Older people, anxiously waiting for a Covid-19 vaccination, could be forgiven for feeling confused about the conflicting guidance on vaccines, especially the Oxford/AstraZenena offering.
The Government/Nphet decision not to offer the latter to over-65s conflicts with other verdicts, including that of the World Health Organisation, which recommends it for over-18s.
In February, the National Immunisation Advisory Committee (NIAC) advised that the Pfizer/BioNTech and Moderna mRNA vaccines be given to those over 70 "where practicable", but that vaccination should not be delayed.
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The Department of Health, on foot of a ruling by chief medical officer Tony Holohan, subsequently adopted a less-nuanced position, saying that only those vaccines should be administered to over-70s.
The WHO's verdict is echoed by the European Medicines Agency (EMA) and its UK equivalent. Nevertheless, Ireland stands with other EU states and beyond in deciding not to use the AstraZeneca vaccine on older people.
Why are there such differences?
Researchers and clinicians who forensically followed the emergence of new vaccines through clinical trials quickly became aware of the limitations and advantages of each.
In the case of AstraZeneca, it was clear that critical phase 3 trials were conducted on younger people first before being extended to older people. Data on the latter was incomplete.
No alarm bells were ringing, though. As more data has emerged, it has shown that AstraZeneca (AZ) does provoke a sufficient strong immune response in older people.
Recommending it for older people, the UK and the EMA believe that any decision to leave vulnerable populations unprotected because of delays in getting other vaccines to them would be too risky.
Vaccine specialist Dr Anne Moore, who is based in UCC, says the bottom line about the AZ vaccine is that "it's safe in all cohorts". Ireland has opted for caution, she says.
Why is the WHO advice significant?
The WHO findings go far beyond recommending the AstraZeneca vaccine for all over-18s. It also recommends that the second vaccine dose be delayed to between eight and 12 weeks after the first jab, backing the UK approach.
And it should be used to combat the South African and other similar variants , while pregnant and breastfeeding women at high risk of illness should be considered too.
Why is the AZ vaccine so important, now WHO has spelt out its view?
It’s cheaper and needs only ordinary refrigeration, and not storage at temperatures of up to minus 80 degrees, so it is the best hope for poorer countries and dispersed populations. And now it can be done through the Covax scheme which enables wide distribution of low-cost jabs. Arguably, it could be the quickest way to gain control of the pandemic.
Should Nphet and chief medical officer Dr Tony Holohan revise their view and resume rollout for older people?
Some doctors do not expect the Irish AZ decision to be reversed. Dr Denis McCauley, chair of the GP committee of the Irish Medical Organisation (IMO), said harder evidence about its value for older people is needed.
“The only thing that would change that is solid evidence that it is effective in the over-65s. The WHO statement doesn’t tell me that.”
Dr Anne Moore believes the Irish decision was correct. Each state must make its own call. “There is more evidence for other vaccines. Clinical decisions should be based on the evidence.”
Facing a global pandemic, however, others see things differently. Paddy Connolly of Age Action said the AZ vaccine should be considered for older people, especially for those who cannot easily get to a GP surgery.
More UK data is due soon, which will help to answer outstanding questions about the strength of immunity offered. In the meantime, NIAC must weigh up the evidence daily.
Should older people be worried about which vaccine they get?
No, frankly. Every vaccine available works, clinicians and immunologists say strongly, preventing serious illness, hospitalisations and deaths. Dr Anne Moore’s advice to her own mother? “Get it in, get it started.”
