles at all!

Some vaccines can already be delivered orally (polio vaccine) or via a nasal spray (influenza vaccines). Researchers are also working on innovative delivery methods such as needle-free skin patches and microneedle injection technologies for a less painful vaccination experience.

Some vaccines can already be delivered without the need for injections. Image adapted from: Thorsten Frenzel; CC0

New vaccines

Current research is aiming for entirely new vaccines and improved versions of existing vaccines. For example, vaccines against influenza currently need to be re-developed each year to keep up with the ever-changing virus involved. However, a universal influenza vaccine could be on the way as researchers find different ways to target the virus regardless of these changes.

Most successful vaccines work by prompting our immune system to produce antibodies against a target disease. However, for some diseases, standard approaches don’t work so well, either because our immune system does not respond as it normally would, or because a pathogen finds other ways around our defences. HIV/AIDS and malaria are two examples of diseases which are notoriously difficult to vaccinate against thanks to rapidly-mutating pathogens that can also ‘hide’ from key parts of the immune system.

Nevertheless, there is now a licensed vaccine for malaria that provides at least partial protection against the disease. Scientists also continue to make progress towards developing an experimental HIV vaccine for use in clinical trials.

Immunisation still has so much more to offer global health in both developed and developing countries around the world

Vaccines also have the potential to treat, in addition to preventing, both infectious and non-infectious diseases. Such ‘therapeutic’ vaccines are being targeted at persistent infections (such as shingles and human papillomavirus-induced tumours) and at non-infectious conditions, including autoimmune disorders, allergies and other cancers that are not known to be infection-related. These vaccines may work by amplifying the body’s anti-tumour immune response, or (in the case of autoimmune or allergic disorders) by switching off the unwanted immune responses responsible for these conditions.

Immunisation still has so much more to offer global health in both developed and developing countries around the world. Thanks to vaccination, we’re now so much closer to a world without polio—who knows what other diseases we might be able to eradicate forever in the future?

This is part of a series of articles on the science of immunisation funded by the Australian Government.

This article has been reviewed by the following expert: Professor Tony Basten AO FAA FTSE Emeritus Professor of Medicine, Central Clinical School, Centenary Institute of Cancer Medicine & Cell Biology, University of Sydney.

Source: www.science.org.au