ABSTRACT
BACKGROUND: In May 2021, the B.1.617 variant of SARS-CoV-2 emerged in Ireland, and both Delta and Kappa sub-lineages were initially deemed variants of concern (VOCs) on a precautionary basis. We describe a large outbreak of SARS-CoV-2 B.1.617.1 (Kappa mutation) linked to a private gathering among third level students in Cork, Ireland. METHODS: Surveillance data were available from the Health Service Executive COVID Care Tracker. The epidemiological sequence of infection for each new case in this outbreak was tracked and whole genome sequencing was requested on all linked cases. Enhanced public health control measures were implemented by the Department of Public Health HSE-South to contain onward spread of VOCs, including retrospective contact tracing, lengthy isolation and quarantine periods for cases and close contacts. Extensive surveillance efforts were used to describe and control onward transmission. RESULTS: There were 146 confirmed SARS-CoV-2 cases linked to the outbreak. All sequenced cases (53/146; 36%) confirmed Kappa mutation. The median age was 21 years (range 17-65). The majority (88%) had symptoms of SARS-CoV-2 infection. There were 407 close contacts; the median was 3 per case (range 0-14). There were no known hospitalisations, ICU admissions or deaths. Vaccination data was unavailable, but the outbreak pre-dated routine availability of COVID-19 vaccines among younger adults in Ireland. CONCLUSION: Enhanced public health control measures for new and emerging variants of SARS-CoV-2 may be burdensome for cases and close contacts. The overall public health benefit of enhanced controls may only become apparent when evidence on disease transmissibility and severity becomes more complete.
ABSTRACT
This study reviewed the epidemiology of confirmed cases of coronavirus disease 2019 notified in the department from 5 March-13 June 2020. The first case of COVID-19 in our region was notified on 05/03/2020;by 13/06/2020 a total of 1,842 confirmed cases had been notified, representing 7.3% of cases nationally for that period. Epidemiological curves (epi-curves) were constructed using 'epidemiological date' (epi-date) and 'notification date'. These epi-curves are more closely aligned from May 2020 onwards, which likely reflects expedited testing/reporting processes. Of note the HSE South 'epi-date' curve diverges downwards from the national pattern in late-March 2020, which is early in the overall evolution of the pandemic in Ireland. In our study 1,115 cases (60.5%) occurred through 'local transmission', 482 (26.2%) in a healthcare setting;471 (25%) occurred via 'community transmission';137 (7.4%) were imported. Contact tracing was conducted for >4000 'close contacts' of confirmed cases. One-hundred-and-twenty-eight outbreaks were recorded, with 1,259 outbreak-associated cases, occurring in various settings including;private house(56), nursing home (11), residential institution (21), hospital (9), workplace (8), community hospital/long-stay unit (6), unknown (0) and other (17). Outbreaks occurred most commonly in private houses (56, 43.8%). The highest number of outbreak-associated cases was related to workplace-based outbreaks (324, 25.7%).