The Government’s decision to expand the Covid-19 booster vaccination programme is surprising at this point in time, according to immunologists, who recommend waiting for Omicron-specific vaccines.
On Saturday, Minister for Health Stephen Donnelly said second booster doses would be offered to people aged 50-64, and those aged 12-49 who have underlying medical conditions or live in long-term care facilities.
Healthcare workers and pregnant women will also be offered a second mRNA booster vaccine, while the over-65s and those who are immunocompromised and aged 12-64 will be offered a third booster dose.
The decision, made by the National Immunisation Advisory Committee (Niac), and endorsed by the interim chief medical officer, differs from that of European health agencies, which say there is “no clear evidence” to support second boosters for under-60s or healthcare workers without underlying conditions.
Kingston Mills, professor of immunology at Trinity College Dublin, said the “bottom line” was that no number of doses of the current vaccine would prevent infection.
“The companies are making BA.5- and Omicron-specific vaccines. They won’t be ready for some time. They’re likely to be better, obviously, at inducing immunity against the circulating strains than the current vaccine,” he said.
“I think the real important thing is going to come in the autumn and to get people boosted with a version of the vaccine that is more likely to protect them against the current circulating strain of the virus.”
Reservations
Prof Mills said getting infected with the virus now provided better immunity than a vaccine based on the original virus from two years ago.
While acknowledging the need to protect vulnerable people, he said he would “start to have reservations about five doses so quickly”.
“That has to be weighed up against the risks that the uptake will be poor now and will be poor in the autumn.”
Paul Moynagh, professor of immunology at Maynooth University, said that although the booster made sense for the over-65s as it gave added protection, the question now was what was going to be achieved by extending the campaign and going for repeated boosters.
“The question really is: are we going to continue to go down the road of boosting every three to four months, and whether that’s going to be effective. Are we seeing diminishing returns with these repeated boostings?” he said on RTÉ Radio’s Morning Ireland.
Prof Pete Lunn of the ESRI’s behavioural research unit said there was a risk of lower uptake of the booster coming out of a recent surge in transmission.
However, he added that in May, when the epidemiological situation was positive, 82 per cent of people still said they would receive another vaccine.
“I would anticipate, because we have seen it before, that willingness to take a booster is going to depend on the perception of the seriousness of the disease currently, and what I mean by that is how many people are ending up in hospital,” he said.
Latest figures indicate the country is now past the peak of the most recent wave, which was largely driven by the highly transmissible BA.4 and BA.5 Omicron sublineages. The number of patients with Covid in hospitals has fallen from more than 1,000 two weeks ago to 635 on Monday morning.
