Coronavirus (Covid-19) Infection Survey, Northern Ireland: Weekly Report

Date published: 06 May 2022

The Department of Health today published the next in the series of weekly results from its COVID-19 Infection Survey (CIS).

covid latest stats

The findings set out in this report relate to modelled positivity estimates for Northern Ireland for the week up to the 30 April 2022. The aims of the CIS are to estimate how many people have the infection and the number of new cases that occur over a given time as well as estimating how many people have developed antibodies to COVID-19.

The survey over time will help track the extent of infection and transmission of COVID-19 among people in the community population (those in private residential households).

Key Findings

Due to the relatively small number of tests and positive swab results within our sample, credible intervals are wide and therefore results should be interpreted with caution.

  • During the most recent week of the study (24 April – 30 April 2022), it is estimated that 44,900 people in Northern Ireland had COVID-19 (95% credible interval: 34,800 to 56,300).
  • This equates to 2.45% of the population (95% credible interval: 1.90% to 3.07%) or around 1 in 40 people (95% credible interval: 1 in 55 to 1 in 35).
  • Modelling suggests the percentage of people testing positive decreased in the week ending 30 April in Northern Ireland.
  • In the latest six-week period, there were 13,000 swab tests taken in total from 10,898 participants. Of these, 595 participants tested positive from 480 different households.
  • In the latest two-week period, of the 3,832 participants in the study, 122 tested positive from 103 households.
  • In recent weeks, the percentage of people testing positive decreased across all ages.

Variant analysis

The World Health Organization (WHO) have defined names for Variants of Concern. These are variants that the UK government has under surveillance.

Currently, variants under surveillance in the UK are:

  • Omicron: B.1.1.529 (variant of concern), which includes sublineages BA.1, BA.2, BA.3, BA.4 and BA.5
  • Delta: B.1.617.2 and its genetic descendants

The Omicron variant BA.1 has changes in one of the three genes that the coronavirus swab used in the survey tests detects, known as the S-gene. This means the S-gene is no longer detected by the current test. When there is a high viral load (for example, when a person is most infectious), not detecting the S-gene in combination with detecting the other two genes (ORF1ab and N-genes) is a reliable indicator of this Omicron BA.1 variant. However, as the viral load decreases (for example, if someone is near the end of their recovery from the infection), not detecting the S-gene is a less reliable indicator of this Omicron variant.

The Omicron variant BA.2 does not have changes in the S gene, and therefore all three genes, or the S-gene and either ORF1ab or N, will usually be detected in infections with this variant.

Since March 2022 Omicron BA.2 infections have been the most common in all UK countries, comprising 96.1% of all sequenced COVID-19 infections (between 28 March and 24 April 2022).

Given the very high proportion of infections compatible with the BA.2 variant, we have not included a breakdown of infections by variant in this publication. Infections by variant will continue to be monitored and we will reintroduce this analysis when considered helpful.

More information on how variants from positive tests on the survey are measured can be found in the ONS Understanding COVID-19 Variants blog and in the methodology article.

Notes to editors: 

  1. The Department of Health has been working along with the Public Health Agency, Northern Ireland Statistics and Research Agency and the Office for National Statistics (and its various survey partners) to extend the COVID-19 Infection Survey to Northern Ireland. Fieldwork in Northern Ireland began on 27 July 2020.
  1. All results are provisional and subject to revision. Due to relatively small number of tests and positive swab tests within the sample, credible intervals are wide and therefore results should be interpreted with caution.
  1. These statistics refer to infections reported in the community (i.e. private households). These figures exclude infections reported in hospitals, care homes and/or other communal establishments.
  1. Estimates of the total national proportion of the population testing positive for COVID-19 are adjusted to be representative of the population of Northern Ireland that live in private residential households in terms of age, sex and region.
  1. Weekly reports are to be published with findings from the COVID-19 Infection survey. It is anticipated that new and further analyses will be added to the weekly reports over time.
  1. Further information about quality and methodology associated with the survey can be found on the ONS website.

  1. This publication is available online.
  1. Additional information is available from:
    Information Analysis Directorate
    Department of Health
    Annex 2, Castle Buildings
    Belfast BT4 3SQ
    Telephone:  028 9052 2340         E-mail:
  2. For media enquiries please contact the DoH Press Office by email
  1. Follow us on Twitter @healthdpt.
  1. The Executive Information Service operates an out of hours service For Media Enquiries Only between 1800hrs and 0800hrs Monday to Friday and at weekends and public holidays. The duty press officer can be contacted on 028 9037 8110.

Share this page

Back to top