The Department of Health today published the next in the series of weekly results from its COVID-19 Infection Survey (CIS).
The findings set out in this report relate to modelled positivity estimates for Northern Ireland for the week up to the 23 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).
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 (17 April – 23 April 2022), it is estimated that 74,700 people in Northern Ireland had COVID-19 (95% credible interval: 60,500 to 91,700).
- This equates to 4.07% of the population (95% credible interval: 3.30% to 5.00%) or around 1 in 25 people (95% credible interval: 1 in 30 to 1 in 20).
- Modelling suggests the percentage of people testing positive in Northern Ireland decreased in the two weeks up to 23 April however the trend was uncertain in the most recent week.
- In the latest six-week period, there were 13,457 swab tests taken in total from 11,165 participants. Of these, 691 participants tested positive from 558 different households.
- In the latest two-week period, of the 3,727 participants in the study, 149 tested positive from 126 households.
- In recent weeks, the percentage of people testing positive decreased among those aged under 75 while the trend was uncertain for those aged 75 and over.
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 compatible infections have been the most common in all UK countries. This was last measured as 96.5% of all sequenced COVID-19 infections (in the four weeks to 25 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.
Notes to editors:
- 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.
- 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.
- 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.
- 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.
- 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.
- Further information about quality and methodology associated with the survey can be found on the ONS website.
- This publication is available online.
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