STA, 14 January 2020 - A ban on travel between municipalities has not reduced people's mobility, which makes its efficacy questionable, shows a study that analysed mobility and contact tracing during epidemic waves. Mobility is a major factor in the epidemic's development, researchers said, adding that the current situation was mostly a result of belated measures.
The study, conducted by the Institute for Biostatistics and Medical Informatics of the Ljubljana Faculty of Medicine, focused on mobility in the first and second epidemic waves to establish why the epidemiological situation was so strikingly different in the autumn compared to the spring.
Major changes in population mobility coincide with the timeline of adopting certain measures, such as restricting gatherings, declaring epidemic, closing schools, suspending public transportation and closing bars, restaurant and hotels, the study shows.
During both waves, movement in residential neighbourhoods increased, whereas there has been a downward trend regarding movement in workplaces or other venues.
The biggest drop was recorded in the spring when workplace mobility was halved and movement caused by other activities dropped by 60%, coinciding with the adoption of Covid measures.
In November, workplace mobility decreased by 30% and movement prompted by other errands by 50%. Such mobility was down also during summer months but it reached pre-Covid levels in September.
The institute drew up three scenarios of possible epidemic developments, taking into account various mobility levels from March through November and deeming neighbourhood mobility less key than other movements.
If Slovenians had been as mobile in early November as they were in the spring, there would have been up to 30% reduction in the death toll until early December.
The researchers also note that the second lockdown began too late since the theoretical possibility of a death toll that would be lower by more than 30% was not realisable any more due to the rapid coronavirus spread.
If the lockdown, which was imposed on 26 October, had already started in mid-September and would trigger the same response regarding mobility levels, the number of deaths could have been reduced up to 80%, meaning some 1,000 deaths fewer between March and December.
If mobility restrictions had been imposed at the start of October, the death toll could have still been reduced by 80%, however the measures would have to be stricter, at least as strict as during the first wave.
The institute also prepared a model of what the situation would have looked like if contact tracing and quarantine measures had been consistently effective throughout the epidemic.
Taking into account the actual timeline of imposing measures and their efficacy, the mortality rate would have then been reduced by 75%, the researchers said, noting that the figure was hypothetical as contact tracing is unlikely to be equally effective amid such high case numbers.
"The current epidemiological situation is thus mostly a result of belated and disproportionate measures in the autumn. Hence, the growing number of new cases reached such a level that the spread of the epidemic no longer allowed active contact tracing."
If contact tracing and quarantine regime had remained operational, 15%-20% reduction in mobility compared to pre-Covid levels would have been enough to contain the epidemic, the institute said.
"Oscillating between extreme measures and complete relaxations could be replaced by somewhat more moderate but constant contact restrictions and active contact tracing. The goal should be to come up with measures that reach an appropriate level of restrictions in a sustainable way."
