I am glad to have the opportunity to update the committee on the work of the Irish Epidemiological Modelling Advisory Group, IEMAG, and, in particular, to offer some perspectives on the recent increase in the incidence of Covid-19. We need to be aware at all times that statistical analyses and mathematical models provide very useful insights but have important limitations. As such, our input has always been and must always be contextualised within the wider public health expertise available within NPHET.
The strict public health measures put in place between March and June 2020 brought the pandemic under control. As of 18 June 2020, the date of phase 3 reopening, we were detecting, on average, 13 cases of Covid-19 per day and had a 14–day cumulative incidence of 5.2 per 100,000 population. Thereafter, the level of disease continued to decline for one to two weeks such that at the end of June and in early July the average number of new cases per day was ten and the 14-day cumulative incidence was 3.2 per 100,000. We estimated at that point that fewer than one in 30,000 people in the population had an active infection.
However, from late June onwards, we began to see an increase in incidence. This appears to have had three components. First, an increase in viral transmission seems to have begun soon after 18 June, leading to a small, slow increase in cases over the period from 7 July to 20 July. This is understandable and, to a certain extent, was expected. As people increased their numbers of contacts and perhaps began to relax a little with regard to hygiene and physical distancing measures, the virus transmitted more easily. This was associated with an increase in the reproduction number above 1.0, which was clearly flagged to the public in early July. The public seems to have responded by taking added precautions, as case numbers and the reproduction number decreased again towards the end of July.
Second, a number of large outbreaks in counties Kildare, Laois and Offaly, as alluded to by the acting Chief Medical Officer, developed in the week beginning 27 July 2020. These outbreaks were quite explosive, with the virus entering and spreading rapidly within specific workplace settings. Epidemiologically, this acted as an amplifying event and significantly increased the overall burden of disease in the country as a whole and in counties Kildare, Laois and Offaly in particular. The outbreaks were controlled, and significant community transmission prevented, by the outbreak management actions of public health teams, as well as population level public health measures applied in those three counties, as Dr. Glynn mentioned.
Third, since early August and in parallel with these events, we have seen a wide variety of smaller outbreaks with modest levels of community transmission. The cases associated with the major outbreaks to which I referred seeded further outbreaks in households and extended families, but separately, and much more widely within the country, sporadic cases led to household and workplace outbreaks which spread between households and in a variety of workplace, social and sporting settings and, hence, more widely within the community.
The most recent set of public health restrictions to limit indoor and outdoor congregation and mixing between households is specifically aimed at minimising this inter-household spread and keeping community prevalence and transmission to a minimum. It is my evaluation that these challenges were anticipated and detected quickly and that the responses were timely, specific, proportionate and, in so far as we can tell at this time, effective. It should be noted, as Dr. Glynn has done, that similar patterns of resurgent disease have been seen in other jurisdictions in recent weeks.
We are at an important juncture. The next few weeks will show whether we, as a society, are capable of resuming the most important of our social, economic, educational, healthcare, cultural and sporting activities without spreading the virus between households and into our communities to any significant extent. They will show whether we are, as the acting Chief Medical Officer has put it, capable of "protecting our priorities while living with the threat of this virus and keeping it at bay". I would like to record again my appreciation of the team of academic and public service colleagues who support the work of the modelling advisory group, the public health colleagues who work tirelessly to protect us from this virus and, at the same time, provide us with the information that informs our analyses and understanding of the disease, and, like Dr. Glynn, my appreciation of the general public, whose fortitude and solidarity in the face of this crisis are inspirational. I am happy to answer any questions members may have.