An outbreak of 59 coronavirus (COVID-19) cases has been linked to an international flight into Ireland, according to a report released in infectious disease journal Eurosurveilance last month. Following the flight, which took place over the summer, thirteen of the 49 passengers onboard tested positive for COVID-19. Another 46 laboratory-confirmed cases were linked to contact with those individuals. The aircraft was at just 17 percent passenger capacity and the study noted that nine of the 13 passengers who tested positive were wearing masks, one was not, and mask use was unknown for three. The affected airline and the origin of the flight were not disclosed in the report.
“This outbreak demonstrates the potential for spread of SARS-CoV-2 linked to air travel,” researchers stated in the report. “Onward transmission from 13 passenger cases resulted in a total of 59 cases in six of eight HSE [Health Service Executive] health regions in Ireland, necessitating national oversight of the outbreak. We calculated high attack rates, ranging plausibly from 9.8% to 17.8% despite low flight occupancy and lack of passenger proximity on-board.”
Researchers were unable to identify the source case for the outbreak but found that two people became symptomatic within 48 hours of the flight and three additional case were confirmed within five days. Genetic sequencing of five samples from individuals linked to the outbreak showed a greater than 99 percent similarity in the viral strain found in each, “strongly suggesting” a single source of infection. Researchers contributing to the study were affiliated with Ireland’s Department of Public Health and Health Protection Surveillance Centre (HPSC).
The full text of the report can be viewed here.