Covid jab provides strong protection for at least six months post-vaccination
While the jab provides strong protection for up to six months, there was less protection for some vulnerable groups.
The Covid-19 vaccine provides strong protection against severe disease and mortality for at least six months post-vaccination, according to evidence from the Health Information and Quality Authority (Hiqa).
The health authority has published three reviews on the duration of immunity following the jab to inform the work of the National Immunisation Advisory Committee (Niac).
Studies that looked specifically at healthcare workers showed similarly high levels of protection against severe disease to that seen in the general population.
While the jab provides strong protection for up to six months, there was less protection for some vulnerable groups.
Hiqa said that some studies suggest that there is waning protection particularly for older adults and in those with immuno-compromising conditions.
Hiqa added that it is difficult to determine if any reductions in protection are due to waning immunity, differences in exposure, increased transmissibility and or vaccine escape from new variants, or a mixture of all these factors.
“Despite the good protection afforded by vaccination, national and international data indicate a higher risk of severe disease outcomes in older individuals and in those with underlying conditions,” said Dr Mark O’Loughlin, a Public Health Fellow in Hiqa.
"Given this and the potential lower vaccine response for these populations, any additional reduction in protection would be of concern."
Dr O’Loughlin urged people who have been offered a booster to get one.
Currently, healthcare workers, people aged 60 or older, those living in a nursing home or a long-term healthcare facility and people over the age of 16 with an underlying condition are being offered a booster in Ireland.
“There is some uncertainty regarding protection after six months, especially in relation to new variants of concern and changing public health measures," Dr O'Loughlin said.
“We would encourage anyone who has been offered a booster dose, to avail of it and give themselves the best protection possible.”
Of the three reviews, the initial one examined the duration of protective immunity following Covid-19 vaccination in all populations aged 12 years and older.
The first update focused on healthcare workers, while the second update focused on individuals with underlying conditions.
The reviews identified over 50 studies.
