Social distancing may be needed in US, on and off, till 2022: Study
WASHINGTON: A one-time lockdown will not halt the new coronavirus and repeated periods of social distancing may be required into 2022 to prevent hospitals from being overwhelmed, Harvard scientists who modelled the pandemic's trajectory said on Tuesday.
The team's computer simulation, published in a paper in the journal Science, assumed Covid-19 will become seasonal, like closely related coronaviruses that cause the common cold, with higher transmission rates in colder months.
But much remains unknown, including the level of immunity acquired by previous infection and how long it lasts, the authors said.
"We found one-time social distancing measures are likely to be insufficient to maintain the incidence within the limits of critical care capacity in the US," lead author Stephen Kissler said in a call with reporters.
"What seems to be necessary in the absence of other sorts of treatments are intermittent social distancing periods."
Widespread viral testing would be required to determine when the thresholds to re-trigger distancing are crossed.
The duration and intensity of lockdowns can be relaxed as treatments and vaccines become available. But in their absence, on and then off distancing would give hospitals time to increase critical care capacity to cater for the surge in cases.
"By permitting periods of transmission that reach higher prevalence than otherwise would be possible, they allow an accelerated acquisition of herd immunity," said co-author Marc Lipsitch.
Conversely, social distancing without respite can be a bad thing. Under one modelled scenario, "the social distancing was so effective that virtually no population immunity is built", the paper said, hence the need for an intermittent approach. - AFP