Vaccine booster doses not appropriate for general population yet, says review

Lack of need for boosters due to high level of vaccine efficacy, even against delta variant

Booster doses against Covid-19 for the general population are not appropriate at this stage of the pandemic, according to an expert review by international scientists.

This is because the efficacy of vaccines is so high, even for the delta variant, the group, which includes experts from the World Health Organisation and US Food and Drug Administration, says.

Their recommendation comes as Ireland's chief medical officer Dr Tony Holohan gave the go-ahead for booster shots for nursing home residents and older people in the community.

Hospital Report

The boosters will be given "off-label" because the European Medicine Agency has yet to approve the use of Covid-19 vaccines in this way. Dr Holohan acknowledged there was limited data on the safety and efficacy of boosters, and said the contribution of vaccine effectiveness against the delta variant "remains to be clarified".

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Irish officials are also looking at giving booster shots to older people aged under 80, people with underlying medical conditions and healthcare workers, though for now the advice is that vaccines continue to be effective against breakthrough infections in health staff.

The vaccine rollout continued as the HSE recorded its biggest ever day of Covid-19 community testing on Monday with more than 23,000 people tested driven by increased demand among children.

Testing

Niamh O’Beirne, the HSE national lead for testing and tracing, said that it was the largest volume of testing conducted at community test sites during the pandemic.

Cumulatively, there were 41,000 walk-in and self-referral tests of children under the age of 14 conducted over the last seven days, with 6 per cent testing positive for the virus.

The reopening of schools and the circulation of viruses among children mixing again was behind the increase in the Covid-19 testing numbers, Ms O’Beirne said.

The international review on boosters, published in The Lancet, summarises available evidence from trials and studies on the effectiveness of Covid-19 vaccines. It reports an average of 95 per cent efficacy against severe disease, even for the delta variant, and over 80 per cent efficacy against infection.

“Taken as a whole, the currently available studies do not provide credible evidence of substantially declining protection against severe disease, which is the primary goal of vaccination,” said lead author Dr Ana-Maria Henao-Restrepo of the WHO.

The greatest number of lives will be saved by making limited vaccine supplies available to people who are at “appreciable risk” of serious disease and have not yet received any vaccine, she said.

The WHO has argued for a moratorium on booster shots until more people are vaccinated in poor countries with limited access to vaccines.

Dr Holohan based his recommendation on boosters on advice provided by the National Immunisation Advisory Committee (Niac) which, he said, had considered issues of fairness and "moral equality".

In its advice, Niac said it was “mindful” of the lack of doses in low and middle-income countries but warned failure to mitigate transmission of the virus in any country could lead to vaccine-resistant variants.

By limiting availability of boosters to those needing to be protected from severe disease, priority was being fairly given to those “worst off”.

In the UK, children aged 12 to 15 are to be offered one dose of a Covid-19 vaccine, following the latest recommendation by officials.

The decision was taken to help reduce disruption in schools, rather than on purely health grounds. Officials decided against recommending two shots – as in Ireland – due to the very small risk of myocarditis among young people.

Paul Cullen

Paul Cullen

Paul Cullen is Health Editor of The Irish Times

Simon Carswell

Simon Carswell

Simon Carswell is The Irish Times’s Public Affairs Editor and former Washington correspondent