Covid-19 booster shots for nursing home residents and other older people are to be given “off-label” because of the lack of authorisation for this use, according to the chief medical officer.
Those receiving booster doses should be provided with whatever evidence is available about their safety and efficacy as part of an informed consent procedure, Dr Tony Holohan says.
Dr Holohan has accepted the recommendation of the National Immunisation Advisory Committee (Niac) that boosters be given to residents aged 65 and older in long-term residential care and to those aged 80 and over living in the community, no sooner than six months after they received their regular second dose of the vaccine.
All vaccines and other medicines have to be licensed for use before they can be administered, but sometimes they can be used in a way that differs from the normal authorisation if medical experts recommend this.
In a newly-published letter to Government, Dr Holohan acknowledges there is limited data on the safety and efficacy of Covid-19 booster doses, and says the contribution of vaccine effectiveness against the delta variant “remains to be clarified”.
While vaccines remain effective against hospitalisation and severe illness, there is some “attenuation” of their effectiveness against infection, and this may wane over time, he says.
"Data from the US and Canada signal a concerning trend whereby the proportion of breakthrough cases increases with age and are highest in those aged over 80 years, with protection against hospitalisation as a result of Covid-19 reduced in those over 75 years."
Separately, data from Israel shows those aged 60 years or older who were fully vaccinated in March were 1.7 times more protected against severe Covid-19 compared to those fully vaccinated two months earlier. Over 1.5 million booster doses have been administrated in Israel to date with no safety concerns, Dr Holohan points out.
The European Medicines Agency has not yet authorised booster doses for any Covid-19 vaccine, though it has begun assessing data on boosters for the Pfizer vaccine.
“In light of the current epidemiological situation, and in order to provide earliest protection to the groups identified by Niac as requiring a booster dose, implementation of these recommendations may require an off-label use of mRNA Covid-19 vaccines (Pfizer and Moderna).”
The World Health Organisation has called for a moratorium on boosters until more of the world's population get access to initial vaccine doses to protect them against the virus.
Dr Holohan says that in making its recommendation, Niac gave consideration to global vaccine equity and “upholding the principles of minimising harm, fairness and moral equality”.
In its recommendation, Niac says it is conscious of the global demands on vaccine supplies and recognises that facilitating vaccination on a global level “is not only important on a humanitarian and global equity basis, but essential to limit the threat of Covid-19 to our own population”.
It is also “mindful” that low and middle-income countries have insufficient doses to protect those most at risk; less than 2 per cent of people in these countries have received a first dose of vaccine.
"Ending the global pandemic is a universal goal and vaccination is a collective project. Failure to mitigate high community transmission of SARS-CoV-2 in any country through vaccination and other non-pharmaceutical interventions can create selection pressure for vaccine-resistant variants, prolonging the threat of the virus in Ireland and globally."
“In restricting booster doses to those for whom the evidence indicates that it will be safe, effective and is required to protect them from severe disease, the principle of fairness (which is related to distributive justice and equity), is realised, as priority is given to those worst off.”