There will be no increase to the four-week gap between doses of Pfizer or Moderna vaccines, despite Government expectations that the space be extended in order to vaccinate more people more quickly.
The matter was referred by Minister for Health Stephen Donnelly to the National Immunisation Advisory Committee (Niac) earlier this month, amid fears over regulatory barriers and supply shortfalls relating to other vaccines.
However, the committee advised that the current gap should not be changed, which was adopted as policy at a Cabinet meeting on Tuesday.
The Minister said earlier this month there was a case to be made for spacing out the doses, and that data internationally and in Ireland showed "incredibly positive signs" in the reduction of cases and hospitalisations from the first dose alone.
However, senior medics and experts had urged caution on the step, saying a significant benefit to the vaccination programme would be needed to justify it.
Elsewhere, Niac advised that all pregnant women should be offered Pfizer or Moderna mRNA vaccines, a policy which was also adopted by the Government.
Previous advice recommended vaccines should be offered to pregnant women at high risk of severe disease and healthcare workers, due to their increased exposure to infection. However, the latest policy development means pregnant women will be able to avail of vaccination even if they are not yet eligible as part of a wider age-based or other cohort.
The Cabinet also approved plans to give those under 50 who have had a recent Covid-19 infection and are not immunocompromised a single mRNA jab, rather than a two-dose regime, as they would have good levels of acquired immunity.
Despite the approval of AstraZeneca and Pfizer vaccine for all people over 50, there was another setback when it emerged that deliveries of the Johnson & Johnson vaccine will be halved this week after a shipment of about 26,000 doses of the vaccine for the Republic was caught up in the fallout from an incident at a US factory producing the vaccine.
It is unclear if the deliveries impacted are only those due this month, which are of lower volumes, or if larger consignments scheduled for the weeks ahead will also be impacted.
The delivery shortfalls arise from an audit by the US regulator – the Food and Drug Administration (FDA) – of a factory where 15 million doses of the vaccine were ruined due to a production error earlier this year.
As a result, Ireland’s second delivery of this vaccine, due this week, will be reduced to about 12,000 doses.
Taoiseach Micheál Martin has said that while there will be a reduction in a coming shipment of Johnson & Johnson vaccines, he is still expecting further large deliveries to come in May and June.
"There has been some reduction in the Johnson & Johnson 12,000 shipment. But the bulk of the Johnson & Johnson vaccine was due in late May and June. The bulk of it is still to come," said Mr Martin.
“ We already have some in the country. There is a reduction in the second shipment but it was low enough anyway to begin with. The key for the Johnson & Johnson is the 600,000 [figure] over the quarter two period, which gives us well in excess of four million vaccines due in that period.”
Mr Martin also said it was “full steam ahead” for the vaccination programme although some time has been lost between the various changes made to the use of vaccines and scheduling.