How one Covid-19 case led to 46 infections and outbreak that lasted a month

The first case, or “index case” they became aware of was a woman who worked in a manufacturing plant.

Household transmission of the virus occurred when a person she was living with, who had acquired Covid in a pub, passed the virus to her.

"The woman then infected a number of others in her shift,” explained Dr Douglas Hamilton, a public health specialist based in the midlands.

“She also infected a specialist who advised across all shifts, which then led to transmission to other cross-plant workers, two other shifts and the admin building.

"The plant closed for a week and cases and close contacts were not allowed to return until their isolation periods were completed.

"This halted transmission within the plant.”

Outside the plant, however, transmission continued, and the outbreak lasted a month.

“The outside transmission, mainly in the households of the affected workers, took some time to peter out,” said Dr Hamilton.

“There were 26 affected in the plant in total, and we identified a further 20 outside it, but there may have been more, including a small nursing home outbreak. There was a sporting event involved, and a pupil in a school was infected.”

The outbreak began before the current lockdown period and continued after Level 5 restrictions were imposed.

“Household spread continued into lockdown,” said Dr Hamilton. “We feel this example is representative of what is happening now.

"Much of the transmission during the current plateau period is household transmission.”

"While health facility, workplace and other clusters are occurring, we are confident that we are getting on top of them.

"However, we do need everyone to accept their responsibility and ensure spread does not continue between households and onwards from there.”

The example of household transmission and how it can lead to infections in various settings comes after the head of the HSE, Paul Reid, said this week that oubreaks in private households were “still very prevalent”.

"Community transmission is still a factor but households are the most prominent one,” he said.