Lockdowns could be replaced by targeted measures with a much smaller economic impact, such as banning mass events

See Superspreader Events Offer a Clue on Curbing Coronavirus by Bojan Pancevski of The WSJ. Excerpts: 

"SARS, another coronavirus that originated in China and is genetically near-identical to Covid-19, briefly spread world-wide in 2003 after a guest at the Metropole Hotel in Hong Kong infected international visitors who then spread the disease across continents, said Michael Small, a lecturer in applied mathematics at the University of Western Australia.

Prof. Small, who holds the chair in complex engineering systems at CSIRO, the country’s national science agency, studied both coronavirus outbreaks and said the lesson is that authorities must curb all gatherings of more than 100 people.

“This could well be the end of the open-plan office,” he said. “You can see it clearly from the data in many, many places: superspreading events cause bursts of infection that fuel exponential growth, but that can very quickly be reduced to linear growth if you limit the mass gathering of people.”

His modeling, for Australian consulting company Integrated Energy, shows that lockdowns could be replaced by targeted measures with a much smaller economic impact, such as banning mass events, asking a significant number of white-collar workers to work from home and encouraging widespread use of smartphone contact-tracing apps.

What about crowded subways and commuter trains? Prof. Small is confident that the use of subways during rush-hour is certain to turn into a super-spreading event.

When London authorities reduced the number of subway trains in March—causing greater crowding than usual—they created superspreading conditions, said Prof. Michael Levitt, a Stanford lecturer and Nobel Prize laureate. He advocates the use of face masks and regular testing of bus drivers, shopkeepers and delivery couriers. Bars should also be regulated, he said, because loud music there forces patrons to speak louder.

In Britain, which has one of the worst Covid-19 death rates in the world, authorities allowed for a series of mass events to take place in March, including large-scale concerts, soccer games and horse races. George Batchelor, director of Edge Health, a data-analytics firm that works with Britain’s health-care provider, thinks those gatherings prompted a significant increase in hospitalizations and mortality related to Covid-19 in the respective regions. He studied two soccer matches and a horse race—all of which took place outdoors, preceded and followed by the mass use of public transport and visits to bars and pubs."

"A study published this week found that banning mass gatherings had the biggest contribution to bringing the epidemic under control in Germany."