Why this year’s bivalent Covid-19 booster vaccines offer improved protection

Professor Robin Shattock, the head of mucosal infection and immunity within the department of medicine at Imperial College London and one of the first researchers to work on Covid-19 vaccines, explains the benefits of the latest bivalent booster vaccines in this Trust interview.

What are the benefits of bivalent booster vaccines for Covid-19?

We anticipate that the bivalent booster vaccine will give people a broader response to the virus than previous boosters.

I suspect that everybody's fairly familiar with the fact that the virus is changing over time. When we wanted to produce an immune response through the original vaccine, it was very much focused on the first strain that came out in the pandemic, what we call the Wuhan strain, A, or the alpha strain.

By giving the immune system a bivalent vaccine that targets both the original and Omicron strains, we’re giving the immune system a wider diversity of targets, so it makes antibodies that are more effective as the virus will likely continue to change over time.

Why does the booster continue to target the original strain if that strain is no longer circulating?

We know the vaccine against the original strain works extremely well and is still working to prevent serious disease. All the efficacy data we have is based on that original strain. So boosting that original response as well as then inducing a wider immune response is the best of both worlds.

Should I be concerned about having the Moderna or Pfizer-BioNTech booster vaccines if I previously had vaccines produced by a different company?

No, this new vaccine has an excellent safety record. It's no different in terms of the side effects to the original Moderna and Pfizer vaccines, which have now been taken by many, many millions of people. We really have an excellent understanding of the safety profile of these vaccines.

Is it worth getting one of these boosters even if new strains become more prevalent this winter?

It's definitely worth getting that booster because this updated, bivalent booster will broaden your immune response. Even if the virus continues to change, you're going to be in a better position with having that wider immune response than if you either relied on previous vaccination from some time ago, or just had a single booster with the original vaccine.

If I’ve recently had Covid-19, is it still worth getting the booster vaccine?

It's definitely still worth getting the booster. If you have recently had Covid-19, the NHS recommends waiting about 28 days after your first positive Covid-19 test before getting your booster. That's not to do with safety, it's just to do with getting a stronger boosting effect.  

Were there any ill effects reported from administering Covid-19 booster vaccines and flu vaccines together last year?

No, that works extremely well and there didn't seem to be any complications. We didn’t have any concerns in terms of safety or in terms of the immune response generated against flu and against Covid-19. Administering them together provides no negative outcome and is much more convenient.

Do the vaccines affect fertility, pregnancy or breastfeeding?

There's been an enormous number of studies showing the vaccine has absolutely no impact on fertility. It is also safe in pregnancy and during breastfeeding. I think people should be very reassured now we really understand that it's safe for those groups now. We have abundant evidence that the Covid-19 vaccine – as well as the flu vaccine – are safe and in fact recommended for those who are pregnant.

There was never any indication that the Covid-19 vaccine was unsafe for those who were pregnant or breastfeeding, but initially it wasn’t recommended because we didn’t have the evidence to confidently recommend it. It was just a matter of being cautious and making sure we had enough evidence to prove it is safe before recommending it. Now we know it is safe for those who are pregnant, which is why the Royal College of Obstetricians and Gynaecologists recommends the Covid-19 vaccine during pregnancy. 

If I’ve had both vaccines, last year’s booster vaccine and Covid-19, do I really need to have this year’s booster?

The Covid-19 vaccine is good at preventing serious illness. We suspect that it reduces, even in people who have a mild infection, the amount of time that they are infectious. If you are a healthcare worker or if you're living with vulnerable people and you've had the vaccine and you still contract Covid-19, the vaccine will likely reduce the duration of the infection and your ability to pass it on to others. It will also reduce your risk of severe disease.

Will we need to continue to have Covid-19 booster vaccines every year?

I think it's very likely that, in years to come, we will see booster campaigns for the elderly, those with vulnerabilities and healthcare staff and professionals that are working with vulnerable populations. This is very much in line with flu vaccination and that's why it's great news that you can give both together. We’re not having to ask people to come back twice, you know, once for a flu shot and then once for Covid-19 shot.

Visit the NHS website to find out if you are eligible to get the Covid-19 booster and flu vaccines and where you can get both.