Case numbers do not always decline after lockdowns

Lockdown proponents often argue that, although case numbers sometimes decline in the absence of a lockdown (as in Sweden, South Dakota, Florida), case numbers always decline in the presence of one. Once you put a lockdown in place, they claim, the curve reaches its peak and the epidemic starts to retreat.

There are certainly many countries where a decline in case numbers has coincided with the imposition of a lockdown. However, this doesn't necessarily mean that one caused the other.

As the researcher Philippe Lemoine has argued, people start changing their behaviour voluntarily when they see deaths and hospitalisations rising. The government, meanwhile, feels an increasing need to "do something", and the subsequent imposition of a lockdown happens to coincide with the peak of the infection curve.

Consistent with this account, there are several countries where a lockdown was imposed, but case numbers did not immediately decline; or if they did decline, they rose again while the lockdown was still in place. These examples constitute evidence against the claim that lockdowns have a substantial effect on the epidemic's trajectory. Here I will present six.

It's important to note that some countries went into lockdown all at once, whereas others built up restrictions gradually over several weeks. This raises the question of exactly how to define a lockdown. For the purpose of this analysis, I will rely on the Oxford Blavatnik School's COVID-19 Government Response Tracker.

The dataset includes several measures of government restrictions. Each one is accompanied by a "flag" indicating whether the relevant restriction was applied to specific regions or the entire country. I will define the start of a lockdown as the first day on which there were mandatory workplace closures and a mandatory stay-at-home order in place for the entire country.

The first example is Israel, which went into lockdown on December 27th, but did not see the peak of its infection curve until January 17th.

The second example is Lebanon, which went into lockdown on November 14th, but did not see the peak of the curve until January 16th.

The third example is Slovakia, which went into lockdown on October 22nd, but did not see the peak of the curve until January 6th.

The fourth example is Slovenia, which went into lockdown on October 20th, but did not see the peak of the curve until January 10th.

The fifth example is Peru, which went into lockdown on March 16th, but did not see the peak of the curve until June 2nd.

The sixth example is Venezuela, which went into lockdown on September 28th, but did not see the peak of the curve until April 6th.

Note that, in every case, the lockdown measures were in place until after the peak of the curve. The fact that cases did not immediately decline, or proceeded to rise again (as in Venezuela), cannot therefore be blamed on the lifting of lockdown measures.

The evidence presented here is consistent with the many empirical studies finding that lockdowns do not substantially reduce deaths from COVID-19.