Dr. Anne Moore is a scientist based in UCC with an expertise in vaccine immunology, vaccine stability and infectious diseases. She spoke to RTE´'s This Week to answer some questions about the Covid-19 vaccines which are awaiting regulatory approval. 

Q. Okay Dr Moore, let's start with some basics here...what does a vaccine actually do?

Dr Anne Moore:  So a vaccine is a medicine that teaches the immune system to recognize and to respond to foreign invaders such as viruses. So all of the Covid-19 vaccines, that have been developed for use in Ireland are taking what we call a sub-unit approach, whereby we're just using one protein from the virus. And we're teaching the immune system to recognize that one protein that's within the vaccine so that when the immune system has learned the lesson of that protein and knows how to respond, if it comes in contact with that protein in the context of an infectious virus, it will work to the best way possible and protect protect against infection and disease,

Q: Okay, so that means it will stop you getting sick right? But if you take a vaccine, is it still possible that even though you might not get sick, that you might be carrying the disease and still capable of spreading it to other people?

A: So there's two kinds of questions there. The first thing is the vaccine definitely will not give you Coronavirus. And then the second thing is if you are vaccinated, can you still transmit the virus?  Well the vaccines that have been developed to date have looked at protection against infection. We don't know about whether they'll prevent asymptomatic transmission. And it's unlikely but not impossible that they will function in this way. 

Q:  There are different types of vaccines which will become available if they are approved by regulators. Some are using very new techniques including the mRNA vaccines. Can you explain the differences between the the different types of vaccines that are coming on stream?

A: Sure, so the Pfizer BioNTech and Moderna vaccines as well as the AstraZeneca vaccine all take this kind of genetic instruction approach. So this is where the vaccine contains instructions in the form of nucleotides, a string of nucleotides. That goes into the cell and tells the cell how to make the protein that we're interested in using. So it's a bit like a radio broadcast, the message is given. And then the immune system learns that lesson and the vaccine breaks down and goes away. So these are genetic material based vaccines.

The other vaccines that are in trial, and will probably come along early next year are where we will inject the protein itself into the body.

You mentioned that the Pfizer and Moderna vaccines are using quite new technology. This is correct, but they have been on trial for about five years at this stage, and so far, the safety and the immune responses look really good.

A lab in China working on vaccine development

Q: Some people might be concerned, Dr. Moore, when they hear that this new vaccine technology does something with genetic material in your body? Is there any cause for concern around that?

A: Absolutely not. The genetic material is a very short sequence of nucleotides that can't go into your DNA, it cannot change your cell; it is just a short term message within the cell itself that instructs some proteins in the cell to produce that protein. So it doesn't modify you at all. It's just a very short term message.

Q:  For people who will be getting these vaccines - do we know for how long those people will be protected against Covid-19?

A: At the moment, we don't because the virus has only been in existence since about this time last year. So we're still learning about the virus virus itself. And we just don't have data for people who have been vaccinated, we need time to actually look to see how long they will be protected. A key question here is, what is the minimum amount of immunity that you need to be protected? So if it's a small amount, then it's likely that these vaccines will last for much longer. But unfortunately, only time will tell in this case.

Q:  Some people will have questions and concerns about possible long term side effects. Is it possible to tell whether there could be difficulties or side effects or long term effects for people who take them in months or years from now?

A: Well, for any vaccine, you will generally see side effects quite soon after you've been vaccinated. And there is a huge amount of what we call pharmacovigilance following up on these vaccines now that they're going into the wider community. So generally, you will see anything happen quite soon afterwards, maybe three or four weeks afterwards. And these vaccines even though they're new, they're based on technologies that have been around for a long time. Similar technologies have been used since the turn of the century for the vaccines that are coming online early next year and we have decades of safety data on those. So it should be if there are going to be unwanted effects, we should see them soon after vaccination. 

Q.  The Tánaiste Leo Varadkar told his parliamentary party last week, that it wouldn't be possible to fully understand what rare side effects might exist with vaccines until maybe a million or two million people have taken the vaccine. Is he right there?

A: Yes, he's absolutely right. I mean, you can predict so much when you do a clinical trial. And these vaccines have been tested in tens of thousands of people. At the same time, it isn't representative of everybody who may have, you know, unexpected reactions to the vaccine. So it's only when it goes out into millions of people, that we will see these very, very rare side effects.

Q:  And does the fact that you would need millions of people to take the vaccine before you can see those rare side effects tell you that it would be a very small number of people who are likely to have those side effects?

A: Exactly. And these are risks that we live with every day. I mean, many of us get on flights every day, it's a very small risk that a plane is going to crash. And that's similar to what may happen with a vaccine. It's very, very rare. It's highly unlikely to happen. But we can't rule out that it could happen.

Q:  None of the trials that have taken place so far, as far as I understand it, have involved the vaccine being administered to pregnant women or to children. So do we know whether or not the vaccines are likely to work safely for those categories?

A: We don't know if they'll work safely and effectively in pregnant women and children under 12 and that is one of the reasons why the regulator who is the public's guardian in this context, is not licensing for use in pregnant women, at least in the UK, and it's highly likely that that will happen across the world as well. So until we have got that clinical trial data for pregnant women, and for children under 12, those cohorts will not be vaccinated.

Q: Finally, Dr. Moore, we've seen politicians and celebrities promising to take these vaccines in public in front of cameras to try to encourage others to take them when they do come on stream. Is that a good idea? Do you think?

A: I think it is. I think we need every leader in our community, politicians, sports stars, religious leaders to accept this vaccine and promote this vaccine. And if anybody does have questions, be they sports stars or us regular people in the community, they should definitely ask those questions. It is very important. 

There are two key things here: Firstly it is important that we have trust in what the health authorities are telling us. And secondly, is that everybody in the community accepts this vaccine and that we all agree that taking it is a good thing to do. And leaders across the board, not just politicians are really important to help us to do that.