Episode #35 - Which vaccine should I take and what about side effects?

23 April 2021 | Science conversation

Vismita Gupta-Smith

Hello and welcome to Science in 5. I'm Vismita Gupta-Smith and these are WHO's conversations in science. We're going to continue our conversation on vaccines with Dr. Katherine O'Brien. Welcome, Kate.

Dr. Katherine O'Brien

Thank you, I'm really pleased to be with you again today.

Vismita Gupta-Smith

Kate, in countries where people have a choice of more than one vaccine, they're wondering which vaccine to take. How do experts like you advise them?

Dr. Katherine O'Brien

Well, Vismita, you know, the world doesn't have enough vaccine right now to immunize everybody who needs the vaccine. So, we have a really simple answer to this question, which is when you're offered vaccine, you should take the vaccine that you're offered. We have a number of vaccines that have been demonstrated to be safe, efficacious and to be manufactured with high quality. And so, any of these vaccines are ones that are going to actually protect you. If you live in a country where there's more than one vaccine in the program, you should consider yourself lucky that you have access to the vaccine. And when it's your turn to actually get vaccine, that's the time when you should get it and and accept what vaccine is offered to you. If you're a person in a high risk category and you've been one of the early people to get vaccine, that's something that you should do as quickly as possible so that you're protected. And for people who are later in the queue like me, who work in an office and don't have any substantial high risk exposures, it's just our job to wait our turn. We will get vaccinated and we should accept the vaccine that's offered regardless of what vaccine that is.

Vismita Gupta-Smith

So Kate, when anyone goes for vaccination, they may be wondering about side effects. How do experts understand the risks of these vaccines and how would you explain it, these side effects that you're seeing? How would you explain that to the public?

Dr. Katherine O'Brien

There's a method to look for common side effects in the clinical trials and then rare side effects which are constantly surveyed for in the routine use of vaccines. One of the things that I think people are concerned about is a lot of information in the media recently about blood clots. And this is a topic that the WHO is looking at carefully, regulators in Europe and around the world are looking at very carefully. We're in the midst of collecting information about these very rare events that seem to be happening in the sort of one per million, 10 per million kind of frequency. I think it's important for people to remember that the reason that we're vaccinating is because we're in the midst of a pandemic and we all have risk of COVID infection and COVID disease that exceeds the risk of these very rare events. Nevertheless, what's important is to assess from a numbers perspective, from a risk perspective, the benefit that vaccines confer and the very small risk that these rare events might be associated with vaccines.

So, both regulators and policymakers are looking very carefully at these data, understanding why they're occurring, where they're occurring, in whom they're occurring, and trying to identify whether there are specific groups of people who are more at risk for some of these events, which it doesn't seem to be, and balancing that very rare and low risk against the benefit of protection against COVID disease. People around the world are working together to make sure that information from anywhere in the world is actually collected together and informs our understanding of both risk and benefit. There are regulators in every country and there are policymakers in every country. And there is a system where information is shared up through these regulatory committees and onto WHO, where we also have an external expert group that looks at safety data that's coming in from all parts of the world. So, it is these reviews of the evidence and as that evidence changes over time, where these expert committees on safety make assessments of the benefit and the risk. In addition to that, we also have policymakers who are equally looking at these data and providing not only within countries, but also at the global level here at WHO, through the Strategic Advisory Group of Experts on immunization, recommendations to countries for that balance of benefit and risk and how to minimise any risks that might otherwise be present.

Vismita Gupta-Smith

Thank you, Kate. That was Science in 5 today. Until next time then. Stay safe, stay healthy and stick with science.