BOOSTERS ARE COMING. Immunocompromised people across the country look set to receive additional doses of Covid-19 vaccines within the next few weeks, and officials are already looking at the possibility that other patient groups could follow.
No timeline has been set out for the administration of boosters, but Health Minister Stephen Donnelly has said he expects a campaign this autumn, for which his department is awaiting the go-ahead from the National Immunisation Advisory Committee (NIAC).
It comes as scientists and health experts grapple with how to fight the Delta variant of Covid-19, which is more transmissible and which may cause more severe illness in those who are unvaccinated.
Although it was initially expected that most people would only require two doses (or one if they were given a dose of Janssen), Delta appears to have changed the course of the vaccine programme.
Recent studies have shown that the effectiveness of vaccines against the Delta variant reduces over time, and that the efficacy of certain vaccines declines quicker than others - though they still appear to prevent serious illness and death.
But there is extensive debate about whether a third injection is appropriate at a time when two thirds of the world’s population has not even received a first dose.
The World Health Organisation (WHO) has repeatedly called for rich countries to focus on supplying poorer nations, rather than using up vaccines which may better used elsewhere.
Ireland will not be the first country to adopt a policy of supplying booster vaccines to its citizens, but the question on whether to do so is an ethical problem which could have wider implications for how long the Covid-19 pandemic will last.
‘Dual outbreak’
The roll-out of third doses to vulnerable sections of the population will likely coincide with the onset of the winter flu season, when the health service could face extra strain as both viruses circulate.
Similar fears about a ‘dual outbreak’ were raised last summer, months before the emergence of more transmissible strains of concern or the approval of vaccines against Covid-19.
In the end, flu numbers stayed relatively low last winter, largely down to social distancing measures, hand-washing and Covid-19 restrictions.
This year, a wider easing of Covid-19 restrictions is expected ahead of the winter months, which may allow flu to circulate more easily and put more people in hospital, just as it did in the years before the pandemic.
There is another problem too: because Ireland opted to vaccinate people based on age, from oldest to youngest, the efficacy of Covid-19 vaccines may start to wane in elderly people – those most at risk of severe illness and death from the virus – first.
With the highly transmissible Delta variant now the dominant strain in Ireland, there is a fear that older people may be even more vulnerable to Covid-19 than they were a year ago.
Concerns about the Delta variant have already prompted the US government to green-light boosters for all Americans (who, unlike Irish citizens, were not vaccinated based on age) from the end of next month.
The UK is also considering the rollout of boosters this autumn, while Germany, Israel, and France have also begun to offer additional doses to older and immunocompromised people.
The latter group, which includes transplant recipients, was always likely to need a third dose because their initial course of the Covid vaccine would be inadequate.
“We do know at a population level that people who are immunocompromised may not respond as well to the primary course as people have a healthy immune system,” Director of the National Virus Reference Laboratory Dr Cillian de Gascun explained this week.
“Rather than, say, boosting their primary course, what you’re actually doing is completing their primary course. Maybe for certain individuals, two doses may not be sufficient.”
Decisions by countries to boost their general populations have also come on foot of recent research which suggests vaccines are less effective at fighting Covid-19 over time.
On Wednesday, a study concluded that the protection provided by two doses of the Pfizer/BioNTech and the Oxford/AstraZeneca coronavirus vaccines starts to wane within six months.
Scientists behind the study said that the Pfizer jab was 88% effective at preventing Covid-19 infection a month after the second dose but after five to six months the protection decreased to 74%.
With the AstraZeneca vaccine, there was a protection against infection of 77% one month after the second dose but after four to five months, protection decreased to 67%.
Lack of consensus
However, although studies have suggested that vaccines are less effective against the Delta variant over time, they are still good at preventing severe illness and death.
Dr Gerald Barry, assistant professor of virology at UCD, said this week that vaccines still give protection against serious cases of Covid-19 – which is what they were created to do.
“Effectively, these vaccines are designed to protect against severe illness, hospitalisation and death,” he told the Times.
“They’re not designed to protect against infection. That was just seen as a beneficial plus that wasn’t really assessed during the clinical trials.”
Similarly, there is no scientific consensus about when boosters become necessary for those who are not immunocompromised.
In fact, while research shows that vaccine efficacy against Covid-19 falls after a few months, science has not proved that boosters are needed at all: research shows vaccines are about 80% effective at preventing hospitalisation and death.
It raised the question as to whether everyone in the population really needs a booster, or just those who are older and whose vaccine effectiveness will begin to wane into the winter months.
Concerns about the ‘dual outbreak’ of flu and Covid-19 may have passed by the time vaccines are less effective among younger groups, but the pandemic will likely still be ongoing next spring.
At this week’s briefing of the National Public Health Emergency Team (NPHET), Chief Medical Officer Dr Tony Holohan said only that it would be fair to “prepare on the assumption” that people – without specifying who – will need boosters.
De Gascun also suggested that certain tests could be carried out to whether boosters were needed in specific people, rather than re-vaccinating everyone and potentially wasting doses.
He suggested that some people’s primary course could require three doses, whereas others who have a “normal response” may be protected with two doses for one or two years, and then need a booster after that.
“We need to be able to identify whether people have responded to vaccination, and then figure out whether they need additional dosing or not,” he said.
“At the moment, we’re obviously in an emergency setting where we’re vaccinating as many people as possible.
“But hopefully over the next six to 12 months, we’ll be able to dive down more into the finer minutiae and figure out what’s the best vaccine for the best person at the best time, and what the best primary course is.”
Moral and practical dilemma
As that level of research is still being teased out, the twelve-month timeline outlined by De Gascun does not resolve the immediate issue of how Ireland should fight Covid-19 between now and then.
Although using boosters may seem like the safe option in the short-term, doing so presents a moral and practical dilemma.
More than five billion vaccines have been administered globally to date, but wide disparities between rich and poor countries in accessing them persist.
Ireland’s rate of inoculation - 133 doses given per 100 people – is one of the highest in the world, while vaccination drives are not getting off the ground in low-income countries.
The entire continent of Africa has administered just 6.5 doses per 100 inhabitants, ten times less than the world average of 64 per 100 people.
Sub-Saharan Africa’s most populous countries – the Democratic Republic of Congo (0.1 per 100), Tanzania (0.4), Nigeria (1.9) and Ethiopia (2.0) are among the least vaccinated countries in the world, while the likes of Burundi and Eritrea have yet to start.
There are even stark divides within Europe, where more than half the population has received more than one dose: only 16% of Bulgarians and 26% of Romanians are fully vaccinated, compared to 80% of adults in Ireland.
Injections in low-income countries have picked up recently, but WHO chief Tedros Adhanom Ghebreyesus has sought a moratorium on boosters until at least the end of September to allow less wealthy countries to catch up.
The WHO wants every country to have vaccinated at least 10% of its population by the end of September, at least 40% by the end of the year, and 70% by the middle of 2022.
“To make that happen, we need everyone’s cooperation, especially the handful of countries and companies that control the global supply of vaccines,” Tedros said.
Tedros said the G20 group of nations were the biggest producers, consumers and donors of Covid-19 jabs, adding that the course of the pandemic depends on the leadership of these countries.
The WHO’s stance is not just about equity, however.
Allowing Covid-19 to spread unchecked among unvaccinated populations will lead to millions more deaths, as well as increasing the likelihood that another variant of concern will develop – potentially one that usurps Delta and renders vaccines even less effective.
And that’s before taking the economic ramifications into account. A study by The Economist Intelligence Unit found this week that the slow rollout of vaccines will cost the global economy $2.3 trillion (€1.95 trillion) in lost output.
Emerging and developing economies are likely to bear two-thirds of those losses, fuelling resentment and increasing the risk of social unrest in developing economies.
The report’s author, Agathe Demarais, said the international effort to provide vaccines to poor nations, Covax, has failed to live up to its even modest expectations.
“There is little chance that the divide over access to vaccines will ever be bridged,” she warned.
With countries including Ireland set to roll out booster doses in the coming months, that chance is likely to diminish even further.
Contains reporting by Press Association and AFP.
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