The Health Information and Quality Authority (HIQA) has said there is consistent evidence that Covid-19 clusters most commonly occur in household settings, and that there is a higher rate of onward transmission in households, compared with other settings.
HIQA makes the observation in the advice it submitted to the National Public Health Emergency Team (NPHET) on higher risk activities and settings associated with Covid-19 transmission.
The advice published today also says that "activities involving dining, drinking, exercising, singing or shouting, prolonged face-to-face conversation, especially in indoor crowded environments, were associated with an increased risk of transmission in several studies".
HIQA looked at 19 different international studies involving 60,000 people who contracted the virus, to compile advice for the National Public Health Emergency team.
"A range of public health measures, such as use of face coverings, physical distancing, hand washing and improved ventilation, may reduce some of the transmission risk," HIQA states.
It goes on to say that while there is consistent evidence that the risk of transmission is "substantially lower" in outdoor settings, clusters in outdoor environments "have been observed", particularly when there are large gatherings, limited social distancing, dense congregation, and mixing among groups.
The research found that clusters are also "consistently observed" in other places including nursing homes, meat and food plants, large shared accommodation, nightclubs, bars, restaurants, gyms, offices, prisons, shopping centres and religious settings.
The report said that many of these settings and activities have been associated with "super spreading events" and have "seeded" large numbers of cases.
HIQA said the findings support NPHET's current stance on settings and activities presenting a high risk of transmission.
It also highlighted the need for Irish data regarding settings and activities linked with an increased risk of transmission in order to better understand the national risk and mitigation factors.
Fatigue not responsible for stalled progress in suppressing second wave
A leading behavioural scientist has said he does not believe 'fatigue' is the reason behind stalled progress in suppressing the second wave of the virus.
Professor Pete Lunn of the ESRI said evidence suggests that compliance with public health measures is not primarily driven by fatigue, but rather by a "perception of risk".
Prof Lunn said that as the case numbers here started to fall quite quickly, "maybe we did see a relaxation in peoples' efforts".
Now that the "numbers have stalled", he said, hopefully people can "redouble their efforts and we can get this second curve down".
Reacting to the research and advice published by HIQA today, Prof Lunn said research like this is important to the general public.
"It reinforces some of those key messages about avoiding circumstances where we are indoors, where there is poor ventilation, where there are many people and it is difficult to socially distance.
"When those factors come together that is where the highest risk is."
While the expert community can see multiple risks factors, individuals can sometimes underestimate these, he said.
The HIQA research said that there is consistent evidence that the risk of getting Covid-19 outdoors is substantially lower than indoors.
Prof Lunn said this backs up ESRI research on this subject.
"It doesn't mean there can't be transmission, but it substantially reduces the risk.
"What we find is that members of the public underestimate that difference compared to the expert community. It's not perfect but getting outdoors reduces the chance you get this disease."
Call for people to stick to self-isolation guidance
Dr Máirín Ryan, HIQA's Director of Health Technology Assessment and Deputy Chief Executive, said: "The international evidence highlights that the main factors that contribute to spread of Covid-19 are indoor settings, crowds, and prolonged contact with others.
"Much can be done to mitigate risk in these settings, such as ensuring good ventilation and people following public health advice to use face coverings, keep physical distance and wash their hands frequently."
Dr Ryan said: "Our findings reinforce the importance of adherence to self-isolation guidance, despite the challenges it can pose, for those with Covid-19, those awaiting test results and those with symptoms suggestive of Covid-19.
"This means following the HSE guidance on self-isolation including staying indoors, in a room with a window you can open, and completely avoiding contact with other people, including where possible other household members, for at least 10 days."
HIQA said that self-isolation guidelines should be applied due to the higher risk of transmission within households and that compliance could be improved by providing different supports for those who are unable to safely self-isolate at home.
HIQA also highlighted the need for communication campaigns to focus on the settings and activities conducive to transmission, the concept that there are different levels of risk, how to reduce risk and the importance of adhering to self isolation guidelines.
The number of Covid outbreaks identified in households has more than doubled in the space of a week, according to the latest Health Protection Surveillance Centre data.
The data shows 954 clusters were notified last week in relation to private houses. This compares to 443 household outbreaks for the previous week.
A cluster, or outbreak, is when two or more cases of the virus are discovered.
We are concerned about the current profile of #COVID19 in Ireland and we are asking people to stick with the public health advice over the coming weeks and months.— Dr Ronan Glynn (@ronan_glynn) November 18, 2020
However, there are many reasons for us to be hopeful as we look forward into 2021...
Elsewhere, Deputy Chief Medical Officer Dr Ronan Glynn has said there is concern about the current profile of Covid-19 in Ireland and the Department of Health is asking people to stick with the public health advice over the coming weeks and months.
In a series of tweets, Dr Glynn said that there are many reasons for us to be hopeful as we look forward into 2021.
He said: "our collective effort: The efforts of the majority have sustained our response from the start.
"People continue to make very significant sacrifices, to do the right things, protecting themselves and their families, but also for the greater collective good of their wider community.
"Over the next two weeks we must continue to drive down this disease in our community, to once again stop #COVID19 in its tracks."