Covid-19: One-in-four cases in the south had no clear source of transmission

The report said "outbreaks occurred most commonly in private houses".

The Irish Medical Journal report said the number of healthcare workers in the south with Covid-19 was lower than the national average. File Picture.

Covid-19 had a "devastating and disproportionate impact" on older age groups in the south of the country, but the number of healthcare workers affected was lower than the national average and one-quarter of cases did not have a clear source of transmission identified.

The findings are included in a new analysis of the first three months of the pandemic HSE South, which covers Cork and Kerry, published in the Irish Medical Journal.

The first case of Covid-19 in the region was notified on March 5 and, by June 13, a total of 1,842 confirmed cases had been notified, representing 7.3% of cases nationally for that period.

Just over half the cases were female, the median case age was 47 years and the highest number of cases occurred in those aged over 45. It showed that 219 cases (11.9%) were hospitalised, 33 (1.8%) admitted to ICU and 55 cases (almost 3%) died.

Of all cases, just over 73% were symptomatic and almost 41% had underlying medical conditions.

Of those 752 cases, more than a fifth were hospitalised, representing 74.4% of total hospitalised cases, while 4.1% were admitted to ICU and 6.8% died.

As to how the virus spread in those months, ‘local transmission’ accounted for just over 60% of cases, while 26.2% were in a healthcare setting. Around 25% occurred via ‘community transmission’ and 7.4% were imported.

Contact tracing was conducted for more than 4,000 ‘close contacts’ in the southern area and 128 outbreaks were recorded, with 1,259 outbreak-associated cases, occurring in various settings including private houses (56), nursing homes (11), residential institutions (21), hospitals (9), workplaces (8), community hospital/long-stay units (6) and other (17).

"Outbreaks occurred most commonly in private houses (43.8%)," the report said. 

"The highest number of outbreak-associated cases was related to workplace-based outbreaks (25.7%)."

According to the report:  "In our experience, migrant workers, particularly those from non-English speaking communities, are especially vulnerable to household spread and development of familial clusters - due to crowded living conditions and language and cultural barriers. This mirrors international observations. In addition, Covid-19 outbreaks in meat plants pose unique challenges."

The report, written by a team formed from members of the Department of Public Health, HSE South at St. Finbarr’s Hospital, Cork and the School of Public Health at University College Cork, is published at http://imj.ie/covid-19-the-first-100-days-in-the-south-of-ireland/