With so many updates about coronavirus, it's important to take a moment to understand the latest developments and what they mean for us all. With that in mind, Dr Elizabeth Webb answers 6 of the week's biggest questions.
1. Where are we with coronavirus vaccines?
On Monday 9 November, Pfizer and BioNTech announced early results from the final stage of trials of their coronavirus vaccine, suggesting it may be 90% effective. This is definitely a reason to be cheerful, as it suggests that a vaccine for coronavirus will be possible, and that one may be available soon. However, we need the full and final results of the trial before we can get too excited about this vaccine, as we can’t answer some important questions yet.
2. How well does this vaccine work?
The trial needs to be completed to confirm that the vaccine works as well as the early results suggest. More than 43,000 people are in the Pfizer BioNTech trial, with half given the vaccine and the other half given a placebo (dummy) vaccine. So far 94 people have been confirmed to have coronavirus, with about 10 times as many people who had the placebo getting ill as who had the real vaccine.
But 94 isn’t many, and although it’s unlikely that the apparent benefit of the vaccine is showing up by chance, there isn’t enough data yet to be sure of its exact effect. The full results will be released when about another 70 people in the trial have been confirmed to have coronavirus, which is likely to be in the coming weeks.
3. How does this vaccine protect people?
Vaccines can work in different ways – some just prevent symptoms, while others prevent infection. If a coronavirus vaccine prevented symptoms it would prevent deaths and severe illness among vaccinated people but wouldn’t stop the spread of the disease to unvaccinated people who could still get ill. If it prevented infection and enough people were vaccinated, it would also prevent coronavirus from spreading – we would be able to reach the herd immunity threshold we’ve all heard so much about. It is not yet clear which of these is the case for the Pfizer BioNTech vaccine, and we will have to wait for the full results of the trials to find out.
4. Does the vaccine work for older people?
Vaccines often work differently in older people, as our immune systems tend to work less well as we get older. We don’t yet know whether the Pfizer BioNTech vaccine works well at preventing coronavirus in older people. Again, we will need to wait for the full results of the trials to know more.
5. What about other vaccines?
As we discussed in a previous article, there are a large number of potential vaccines for coronavirus in development. The WHO (World Health Organisation) is now tracking the progress of more than 200 potential vaccines including 47 that are now being tested in people, ten of which are in the final stages of trials. It is likely that more potential vaccines will have early results in the coming weeks and months.
6. How can mutations to the coronavirus affect vaccines?
We also heard this week about a new strain of coronavirus which people in Denmark have caught from mink. Before this there have been lots of other mutations – changes to the genetic code – to the coronavirus but this recent one is the most important so far. That’s because, although this strain doesn’t seem to make people more likely to get very ill than the more common strains, the mutation changes the coronavirus spike protein. This is the part of the virus which sticks out and is targeted by the vaccines which are being developed, so those vaccines could work less well for this new strain. The Danish and UK governments have reacted cautiously and, although it’s too early to be sure, it seems likely that the spread of this new strain of coronavirus is being prevented.
More articles by Dr Webb
Dr Elizabeth Webb is Head of Research at Age UK. She has an MSc in Epidemiology from the London School of Hygiene and Tropical Medicine and a PhD in Social Epidemiology from University College London.