Coronavirus: Lockdowns reduce infections but not deaths, US study concludes

Shutdown measures to curb the spread of COVID-19 are effective in reducing the number of infections but not deaths.

Shutdown measures to curb the spread of the coronavirus are effective in reducing the number of infections but not deaths, ­according to the first comprehensive analysis of stage three and stage four shutdowns worldwide.

Released by the US National Bureau of Economic Research, the study compared the infection and mortality impact of different responses of 50 US states, and found lockdowns lowered infections by 44 per cent after three weeks.

“That corresponds to approximately 2510 fewer cumulative COVID-19 cases for the average state (that adopted a lockdown),” the four authors concluded. They could find no reliable relationship between lockdowns and subsequent deaths from the virus.

The US case fatality rate from COVID-19 of 5.4 per cent suggests about 135 lives might have been saved in the average state. After California locked down on March 19, 39 other US states issued stay-at-home orders.

On Friday, our national cabinet is expected to announce a phased relaxation of lockdowns across Australia, which has a population smaller than Texas, that have been in place almost six weeks.

The US death toll from the virus, where deaths per 100,000 range from 126 in New York to six and three in Texas and Florida respectively, is approaching 80,000,

The analysis, by economists at the universities of San Diego and Colorado, also found a steady decline after one week in an initial jump in the share of households that were complying with lockdowns, which it attributed to “cabin fever, a belief that one week was enough time (for it) to have worked, or diminishing marginal utility of family time”.

In Australia, infections increased from 4763 to 6645 over the first three weeks of lockdown.

Peter Swan, a professor of economics at UNSW, said the study was “excellent” but “may exaggerate” the benefits from lockdown locally.

“A very sizeable proportion of all cases here came from failure of border protection (such as) Ruby Princess. Since we are an ­island with lower population density and we closed our borders much earlier, any short-run public health benefits from lockdown are likely to be far less,” he said.

The analysis, based on US data from March 8 to April 20, was controlled for weather and whether states had interstate travel bans.

The authors said the “larger ­efficacy” of lockdowns might be less effective if a vaccine was a remote prospect or if the eco­nomic costs of shutdowns were significant.