The aim of COVID-19 vaccination is to prevent hospitalisation, severe disease and death. The overall mortality rate associated with COVID-19 has diminished and the demographic profile of those experiencing severe disease has remained relatively consistent. Vaccination induced protection against severe disease wanes over nine to 12 months in most people, but wanes faster in older age groups, particularly those over 80 years and those with immunocompromise.
In 2024, Ireland experienced a peak in cases and hospitalisations during the summer months, and for the first time, did not experience a significant increase in cases in the autumn and winter months (see Figure 1). This uncertainty around seasonality and predicted numbers of peaks throughout the year means that effective vaccination strategies must aim to provide year-round protection against severe disease to those most at risk.
The World Health Organization (WHO) continues to recommend more frequent revaccination, such as six to 12 monthly, in those aged over 75 or 80 years and those with co-morbidities, and annual vaccination in those aged over 50 or 60 years, and in those with co-morbidities. Twice yearly vaccination aims to achieve year-round protection for those in whom vaccine induced immunity wanes faster. Thus, NIAC continues to recommend twice yearly vaccination for a subset of the population at highest risk.
Figure 1: Hospitalised cases of confirmed COVID-19 notified from week 21, 2023 to week 39, 2024 by age. Source: Provided directly to NIAC by HPSC.
For the upcoming spring COVID-19 campaign, NIAC recommends vaccination for those aged 80 years or older, those aged six months and older with immunocompromising conditions and those living in long-term care facilities for older adults. For those aged 70-79, it is important that they continue to receive annual COVID-19 vaccination to remain protected against severe disease. The uptake in this age group during the most recent autumn/winter campaign was less than 50 per cent. NIAC recommends a COVID-19 vaccine in spring for all those aged 70-79 who did not receive a COVID-19 vaccine in the preceding 12 months.
COVID-19 vaccines may be given to these risk groups irrespective of the number of previous doses or types of COVID-19 vaccines, with an interval of six months recommended following any previous COVID-19 vaccine dose or infection. A minimum interval of three months is permissible in exceptional circumstances, for example planned immunosuppressive therapy or operational reasons. Antigenically updated mRNA COVID-19 vaccines are the preferred vaccines for use. Protein based vaccines may be used as alternatives for those in whom mRNA vaccine is contraindicated or declined. Nuvaxovid (antigenically updated) is the preferred alternate.
Seroprevalence surveillance shows that levels of natural immunity are gradually increasing in older age groups. As of October 2024, 82 per cent of individuals aged 80 years and older exhibited evidence of prior natural infection. 95 per cent of individuals aged 18-29 years exhibited evidence of prior natural infection.
During 2023 the JN.1 sublineages were the dominant SARS-CoV-2 variants circulating globally. The KP.3 variant, which is classified as a Variant of Interest (VOI) by both the WHO and the European Centre for Disease Prevention and Control (ECDC) along with its sublineages, is currently the dominant variant worldwide and in Ireland. A newer variant XEC has been steadily increasing in prevalence in Ireland and globally since week 35 of 2024. Currently, there is no evidence suggesting an increase in clinical severity.
“Twice yearly vaccination aims to achieve year-round protection for those in whom vaccine induced immunity wanes faster.”
Uptake of COVID-19 vaccinations during the spring COVID-19 campaign 2024 was estimated to be 44 per cent in those aged 80 years and above; 15 per cent in those aged 70-79 years; and 80 per cent in those living in long-term care facilities. In autumn/winter 2024/2025 uptake was higher than in the spring campaign, and again uptake increased with advancing age.
During the 2024/2025 autumn/winter campaign, the following received a COVID-19 vaccine:
COVID-19 vaccines are safe and the risk of adverse events with vaccination remains considerably less than the risk of adverse outcome with COVID-19 infection and severe disease.
Vaccination provides some protection against infection, which likely wanes within four to six months, whereas protection against severe disease wanes more slowly, over nine to 12 months. Those of advanced age and those with immunocompromise experience more rapid waning of protection against infection and severe disease.
The duration of protection provided by newer COVID-19 mRNA vaccines, including those targeting XBB or JN1 variants, remains uncertain due to the absence of long-term follow-up studies. Consequently, NIAC’s understanding relies on data from earlier original and bivalent vaccines. A 2023 ECDC report emphasised that the time since the last vaccination is more important than the total number of doses received. While the duration of protection varies depending on the vaccine and circulating SARS-CoV-2 variants, a consistent trend has emerged; protection against infection wanes within four to six months, whereas protection against severe disease lasts longer, estimated at nine to 12 months. Protection wanes more rapidly in immunocompromised individuals and older adults, requiring more frequent vaccination to maintain adequate immunity. Those with hybrid immunity, achieved through both vaccination and natural infection, experience the most robust and durable protection.
The recommendations can be access in full at rcpi.ie > Health Leadership > NIAC.
Susan O’Donnell MPSI
Professional Services Pharmacist, IPU
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