Coronavirus (Covid-19) Infection Survey - antibody and vaccination data for Northern Ireland

Date published: 30 March 2021

This report is part of the series of Northern Ireland publications from the COVID-19 Infection Survey. Further information can be found on the Department of Health website.

Key Findings

Due to the relatively small number of people who tested positive for antibodies within our sample, credible intervals are wide and therefore results should be interpreted with caution.

• In Northern Ireland, an estimated 1 in 2 people, or 49.3% of the population (95% credible interval: 41.8% to 59.7%) would have tested positive for antibodies against SARS-CoV-2 on a blood test in the week ending 14 March 2021, suggesting they had the infection in the past or have been vaccinated.
• The modelled estimates suggest there has been an increase in antibody positivity in Northern Ireland in the week ending 14^th March 2021.
• The percentage of people aged 70 years and over testing positive for antibodies was 76.4% (95% credible interval: 59.8% to 90.6%) in the week ending 14^th March 2021. The percentage of people testing positive for antibodies in the other age groups ranged from 22.5% to 54.5%.
• The survey provides an estimate of the percentage of people that have been vaccinated however it should be noted that the figures are based on self-report and may differ from figures produced from administrative sources.
• The survey estimates will allow for additional analysis of vaccination information with other characteristics, such as testing positive for antibodies.
• The survey shows that in Northern Ireland, an estimated 58.7% (95% credible interval: 55.2% to 63.2%) of the population have been vaccinated against SARS-CoV-2 in the week ending 20^th March 2021. The modelled estimates suggest there has been an increase in the number of people who have been vaccinated in the week ending 20^th March 2021.
• In the week ending 20^th March 2021, the survey shows the percentage of people who have been vaccinated against SARS-CoV-2 for those aged 70 years and over was 96.5% (95% credible interval: 94.3% to 97.9%). The percentage of people in the other age groups ranged from 12.5% to 73.0%.