Sarah Gilbert: Viral Vectored Vaccines
Q: What is a viral vectored vaccine?
SG: Most people will be familiar with live attenuated viral vaccines where we use a weakened form of a virus that would normally cause the disease, to make a vaccine against that disease. For example measles, mumps and rubella vaccines are an example of mixing together three live-attenuated vaccines to make vaccines against those three diseases. What we’re doing now is taking different viruses and making them really safe to use in people but then adding in parts of pathogens so we can make new vaccines against those other pathogens. For example we could take a virus that would normally cause a cold and we could add in parts of the malaria parasite to make a vaccine against malaria. Or we could take a safe version of the vaccine that we use against small pox and add in parts of the flu virus to make a new flu vaccine.
Q: Why should we use these vaccines?
SG: What these viral vectored vaccines are really good at doing is inducing T cell responses in the person that we vaccinate. So a lot of the vaccines that we use are protein and adjuvant vaccines and they’re very good at inducing antibodies against the protein that’s used in the vaccine and that’s helpful against protecting against some diseases. But for other diseases we need to engage the other major part of the immune system and that’s the T cell response. Viral vectored vaccines are really good at doing that and we need that for some particular diseases such as malaria and some viral diseases. They’re also useful for vaccinating against cancer. Viral vectored vaccines can also induce antibodies so we can get both an antibody and a T cell response at the same time.
Q: How far has this research progressed?
SG: Within the Jenner Institute over the last few years we’ve done about 50 different clinical trials of viral vectored vaccines for different diseases mainly in malaria but also against tuberculosis, HIV, influenza, hepatitis C so we’ve come a long way in understanding how to use these viral vectored vaccines in people.
Q: What are the most important lines of research that have developed in the past 5 or 10 years?
SG: Going back to about the last 50 years, we were using vaccines that were really effective but often had some nasty side effects; for example the small-pox vaccine gave people a very unpleasant scar and could have some very serious side effects in some cases. So there was a big emphasis on improving vaccine safety. Unfortunately when we developed safer vaccines we ended up with some vaccines that were less effective than we could have had before. In the last 5 or 10 years we have been concentrating on making vaccines that are extremely safe but also have a high-level of efficacy and we are able to do that with these viral vectored vaccines. The compromise seems to be that we probably have to give more than one injection but the pay-off is that we get a very safe and very effective vaccine and we can use the technology to make vaccines against lots of different diseases. We’ve also become much better at understanding how T cells can protect us against disease and how to induce them by vaccination and how to measure if they’re doing their job.
Q: Why does your line of research matter, why should we put money into it?
SG: We still need a lot more vaccines that we can use to vaccinate against diseases like malaria and HIV where we don’t have a vaccine at all. For other diseases like tuberculosis and influenza we do have vaccines against but they’re not particularly effective, especially in older people and we need to do better. If we can use viral vectored vaccines to make new vaccines that work in a different way we can really improve public health.
Q: How does your research fit into Translational Medicine within the department?
SG: Our research is very translational because a lot of it involves doing clinical trials of our new vaccines in volunteers. We have a clinical bio-manufacturing facility that can make the batches of vaccines we need for clinical trials in carefully controlled conditions and we also have a pre-clinical viral vectored core-facility that makes us lots of small batches of vaccines throughout the early stages of our research. We can also offer that service to other researchers that want to collaborate with us. Information about that is on the Jenner Institute website.