With Covid-19 cases still rising a week into the third lockdown (and after several weeks of Tier 3 restrictions in London and the South East) the questions are inevitably being asked: why isn’t lockdown reducing transmission of the virus and do we need even more stringent rules, whatever they might be? While some studies claim to have quantified a beneficial effect from lockdown measures during the first wave of Covid-19, a study at Stanford University questions this.
Dr Eran Bendavid and Professor John Ioannidis studied the imposition of ‘non-pharmaceutical interventions’ (NPIs) in ten countries and have reached the conclusion that while less-restrictive NPIs (which include social distancing and appeals to the public to reduce their social activities) had a clear effect, more-restrictive NPIs (which include business closures and stay at home orders) produced no clear additional benefits.
Their paper, published in the European Journal of Clinical Observation, argues that previous studies on NPIs tended to assume that all beneficial effects were the result of the last measures that happen to have been imposed (i.e. the most severe measures), or failed to take into account the dynamic nature of an epidemic curve, assuming that the epidemic would have continued growing at the same rate it was rising before the measures were imposed. The Stanford team compares the experience of England, France, Germany, Iran, Spain, Italy, the Netherlands and the US — all of which imposed more restrictive NPIs — with the counterfactuals of Sweden and South Korea, which did not.
Their conclusion? That all the apparent benefits were derived from less-restrictive NPIs and from changes in public behaviour following the imposition of the lighter restrictions. Ordering businesses to close and telling people to stay at home did not appear to reduce rates of infection further. They write:
“While small benefits cannot be excluded we do not find significant benefits on case growth of more restrictive NPIs. Similar reductions in case growth may be achievable with less restrictive interventions… We do not question the role of all public health interventions, or of co-ordinated communications about the epidemic, but we fail to find an additional benefit of stay at home orders and business closures.
It is never going to be easy to establish exactly which measures worked well and which did not — no one can conduct a controlled experiment where two identical countries are subjected to different Covid-19 measures. Moreover, there have been other studies that have claimed that full lockdowns have helped to reduce infection rates. But as the Stanford study shows, there is more than one side to the debate.