web analytics

COVID-19 in Scotland: perhaps some optimism and some caution

Glasgow / Scotland – April 2020: Elderly Woman Shopping in Glasgow Wearing PPE Protective Mask During Coronavirus Covid-19 Pandemic Beside Ross Muir Square Gogh And These Days Will Pass Fly Posters

For the first time in 19 months, I feel a bit more optimistic about the COVID-19 pandemic. Yes, the pandemic is still raging and the number of cases – and deaths – in England and in Wales is still climbing up. Yes, the cases are going up across Europe. Yes, a lot of these new cases are among those vaccinated. Yes, we have a difficult winter ahead, with seasonal flu possibly returning with a vengeance and Respiratory syncytial viruses spreading into a population with much lower immunity.

But, looking at the newest Scottish data, I really start feeling like the worst is behind us. I have so far been very cautious with predicting what might be happening ahead. In fact, in many views exchanges, it was me who was advocating caution and pouring cold water on any hopes of “herd immunity”.

I still believe that “herd immunity” is a highly confusing term, to the point of being unhelpful in the current outbreak. I have written about it (again) in The Conversation article. The title of this article (added by the editor) has not perhaps aged well – relaxation has brought a spike in cases – but I was making a point there:

Although repeats of large waves from last winter or last summer are unlikely, bringing down case numbers will be challenging. For some countries, like the UK, high levels of infection will probably persist for the foreseeable future.


Despite the increasing numbers in England and Wales – possibly at least in part caused by the Test and Trace system fiasco – I still stand by this statement. The newest Scottish data seem to confirm this:

Scotland’s cases (black dots and blue lines) and deaths (red dots and red lines). Lines showing 7 days running mean.

The spike caused by the beginning of the school year (16th August) seems to be going down in children and young adults, although the cases have now stabilised. The older population (45+ years old) has experienced a delayed peak (an “echo” of the school-driven outbreak) followed by another small peak (return to work?), but again the numbers are not spiking up. Again, in The Conversation:

What we’re seeing now may be what the pandemic looks like in the weeks and months to come. Outbreaks may well be limited, with an increasing proportion of cases in the vaccinated population, simply because almost everybody is already vaccinated.


But of course, the cases are not going down either. This also seems to confirm what I said in my article:

What’s almost certain is that the pandemic will have a long tail that is massive and uneven, and which is likely to have a disproportionate impact on the vulnerable, those living in deprived areas and pregnant women. It’s also clear that vaccination alone won’t be enough to suppress the virus. Simple restrictions, like masks, vaccine passports or frequent testing, will continue to be part of our lives.


So – it is currently still quite an unstable situation, but perhaps there is a hope that the worst excesses of 2020 and early 2021 are not going to repeat themselves this winter.

But, I can be completely wrong.

Video on my research on trees and forests

This time, not on COVID-19, but on my other topic of interest.

I am talking about my love of trees and my research on forests, as part of the UKRI (UK research agency) showcase for COP26.

In this video, I am not addressing controversial aspects of climate change and its causes. But I love trees and I hope that my research will help to protect them and to let people enjoy them.

COVID-19 lessons from Scotland

Edinburgh / Scotland – March 23 2020: Edinburgh’s much loved Greyfriars Bobby statue protected with face mask during the COVD-19 pandemic

I have recently been looking at the age-structured COVID-19 data from Scotland, particularly analysing the latest wave. I think the last couple of months – and especially the last week or so – teach us a lot about the virus spread in highly vaccinated populations.

The size of the outbreak in school-age children is staggering. Possibly there was some under-reporting back in the first or second wave in these age groups, but the latest outbreak is definitely fueled by cases among young people, with some spill-over to the parent – and grant-parent – generation. Compare the peaks this September with the first and the second wave in the graph below:

The proportion of cases and deaths in different age categories in Scotland: black/blue: cases; red: deaths. Points: raw data, lines: 7 days average

At the same time, vaccines are clearly working – the death rate, particularly in 60+ age classes, is much smaller relative to what we did see in the pre-vaccination time. Again, compare the red points in the graph above, in the first and the second wave versus the current, third, wave – a similar number of cases resulting in much fewer deaths.

This is clearly the result of a fantastic roll-out of vaccines, in all – except the youngest – age groups, as shown below:

The proportion of people in age classes with one or more vaccine doses (blue line) and two vaccine doses (red line).

Two things are concerning. The delay in vaccinating young people – and the lack of proper control measures in schools like masks and ventilation – clearly allowed a massive epidemic in these age groups. The deaths were only very few, which is why this epidemic is not getting enough attention in the media, but the consequences in terms of long term complications – “long COVID” – might be massive. In addition, the vaccination progress in the youngest groups is slowing down and reaching a plateau at 70-80% – way too low to make an impact!

Secondly, as seen below, the rapid decline in cases which we saw in the last couple of weeks is slowing down. The virus seems to be bouncing back as the cases actually go up in some age classes (particularly older). This could be because the immunity is waning and we see more breakout cases, but more likely this is a reaction of the epidemic to relaxation of the rules.

The proportion of cases and deaths in different age categories in Scotland: black/blue: cases; red: deaths. Points: raw data, lines: 7 days average

The graph below captures this recent change using the 7-days ratio between cases (a rough estimate of the reproductive number). The value below 1 means the case numbers are declining, and the value above 1 means the case numbers are accelerating.

The ratio of cases delayed by a week for different ages. Points: data, line: 7 weeks running average. The horizontal line at 1. The vertical line at 16th August when schools started.