In a new study, researchers found that an alternating cycle of 50 days of strict lockdown followed by 30 days of easing could be an effective strategy for reducing the number of COVID-19-related deaths and admissions to intensive care units.
The research was conducted by an international team of scientists.
The coronavirus pandemic has imposed an unprecedented challenge on global healthcare systems, societies, and governments.
The virus SARS-CoV-2, which causes COVID-19 disease, has been detected in every country, with more than 5 million confirmed cases and a death toll of more than 320,000 worldwide to date.
There are currently no effective treatments for the disease and a widely-available vaccine is likely to be at least a year away.
The principal strategy to control the disease globally has focused on measures that minimize person-to-person transmission of SARS-CoV-2 through social distancing; including isolating suspected infected individuals, shielding vulnerable groups, school closures, and lockdowns.
While such measures are effective at slowing disease spread and preventing health systems from becoming overwhelmed, these measures can also lead to significant job losses, financial insecurity, and social disruption.
As such, there is a growing concern that these interventions may be unsustainable over the long term.
An alternative approach may be to alternate stricter measures with intervals of relaxed social distancing (with measures of effective “test-contact trace-isolate” and shielding of the vulnerable kept in place).
However, it is unclear what the frequency and duration of such dynamic interventions should be and which strategy could be adapted globally across countries with diverse health and economic infrastructures.
To address these uncertainties, an international team of researchers from the Global Dynamic Interventions Strategies for COVID-19 Collaborative Group modeled three scenarios across sixteen countries, from Belgium to India, that vary in setting and income.
They were interested in the difference in impact between strategies aimed at mitigation and those aimed at suppression.
Mitigation measures reduce the number of new infections, but at a relatively slow rate.
On the other hand, suppression measures lead to a faster reduction in the number of new infections by applying additional interventions such as strict physical distancing, including lockdown.
They found the scenario involved a rolling cycle of stricter, 50-day suppression measures followed by a 30-day relaxing, would reduce the R number to 0.5, and keep ICU demand within national capacity in all countries.
Since more individuals remain susceptible at the end of each cycle of suppression and relaxation, such an approach would result in a longer pandemic, lasting beyond 18 months in all countries.
However, a much smaller number of people—just over 130,000 across the 16 countries modeled—would die during that period.
In comparison, the team found that after a continuous, three-month strategy of strict suppression measures, most countries would reduce new cases to near zero.
Looser, mitigation strategies would require approximately 6.5 months to reach the same point.
However, such prolonged lockdowns would be unsustainable in most countries due to potential knock-on impacts on economy and livelihood.
The team says that dynamic cycles of 50-day suppression followed by a 30-day relaxation are effective at lowering the number of deaths strongly for all countries throughout the 18-month period.
The specific durations of these interventions would need to be defined by specific countries according to their needs and local facilities.
The key is to identify a pattern that allows countries to protect the health of the population not only from COVID-19 but also from economic hardship and mental health issues.
The study is published in the European Journal of Epidemiology.
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