The WHO give an average time for symptoms of COVID to show as being 5-6 days. The 14 day issue comes from a proper abundance of caution. So, given that we are now nearly a month into a gradual reopening of the country, we should be seeing a second wave? We have been told by the public health media that this is “imminent“. One even stated we are in a second wave. This is despite in fact that there is no accepted definition of what actually constitutes a wave of disease. So where are we?
Here we see the full history of cases and deaths since the start. Arguably we already had a second wave, way back in April.
The case 7day moving average peaked on the 19th of April. That is 3 months ago. Death, the 7day moving average peaked the following day. Right now these measures, as of 21 July, are at 3% and 2% of their peaks. This is great, and a testament to the public and the systems put in place, and long may it continue.
Lets look at the period around the reopening on 29 June. Below are the cases for the 21 days before and after that. Remember, the WHO says 5-6 days for cases to show. So if we really were imminently in or actually in a second wave, we would see it now.
So, perhaps indeed we did have an uptick post the 29th of June. Statistically speaking (two tailed t-test assuming hetrogeneity of variances) there is a non zero difference between the 21 days before and after the 29th. The mean daily case number before the reopening was 14, after 16. But this is a very very low incidence of new cases. As I have noted before with low numbers the statistics get fuzzy. We also note that in the last few days we seem to be on a downswing again in case numbers. A run of three days of declining new cases is rare- we have seen it only three times in total, now, and twice back in early May, when the numbers of new cases daily were collapsing. So, we will probably see some more upticks and downticks as this fades, so long as we keep sensible proportional responses in place.
Everybody craves media attention, academics especially as we are mostly (and probably correctly) ignored. Its easy to be apocolyptic. It gets you noticed. Pat Kenny interviews you. You are in the papers, making your Mammy proud. But public health , microbiologists, virologist academics need to remember (or, ask a brod rangeof economists who have been there as a group 10y ago) two things. First, they as experts have a very narrow range wherein they can speak with learned authority. Stray off that and you can get into deep water very fast. Second, the media love to give expert opinion. Professor X says ABC sounds authorative, even if Dr X is say , to pick a not so random example, an expert in the biochemistry of how memory is laid down and is commenting on the need for travel restrictions to be ratcheted up.
We might well get a severe resurgence of this dreaded lurgy. We dont seem to have one yet and there is no clear statistical evidence that one is hiding in the background. Thats about as much as we can say from the data.
As ever all data from the data.gov.ie official covid datasets.