Dáil Éireann Debate, Wednesday - 19 January 2022
1382. Deputy Peadar Tóibín asked the Minister for Health the length of time the Covid-19 booster will provide immunity for in view of the announcement that boosters will be delivered three months after the second jab. [63054/21]
View answerThe primary aim of the vaccination programme is to protect against severe Covid-19 hospitalisation and death. Secondary aims include reduction of risk of infection and transmission in the population, to maintain healthcare capacity and to help minimise disruption to society and the economy.
To date the National Immunisation Advisory Committee (NIAC) has recommended administration of Covid-19 booster vaccination to everyone over the age of 16 years, to be administered in order of priority and to be given at an interval of at least 5 months since primary vaccination.
Priority for booster vaccines must be given to those at highest risk of severe Covid-19 breakthrough infection i.e., those in the older age cohorts and those with underlying conditions. Booster vaccines should be offered to those in previously recommended groups before progression to the younger age cohorts.
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On 13 December 2021, NIAC updated the advice to the CMO regarding the interval between primary vaccination and the booster dose and advised that this should be shortened to three months. This is in line with recent guidance from the European Centre for Disease Prevention and Control (ECDC). NIAC noted that Ireland is experiencing a high rate of SARS COV-2 infections and the emergence of the Omicron variant gives cause for concern. NIAC considered available evidence regarding the benefit of shortening the interval between primary course and booster vaccination and the benefit of a booster (fourth dose) for those with immunocompromise. Preliminary data indicate that unvaccinated individuals with prior SARS-CoV-2 infection have a three times higher risk of reinfection with the Omicron variant than with other variants. Thus it is important that they are fully vaccinated. Age and immune status remain the dominant risk factors for severe Covid-19 disease. Recent data shows that primary Covid-19 vaccine protection against the Omicron variant is not as robust as that against the Delta variant. Neutralising antibodies against the Omicron variant, can be significantly increased by booster vaccination.
A recent Rapid risk assessment from ECDC in relation to the Omicron variant of concern (VOC) states that vaccination remains a key component of the multi-layered approach needed to reduce the impact of the Omicron VOC, while also addressing the ongoing circulation of the Delta VOC. ECDC recommends that efforts should continue to increase full vaccination uptake in individuals who are currently unvaccinated or partially vaccinated. ECDC states that booster doses will increase protection against severe outcomes from the Delta VOC, and preliminary evaluations also suggest boosters could increase protection against the Omicron VOC. The population impact is expected to be higher if a booster dose is administered to most of the adult population and if this booster dose is given as early as possible, although not before three months after completion of the full vaccination course.
Administration of booster vaccination to those aged 16 years and older in Israel has had a very significant beneficial effect. The rate of confirmed infection in those aged 16 to 49 years in the booster group was at least 10 times less than those who had not been boosted, although follow up was less than three months.
Wider booster vaccination in reducing the risk of breakthrough infection and transmission could help to curb future surges of infection. The duration of protection after booster vaccination is uncertain. However, given the high levels of antibodies achieved and based on experience with other vaccines, it may extend longer than the after a primary vaccination course.
