The news from Europe in recent days has been dominated by the almost exponential rise in the number of Covid-19 cases across several Western European countries. What is the size of this problem and more importantly why is it happening? Is it too simplistic to focus on vaccination rates?
What is the data on cases
- In the graph below I have extrapolated from Oxford University’s Covid-19 data website (Our World in Data) trends in the fortnightly rate of cases over the past 2 months in some selected countries
- There is no doubt that especially in the past month there has been a phenomenal rise in the rate of cases (ie allowing for the population size) in Austria, Netherlands, Belgium and, though not at the same speed of rise, Germany
- Data in recent days suggest possible rises in Southern European countries
- The exception is the UK which has rates that are remarkably steady but, by comparison with countries outside Europe (and indeed over the 24 months of the pandemic) high
What about the rates of severe cases?
- Much of the growth in the number of cases could be explained by 2 issues that would not be so worrying:
- Greater publicity leading to increased testing of the population thereby identifying more milder/asymptomatic cases
- Greater numbers of infections in younger people, given their greater social mixing at school and higher education, and whose infection is less severe
- However, the increases in the number of cases above are mirrored by an increase in the number of deaths
- Again, the figures in the graph below take account of different population size in each of these countries
- For completion I show similar data for hospitalisation
*Data from hospitalisations in Germany at a national level are not available (to me anyway!)
Is it all vaccination rates?
- Regular readers of this blog and other media sources will be aware that vaccines are great at preventing severe infection but less good at preventing all transmission
- In all these countries the severe cases are indeed concentrated in those who have not been vaccinated
- Thus differences in vaccine uptake might explain some of different trends in these countries: but what do the data actually show?
- The answer in regards to the question above is very little: vaccine rates are not that different between countries
- Other data I have seen suggest that in comparison with the UK, the rate of fully vaccinated people is only 4% less in Austria and 1% less in Germany
- The conclusion is not that vaccination rates need to be higher in these countries (which they do) but rather that differences in vaccine rates do not explain why these sudden rises are happening now
Are there different strains at play?
- Throughout this pandemic the concern has been that different strains of the virus, resulting from mutations, could explain higher rates of cases
- Indeed the Delta variant, with its much higher rate of transmission, has explained the second and especially the third wave of cases seen in many countries
- It has also been, what was an unexpected observation, that there have been no major new strains emerging during 2021 since and the Delta does still predominate in all the European countries
- A variant of Delta, called AY4.2, is becoming more common (around 15% of cases) and might be more transmissible, but at the moment this is not thought to explain these recent trends
- It is also reassuring and needs repeating (!) that contrary to initial worries, the vaccines used today are still based on the original Wuhan strain of the virus and yet still protect against both Delta and the AY4.2 variant
What about mask wearing?
- Of all the mitigation measures, mask wearing is the most effective at reducing transmission
- Could differences in mask wearing explain the trends?
- We know that research suggests infected people are less likely to have been wearing masks than their contacts who remain well
- It is difficult though to obtain data that are meaningful about who wears a mask and in what circumstances.
- There are some survey data on mask wearing behaviour from different European countries which are interesting
- Without doubt the population from Southern European countries are more likely to wear masks but Netherlands and Germany have higher rates than UK (I don’t have Austrian data)
- I don’t think mask wearing explains all the trends but these data are supportive of that hypothesis and logically that could be the case
- For sure the trends in some European countries are worrying but also unexplained
- I suspect there are worse data to come both in terms of more deaths and hospitalisations, as well as rises in other countries
- Vaccines, and especially boosters will help prevent these rises translating into public health and health service crises
- Covid-19 is re-writing the rule book on how epidemic viruses behave!
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