Professor Karina Butler:

All of the issues the Senator brings up are under consideration. What we know is that the use of heterologous vaccines, that is, using a different vaccine for a second or even third dose, actually produces a good immune response. There is some emerging data to show that if a person is given an RNA vaccine in the beginning and is then given a viral vector vaccine like the Janssen vaccine, that can also produce a good response. It does seem that we are gathering enough data to say that from an immune response point of view, if vaccines are mixed in that way people can get a good immune boost. Then it comes down to working out the best way and that data is coming out now. There should be more data available within the next week from studies that are going on in the UK, but for now we are happy to use an RNA vaccine to boost those whom we have said will need a booster, irrespective of whether they have had a viral vector or RNA vaccine.