If lockdowns were effective why didn't we see spikes after VE Day/when people flocked to beaches/anti-racist protests/when the pubs and restaurants re-opened?
Because the spike takes time, multiple generations of transmission are required to really ramp up the numbers before we end up at the catastrophic level of infection seen in the first wave. This is especially true when the lockdown measures up to that point reduced number of infections at any one moment to low levels. Meaning any resurgence that came from relaxations was starting from a fairly low base and would take considerably time to develop.
Just the same as how the virus got going in the first place really, it was starting from a low number and took weeks to develop. And after behaviours started to massively change and then a week later we locked down, we still had to deal with all the infection out there at that point and the fact transmission would not instantly vanish. But it took quite some time to reach that point, and so it will be true again this time, a repeat that should be at a different pace because R now shouldnt be as bad as R was before the first behavioural changes kicked in.
Sweden has many differences to the UK. Its a bit of a red herring, as the virus resurgence in the UK we are now experiencing demonstrates.
Sticking to what actually happened in the UK, the first wave curve is a reasonable fit for lockdown having a big impact. After all, the following is how I would describe events:
Cases were repeatedly introduced to the UK over a period of several months.
Community transmission got going and at some fairly late stage it became clear how rapidly the number of cases including serious cases were increasing.
Very little of the data shows the full picture, but its still consistent with the timetable of measures.
Behaviours started changing.
About a week later we had a more comprehensive lockdown.
Sure enough, number of deaths, hospitalisations etc peaked a few weeks later.
All measures for number of infections, serious cases and daily deaths then started to fall.
The rate of decrease slowed as various relaxations kicked in.
Levels trundled along the bottom for a bit, as fresh increases in a few areas were mostly offset by continuing decreases elsewhere.
The tipping point came and the numbers started to go back up again.
Its exactly the classic pattern we would expect from doing too little, then doing a lot, then gradually relaxing until we get past the tipping point, and then having to respond again in a timely manner to keep the numbers down.
People that have convinced themselves that lockdown has done nothing rarely present a hypothesis for why they think all the massive, life-altering change in behaviours did nothing. It is entirely insufficient to just cling to the idea that the virus would have peaked and then diminished at that time even without lockdown. Too bloody convenient. I have explored the theory and, like most theories, cannot discount it 100%, I cannot prove 100% that lockdown was responsible for everything, but lockdown being responsible is still by far the most likely possibility. And we've seen the pattern in so many countries, and even Sweden did things that changed behaviours and the viruses ability to spread.
Some people who bought into the 'it would have gone away then anyway' theory were sensible enough to change their tune once they saw the clear signs from Madrid, a region that was badly affected in the first wave, suffering from the virus once more, with notable leaps in hospital admissions. In summer, nowhere close to fitting the timing of the standard seasonal trends you refer to. And that reality snaps off some of the branches they were clinging to, the alternative explanations for why the virus diminished in numbers the first time.
