COVID vaccine rollout: who's getting what?

There's been much to celebrate. 90 year old Margaret Keenan has become the first person in the world outside of a clinical trial to receive Pfizer’s COVID-19 vaccine. But this is merely the start of a long journey to get these vaccines to millions of people across the UK, and then billions around the world. What's the plan, and which vaccines will go where? Michael Head is a Senior Research Fellow in Global Health at the University of Southampton, and answered these questions for Chris Smith…

Michael - Well, this is a wonderful day for science. It's a wonderful day for research and it's a wonderful day for the UK National Health Service. But of course, this is very much just a starting point. We need to vaccinate the entire country and we need to vaccinate the entire world as much as we possibly can. So there is still a lot of work to do from here, but this is an excellent start.

Chris - Indeed. I think Andrew Pollard from the Oxford vaccine group described it as analogous to being at Everest base camp.

Michael - Absolutely. So we've dragged ourselves up a little bit of the mountain. We've cleared some rather forbidding looking cliffs at the bottom of it, but the peak is still away in the cloud at the very top. So there is a long way to go: 16 billion doses of a vaccine to cover the entire planet.

Chris - Talk us through then what really we've got to do here in the UK to begin our ascent of the peak.

Michael - So we are starting with healthcare workers, care workers, and very soon in the next week or two vaccinations will be taken into care homes. There's then other older populations and people who are particularly clinically vulnerable. Beyond that, it will be rolled out to the rest of the population.

Chris - Do we have any plans or clear guidance yet as to how they intend to do this? Because we've got a vaccine here that needs to be kept at minus 70 degrees until about the last five days, during which you intend to use it. It comes in batches of 975 doses, which means you've got to basically have a queue with that number of people in it to avoid wasting any vaccine. These are quite a lot of constraints.

Michael - Absolutely. So the initial plan was that care home residents would be in the very first wave of vaccinations, but due to these logistical constraints around the minus 70 degrees storage, that's been postponed for a week or so whilst the fine tuning of the logistics are being worked out. The Pfizer candidate, wonderful though it is, does come with extra challenges that some of the other vaccine candidates don't.

Chris - Well, you've brought up the question of other vaccine candidates. Can we talk now about the AstraZeneca offering? They have published a paper in The Lancet this week in which they give some of the data from their phase III trial. Is there anything in there which we need to be aware of?

Michael - So the findings that were published in The Lancet today reflect what was mentioned in the press release about three weeks back. So there's no real surprises. So we can see, for example, that the average effectiveness is around 60 something percent. But if you take the - as it turns out - accidental small dose, and then scale up to a full second dose, that raises the effectiveness to about 90%. The problem we have is there's not too much data about these doses in the elderly, the older populations. And the accidental dose there again, there's not too many people who were given that dose. So it certainly looks very, very promising. And I think we probably will see it approved at some point. Maybe pre-Christmas, if not very early in the new year.

Chris - What appears to have happened is, according to AstraZeneca, a subgroup of people in their trial got a smaller dose than they should have done when they were first given the vaccine. And then they got the full dose next. Why should there be a better response, a 90% outcome instead of a 60% outcome in terms of protection, when you do it like that?

Michael - Well it's a very intriguing finding. And I think we're still waiting to really find out why. The theory is that the first, smaller dose primes the immune system, and then you get a much better, stronger response when you add the second dose. It remains to be seen precisely what immunological curiosities are going on there. But that's the theory right now, as far as I understand it.

Chris - The problem, as I see it, is that people will see the Pfizer data and it says, "this is 95% effective" or so we presume. And they'll see the AstraZeneca data and it might be as low as 60%. For a vaccine that's still pretty good, isn't it? But people will say, "well, hang on that doesn't look as good as the other one. So I want the Pfizer one". Is this going to create a problem, a two tier system, perhaps? A postcode lottery even, for who gets what? And therefore could that lead to problems?

Michael - There may be some tensions. So I think we do need to be prepared for that. I think what people are probably hoping is that the 90% effectiveness as referred to in the Lancet paper for that small dose followed by full dose from the Oxford candidates, people are probably hoping that that comes to the fore. And is the answer in terms of, "what effectiveness is the Oxford candidate?".

Chris - The other question, which is coming up quite a lot, is this uncertainty around whether or not someone who has been vaccinated can still nevertheless, catch the virus. Now, why is that uncertainty arisen? Why are people who are vaccinated not completely protected? And is this just a theoretical risk? Or do you think actually there probably is something in this?

Michael - So with the Oxford AstraZeneca candidate, they've been testing their study participants weekly. So we can look at asymptomatic transmission. So although the vaccine protects you from getting ill, it may not protect you from getting infected and theoretically being able to pass it on, which is what we think may be happening with the Pfizer vaccine. It prevents you from getting ill, rather than preventing you from getting infected.