Not really. With one proviso: if you locked down every person in the land, inside their houses, for six months or more, you'd reduce the spread of any virus to about zero. So there's that. Just as you'd reduce road deaths to zero if you prohibited people from driving cars at all.
But that's not the situation we have. What we have is a hotchpotch of measures around the world, commonly known as "lockdowns", but aka "Non Pharmaceutical Interventions" or NPIs. And given that none of these is absolute, we have a range, and what we would expect is that the more stringent the NPIs, the fewer Covid deaths we would have.
"Correlation does not (necessarily) mean causation". But the opposite is true. If there is a causation, then we will have a correlation. That is if A and B are related by high correlation, it does not mean that A caused B (though maybe it did...). But if we hypothesise that A caused B, then when we get data it should show a significant correlation, or else we must question the hypothesis.
With Lockdowns and per capita Covid deaths from the hypothesis is this: Lockdowns => fewer infections => fewer deaths.
Or, more simply Lockdowns => fewer deaths. Or A => B. And the more of A the less of B. There should be a negative correlation. The more of one the less of the other.
Is that what the data show? The answer is NO.
Again: the hypothesis is the greater the lockdown stringency the fewer the deaths per capita. That is, in the figure above, the red line is what the hypothesis predicts. Higher stringency of lockdown on the Y axis, fewer deaths on the X axis. We expect a negative correlation of >= -0.7.
In fact it is positive: +0.55. [my original work here]
So we see the opposite of our hypothesis: to the extent that there is a trend (it's weak, sure) it's going the opposite direction: the greater the stringency the higher the number of deaths per capita.
This might mean: (A): greater lockdowns lead to more deaths or (B) more deaths lead to greater lockdowns. Being charitable, we can dismiss (A) on common-sense grounds; how can tighter lockdowns lead to more deaths? I'm willing to dismiss it, even if there are some grounds for thinking that perhaps lockdowns actually lead to excess deaths. But still, let's leave that aside for now. Which leaves (B): the figures we see for tight lockdowns correlated with higher deaths rates is because the tighter lockdowns are reacting to the deaths.
An objection might be that tight lockdowns in the past have already led to reduction in death rates, thus lower stringency is now also correlated with lower deaths per capita. But that's not what the figures show going right back to the major waves last year when I did a similar analysis. At no time do the figures show that lockdowns have led to subsequent reduction in death rates, except when that was happening anyway, as appears to be part of natural up and down curves across the planet. Or, in the case of the UK, when the vaccine program began to bite. [ADDED: ew Zealand is an exception, with strict border control early in and now low lockdown stringency. But, New Zealand ?!…. One can look at individual countries on the Oxford tracker since the beginning of the pandemic and find, for nearly all, no correlation between the strictness of lockdown and the death rates]
The US is a perfect illustration of the failure of strict lockdowns to correlate with lower death rates. 50 states, many the size of substantial countries. Decisions about how to handle the pandemic are taken by governors of those states. Not by the president of the United States. By governors and by their city mayors. Roughly half US states are run by Republican governors and half by Democratic. They took very different approaches. I have pointed out -- with the data -- several times, that of the top ten worst performing states in terms of deaths per capita (which I reckon is the only reasonably comparable figure), the top eight are Democrat-run states, with high stringency of lockdown.
This fact was completely ignored by the US media, who instead lionised the efforts of NY governor Andrew Cuomo -- whose state in fact was by far the worst in the US, indeed the worst per capita in the world -- while excoriating the state of Florida, run by Republican governor Ron deSantis, when Florida has in fact done very well. And there's no need to put a "but" when discussing its success. [BTW, it's only just now that the MSM is catching up with the fact that Cuomo is not quite the Covid Superman they all claimed he was, plus being a serial sexual predator-- remember when his brother on CNN, Chris Cuomo, called him the LuvGov, not quite anticipating that he'd be rather too much Luv and too little Guv. National Review has been on it all along].
ADDED: Then there's the case of North and South Dakota, one of which had a mask mandate and the other which didn't. Results, very similar. Some thoughts on the Dakotas here.
There are many PhDs to be examined, many books and studies to be written about this pandemic. One must surely be to study the extent of disinformation and extreme partisanship when made people taste chalk as cheese and use cheese to write on the white/blackboard.
Meantime: don’t call people who question the efficacy of lockdowns “Covid deniers”! Just don’t.