The Covid vaccine booster campaign is more important than ever amid uncertainty surrounding the Omicron variant, according to an immunologist.
A number of countries, including Ireland, have introduced new travel restrictions since the emergence of the new variant, first identified in South Africa.
The first case of the Omicron variant in Ireland was identified on Wednesday.
While there has been talk of tweaking vaccines to deal with the variant, or developing a new one, it is too early to say whether this will be the case.
Professor Ed Lavelle, head of the school of biochemistry and immunology at Trinity College Dublin, told BreakingNews.ie: "The booster campaign is more important than it ever was, nobody should wait.
"Even in the worst case scenario if this looks significantly different and the antibody responses aren’t as well-matched as they were, it’s not like a totally different virus, you’re still going to have a degree of recognition, so what we need is as many people in the population as possible having the highest antibodies possible.
"Nobody should be sitting back and thinking of waiting for a new vaccine, that would be a disastrous approach, people need to take the vaccines we currently have because they will give a degree of protection, hopefully as high as possible."
While the strength of the Omicron variant is still unknown, Prof Lavelle feels a lot more will be known within the space of a few weeks.
"I think we’ll know some of it fairly quickly, what’s going on at the moment is once the strain is identified, taking samples from people who are vaccinated or who have been infected with the Delta strain, and looking at whether their antibodies are capable of recognising this one and in relative terms how well that’s been recognised compared to the previous variants.
"That will inform a lot of decisions. If that suggests it is evading responses they will start trying to make new vaccines."
Spike protein mutations
He explained that most of the current Covid vaccines create antibodies that can fight the spike protein in coronavirus, however, the Omicron variant has mutations in the spike protein which could make it more resistant to vaccines.
"The current vaccines are still targeting the original strain, they did give a good degree of protection against Alpha and Delta. What people are trying to find out now is whether the antibodies those vaccines produced are capable of protecting against this variant or not, that will be an indicator in terms of how protective the vaccines are likely to be.
"We have a couple of arms of the immune response; when you get vaccinated you make antibodies and T cells that can kill virally infected cells and can wire up your immune system to be more effective, so we need to find out whether the antibody responses are equally able to recognise this variant and later whether the T cells can also recognise it.
"If it turns out that the antibody recognition is much lower, clearly that’s bad news. The question then will be whether we need to re-formulate [the vaccine]. We didn’t make new vaccines against Alpha or Delta. If it’s more pathogenic and evading the immune responses, then we need to start making vaccines to target it.
What's next
"The concern all the time is what’s coming next. The vaccines made a year and a half ago are still working well, you don’t want to shift all production to this one and then find in six months’ time you’ve got a different variant that can evade this response, that’s the difficult balance to strike. You want to make a vaccine that’s going to give you the best coverage.
"The tricky thing with this is we don’t know what’s coming next, but the good news is the original vaccines have continued to work well against a number of variants that have come up in the meantime.
"What we’re hoping to see with Omicron is that will continue to be the case. There are some people suggesting because of the number of mutations there’s a higher chance that this will evade antibody response, but we just need to wait and find out."
The decision will have to be made whether it makes sense to make a new vaccine for this variant.
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Prof Lavelle said Moderna chief Stéphane Bancel's comments about the likelihood of the current Covid vaccines being less effective against Omicron were worrying.
However, he stressed that the current vaccines are working well and there is still a good chance they will offer protection against the new variant, even if they are not "perfectly matched" with its mutations.
"The decision will have to be made whether it makes sense to make a new vaccine for this variant, it could be that the variant you’ll have by the time you’ve made and rolled out the vaccine will be a different one. What we need to have in the population is the highest level of coverage with as many people as possible with high titres of antibodies because even if they don’t stop you getting infected, the likelihood is it will be enough to prevent a high percentage of the population getting sick.
"Even if the current vaccines aren’t perfectly matched for this variant, there’s a high degree of immunity in the population that wasn’t there at the beginning. We’re in a better position than we were at the start of the pandemic and decision-making has sped up.
"The ideal scenario is we find out this isn’t as big a problem as we feared, but it could be a massive problem, and you can’t afford to sit around for even a month for the data to come in.
"The vaccines we have are still working well after a year and a half despite changes to the virus, so they’re extremely effective, it’s a matter of how you design the next one if you re-formulate it. The beta strain we were concerned about, and it didn’t turn out to be as big of an issue as we’d feared in Ireland and Europe, it depends on if this one is with all these factors, how much can it evade immune responses, how transmissible it will be."
Prof Lavelle said newer and more sophisticated vaccines are constantly in development.
He explained that a nasal vaccine could be key for future control of the pandemic, and other respiratory illnesses.
However, this is still a long way away.
Nasal vaccine
"The advantage of a nasal vaccine would be immune responses in the blood and respiratory tract, so it could stop infection and transmission. Unfortunately we’re not really close to that, but long term the only way out of it might be a nasal vaccine, or booster for people who have been vaccinated, that could stop transmission. Otherwise, the virus is going to keep circulating.
"Historically almost all vaccines are injectable, the only widely used nasal vaccine is the flu vaccine given to children, but in vaccine development this is the challenge we have to solve in the next few years, how do you develop new approaches. It won’t be as simple as putting the existing vaccines up the nose, that won’t work, you have to develop a different type of vaccine that will work well nasally.
If the predictions about Omicron are right, the degrees of protection may be lower so if you’re looking forward if vaccine boosters are annual they will not be the same as the ones we have now.
"That’s what we’re realising with viruses that are transmissible, if people are carrying this in their noses and spreading it, finding a vaccine that can stop that would be brilliant. Injectable vaccines have still worked well, early on they seemed to block infection well then over time they still stop people getting very sick and dying, but they won’t block transmission effectively in the long term, so I think we should be prioritising mucosal vaccines."
Prof Lavelle said it is too early to say whether booster vaccines will be needed annually, however, he said future vaccines are likely to be different to the ones currently in circulation.
"The reason we have to boost every year with flu is that the virus changes significantly from year to year so the immunity you have from the previous year wouldn’t be well enough matched against what’s coming at you the next winter, if that’s the situation with Covid it could be annual boosters. What we’re hoping for is effective global coverage can reduce the degree of variation in the virus, but that’s all unknown at the moment.
"If the predictions about Omicron are right, the degrees of protection may be lower so if you’re looking forward if vaccine boosters are annual they will not be the same as the ones we have now. Whether the vaccine has to be updated every year is the big question, if the virus doesn’t change then you can use the same vaccine, if it changes it will have to be updated.
"The vaccines we have are still working well after a year and a half despite changes to the virus, so they’re extremely effective, it’s a matter of how you design the next one if you re-formulate it."
