Banning public events may lower COVID-19 (R) breeding number – a key measure of virus transmission – by 24% in less than a month, according to modeling study published in The Lancet journal .
An R value greater than 1 indicates an increasing epidemic, while an R value less than 1 indicates a decreasing epidemic.
Research using data from 131 countries suggests that individual measures, including closing schools and workplaces, banning public events and gatherings of more than ten people, requiring you to stay at home, and limitations of internal movement, are associated with reduced transmission of SARS-CoV-2.
However, the combined measures are more effective at reducing transmission, the researchers said.
“We have found that the combination of different measures has shown the greatest effect in reducing the transmission of COVID-19. As we see a resurgence of the virus, policymakers will need to consider combinations of measures to reduce the R number “said Professor Harish Nair of the University of Edinburgh, UK.
“Our study can inform decisions about which measures to introduce or lift, and when to expect to see their effects, but it will also depend on the local context – the R number at any given time, the capacity for healthcare. and the and the economic impact of the measures, ”said Mr. Nair.
Looking at the measures individually, a ban on public events was associated with the greatest reduction in R – 24% reduction after 28 days – which the researchers may be suggesting because they are likely to prevent super events. spreader and it was often the case. the first measure to be introduced in countries.
The measures most strongly associated with an increase in R were the lifting of bans on gatherings of more than ten people and the reopening of schools, the researchers said.
Although the reopening of schools was associated with a 24% increase in R on the 28th day, the researchers warn that they have not been able to account for the various precautions taken by some countries for the reopening of schools, eg limitation of class size, distance measurement, routine deep cleaning, personal hand washing, face masks and thermal temperature checks on arrival.
They said these are essential for a safer reopening of schools and should be taken into account when interpreting this result.
“We saw an increase in R after schools reopened, but we don’t know if the increase is attributable to specific age groups, where there may be substantial differences in adherence to social distancing measures at inside and outside classrooms, ”added Mr. Nair.
“In addition, more data is needed to understand the specific role of schools in increasing the transmission of SARS-CoV-2 through robust contact tracing,” he said.
The study, however, does not take into account other potentially influential factors that impact R – including, but not limited to, adherence to interventions, changes in population behavior, subnational differences in R, or effects contact tracing. and isolation – all of which vary by context.
Using the R number as an indicator of transmission also has limitations, as it is difficult to accurately estimate, especially when the prevalence is low, the researchers said.
In this modeling study, data on daily country-level estimates of R were linked to data on measures that these countries had in place from January 1, 2020 to July 20, 2020.
Each country’s timeline has been divided into individual phases when all measurements have remained the same in that country.
The analysis included 790 phases from 131 countries and the authors used a model to measure the association between the measures in place and changes in R.