Mandatory vs recommendation: Norway assessed mobility during times of mandatory and non-mandatory COVID-19 measures

Norway, like other Nordic countries, widely utilised non-mandatory advice during the COVID-19 pandemic in the attempt to reduce social contacts among people and occasionally turned to obligatory measures, specifically during peaks in transmission. In comparison with stricter interventions, non-mandatory measures are usually less invasive and costly and have been recommended in previous pandemics, including influenza.

Mobile phone data provides mobility metrics

In their research article published in Eurosurveillance today, Kamineni et al. compare the impact on mobility when previously non-mandatory interventions to curb COVID-19 transmission were turned into obligatory non-pharmaceutical (NPI) measures. [1]

Based on mobile phone data from the largest Norwegian operator, the authors investigated the effects of interventions that regulated e.g. use of face mask, teleworking, physical distancing, alcohol serving, events, schooling, gyms, restaurants as well as shops and businesses between January 2021 and January 2022. They collected three mobility metrics per day per person for each of the 365 municipalities of Norway: (i) radius of gyration, (ii) time spent away from home and (iii) the maximum distance from home.

The analysis looked at effect of three national interventions in December 2021 that ranged from recommendations to work from home and reduce close contacts beginning of December to regulations of events, banning serving of alcohol after midnight and a face mask requirement in indoor environments about one week later and ultimately making working from home mandatory, banning alcohol serving, imposing digital teaching for universities and a continued face mask requirement as of 15 December 2021. Kamineni et al. investigated the impact of the measures on national level, in the bigger cities Oslo, Stavanger, Tromso, Trondheim and Bergen and in less populated regions of Norway. 

Non-mandatory: less invasive and costly but sufficient
On national level, mobility declined following initial non-mandatory measures – all further measures, including compulsory ones as of mid-December 2021, yielded only comparatively small effects on radius and maximum distance away from home.

Based on their data, the authors found that people in Norway travelled shorter distances from home after non-compulsory measures were introduced. In urban areas, the distance people travelled decreased further when the measures became mandatory. Travelling times also became shorter, and this effect was stronger following the legal mandate than after non-compulsory interventions - in both rural and urban regions.

Stricter metre rules and reopening of gyms, restaurants and shops prompted changes in people’s behaviour.

The authors note that “interestingly, after follow-up mandates, all metrics decreased in urban areas, while only time travelled decreased in rural areas” and that “interventions affected distance and time travelled separately. Nationally, follow-up mandates impacted time more than distance, and these metrics were influenced by different interventions stricter metre rules and reopening of gyms influenced distance, while reopening of restaurants and shops and easing physical distancing affected time.”

Kamineni et al. argue that their findings give valuable insights on the choice of NPI and whether to make them mandatory or not in regional or national settings, making the case that “less invasive and costly non-mandatory measures may be sufficiently effective for rural areas in the case of Norway.”  

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References/notes to editors:
[1] Kamineni Meghana, Engø-Monsen Kenth, Midtbø Jørgen E, Forland Frode, de Blasio Birgitte Freiesleben, Frigessi Arnoldo, Engebretsen Solveig. Effects of non-compulsory and mandatory COVID-19 interventions on travel distance and time away from home, Norway, 2021.
Euro Surveill. 2023;28(17):pii=2200382
Available from: https://doi.org/10.2807/1560-7917.ES.2023.28.17.2200382

In their analysis, Kaminen et al. considered a NPI mandatory, when obligation to follow was based on a regulation or law while non-mandatory recommendations would not lead to any legal consequences in case of non-compliance

Limitations of the study

With the before–after analysis, potential confounders include temperature and weather. While the authors analysed mobility trends before interventions were enacted, there were no controls.