11 February 2021

How a holiday affected the spread of COVID-19 in Europe

Decorative: Globe and paper plane
Photo: Colourbox

New research explores the importance of the exact timing of the February 2020 midterm holiday.

A new analysis from the Department of Economics looks into the timing of the February 2020 midterm holiday in relation to the spread of Covid-19 in different regions. The new working paper is based on data from 14 European countries. It shows, that the variation in initial exposure of Covid-19 led to large variations in the size of initial outbreaks, shaping the development of the spread over time:

- Regions with school-breaks just prior to the seriousness on Covid-19 became apparent, experienced larger outbreaks with around 60% higher spread than regions with earlier school-breaks. Furthermore, Covid-19 systematically persists in the regions, that experienced large initial breakouts, with the average spread around 40% higher in the fall and early winter 2020, says Björn Thor Arnarson, Marie Skłodowska-Curie fellow at the Department of Economics at the University of Copenhagen.

He presents the analysis in the working paper: ‘Breaks and Breakouts: Explaining the Persistence of Covid-19’

School-breaks cluster the travel

Björn Thor Arnarson compared different regions within 14 European countries.

He for example compares the February midterm holiday in Gothenburg (week 7 2020) and Stockholm (week 9 2020) (in Swedish: sportlov).

- We know now, that traveling to for example the Alps in week 6 or 7 was relatively low risk, since the spread of Covid-19 was limited, while the same trip in week 9 was more likely to lead to Covid-19 infections as the virus was more widespread. This is significant as the school-breaks cluster the travel by time and location, since not only are you, but also your neighbor, more likely to travel. Having school-breaks in late February or early March therefore led to much higher spread of Covid-19 in those regions, Björn Thor Arnarson explains.

The working paper shows, that when large outbreaks of Covid-19 have occurred in a region, it is very difficult to fully contain the virus.

- We see that the week 9 regions with the highest initial spread are the same that experience the strongest resurgence in the fall and early winter. This high degree of regional persistence highlights the importance of initial action for successful long-term containment. It also indicates that regions that have recently experienced large outbreaks are more vulnerable to further outbreaks suggesting regional prioritization of vaccinations may be warranted, Björn Thor Arnarson says.

He looked into data on the number of Covid-19 cases on a regional level (comparing regions within a country with each other) as well as other datasets on deaths and hospitalizations in relation to Covid-19. The working paper takes into account demographics (age structure), income, density of population and degree of urbanization in the areas.