We should not ignore or dismiss the rising numbers of SARS-CoV-2 infections. We monitor hospitalisations, intensive care admissions, and with great sadness, deaths, and we know where these numbers will go if we do not suppress transmission of the virus. 1/9
Case numbers have been growing exponentially, at approximately 4% per day, since late June. The daily average case count on 23 June was 9 cases. If you add 3.9% every day, you get 12 cases on 1 July, 40 cases on 1 August, 131 on 1 Sept, and 430 today. 2/9
Hospitalisations are delayed, but now also growing at about 4% per day. The daily average number of people in hospital with confirmed SARS-CoV-2 infection on 3 August was 12; increase that number by 4% per day and you get 37 on 1 Sept, and 121 on 1 Oct. 3/9
Log-linear plots, where exponential growth follows a straight line, shows how well this simple exponential fits the data. 4/9
The conclusion is that the epidemic, measured in detected cases and hospitalisations, has been growing exponentially, at the same rate, since July. We have, collectively, had too many social contacts. The virus is transmitting, and cases and hospitalisations growing. 5/9
The restrictions in Kildare, Laois and Offaly worked, and those in Dublin and Donegal may be starting to work, but the virus is spreading at a nearly constant rate throughout the rest of the country. 6/9
If nothing changes, and cases and hospitalisations grow as they have been for the last few weeks, we could see 1200-1300 cases per day and 400 people in hospital by the end of October 7/9
We are seeing people die – mortality with this virus is not negligible and significantly greater than influenza. The only way to protect the vulnerable is to greatly reduce the level of circulating virus in the community. 8/9
This is not meant to scare people. It’s asking us to be honest with ourselves. And it’s not inevitable. On the contrary, if we redouble our efforts to minimize our social contacts, keep our distance when with others, and stay home if feeling unwell, we can beat this. 9/9
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Omicron will be a very significant challenge, but we are acting early, quickly and comprehensively. If we take a booster vaccine when offered, significantly limit contacts, mitigate risk, self-isolate if symptomatic and restrict movements if a contact, we can get through it. 1/22
The purpose of the formal restrictions is to significantly reduce risky social contact, the opportunity for the virus to transmit; they are to reinforce a call to all of us to prioritise our socializing over the coming weeks to a small group of people who matter most to us. 2/22
We already have, by reducing our contacts and adherence to basic public health measures, begun to bring infections and hospitalisations down after a significant surge of the delta variant in early November. This was difficult, but we did it together. 3/22
Let’s think and act positively. We can, with collective action, control transmission of SARS-CoV-2 again, and relieve the pressure of COVID-19 on our healthcare system. The effective reproduction number is currently estimated at around 1.2 1/12
If we can reduce our close social contacts by 30%, and/or mitigate the risks of those social contacts by 30%, we will have done enough to see the level of infection, case numbers and ultimately hospitalisations decline. 2/12
The more we prioritize and limit our social contacts, and mitigate those risks, the faster things will improve. The rising numbers of people in hospital and ICU are an urgent call to action. 3/12
The latest modelling of SARS-CoV-2 infection in Ireland shows that we urgently need to reduce transmission if we are to avoid further dangerous increases in cases and hospitalisations. Stay home with symptoms, limit contacts, use basic mitigations. 1/20
The current surge in disease began soon after the relaxation of measures on 20 Sept 2021, and accelerated from 22 Oct 2021 through the mid-term break. The increase in effective social contact is the primary driver, along with waning vaccine immunity. 2/20
Vaccines are very effective, but over time the immune defence against simple infection wanes. Fortunately, protection from severe disease is well maintained. The waning immunity means that increasing social contact causes a large and increasing force of infection. 3/20
Why are SARS-Cov-2 infections increasing in Ireland? It’s complex, but most likely a mix of increased mobility and social contact since late September, slippage on transmission prevention measures, and more social mixing indoors. 1/16
We had high but stable levels of infection through September 2021, but this was created by a very dynamic and delicate balance between increasing vaccine protection suppressing the virus, and increasing social contact creating opportunities for the virus to spread. 2/16
We started at a disadvantage compared to most of Western Europe. We were hit by a very large wave of delta infections in July, with most of the population under 50 not yet vaccinated, driving daily cases from 300 to 1800 per day between June and August. 3/16
There is no evidence that the reopening of schools has led to an increase in transmission or levels of infection amongst school-going children or more widely across the population. 1/14
The level of infection in children and adolescents had increased in the course of the summer as the delta variant increased the rate of transmission. 2/14
This had stabilized at a high level in children aged 12 and under, and decreased markedly in 13-18 year olds, as vaccination reduced incidence in adults and adolescents, and began to reduce the probability of children becoming infected. 3/14
A lot of commentary saying that most or all schoolchildren will be infected with SARS-CoV-2 in the coming months, based on an uncritical reading of this modelling study. It is highly unlikely that the scenario modelled will happen in the real world. 1/12
First, it’s not plausible. In the 12 weeks after primary schools reopened in March 2021 we detected 5,279 cases in children aged 5-12 years, or just under 1% of the population. The vast majority of these infections were transmitted in the community, not in school. 2/12
Even if delta is 50% more transmissible than alpha, it’s a long way from 1% of the population to 50-75% of the population becoming infected in 12 weeks; note also that most transmission was in the community, and the majority of the community is now vaccinated. 3/12