Professor Karina Butler:

It is a sensible and reasonable question. Basically, that will depend on the information which we will get about all the vaccines. It might turn out, as it did with the hepatitis B vaccines, for example, that there will be different manufacturers and different products but that they will do the same thing. Although there may be an attempt to vaccinate the same person with doses of the same product, it does not matter because the vaccines are interchangeable and any of them can be used. When it comes down to it, in respect of giving someone a hepatitis B vaccine, for example, for most things it does not matter which of two brands on the market are given. Whatever is available at the time can be used.

With these vaccines, we do not have the data yet to say that they are interchangeable. Different types of vaccines are being developed. The first two we have heard about, the Pfizer BioNTech and Moderna vaccines, are the same basic type of vaccines. Even within them, however, there are subtle differences. It might be that, ultimately, they will be interchangeable and it will not matter, but we do not know that yet. When it comes down to it, as well, we will be looking at what data we have on the vaccines and what age groups they might be most effective in.

Some of these types of vaccines might be more effective in older people rather than younger people, and we might choose on that basis. It might also be the case that there may be a difference in the side effect profiles which might favour one group of people over another. For now, however, we do not have the data to comment on one versus another. We really only have data, to any extent, on the Pfizer vaccine, a little bit more on the Moderna and then on the AstraZeneca vaccine. There have been no head-to-head studies on those vaccines. That is a reasonable question from the Deputy, and it is something which will have to be worked out as we get the information to hand on the vaccines.