On a related note, officials in Hong Kong has been talking about locking down the city and making everyone take PCR tests since the latest outbreak. The original plan is to lock down in late March. That was postponed presumably due to pushes from the industry. The official reason is, laughably, an inadequate number of quarantine spaces.
I think the Shanghai lockdown is to show Hong Kong that how to lock down a megapolis relatively cleanly. Dividing the city into two halves and locking down each half for 5 days. End up extending the lockdown due to every district in Shanghai has confirmed cases. Can't say it went well.
If I’m not mistaken, the expected outcome is that there would still be some cases but drastically reduced numbers compared to a full blown outbreak from doing little or nothing.
With the highly infectious variant, a complete lockdown will certainly slow transmission, but you won't be able to drive it to zero cases unless you're willing to lock down the city for months.
Their goal is to isolate people until nobody is infectious, but since they aren't doing it individually, but typically by household, you can't just isolate for 2 weeks and be done. If one person is infected, they might transmit it to someone else before recovery, then that person gives it to another person before recovering. Start sequentially stacking the 2-3 week isolations and in a crowded household you might need to wait for 4-6 isolation cycles (2-3 months?) before there are no more new infections.
And that ignores the essential workers like healthcare, sanitation, food transportation, preparation, delivery. All it take is 1 infected person to start all over again.
Zero covid is just not practical once an outbreak gets beyond a very small cluster. But that won't stop China from trying.
I think the Shanghai lockdown is to show Hong Kong that how to lock down a megapolis relatively cleanly. Dividing the city into two halves and locking down each half for 5 days. End up extending the lockdown due to every district in Shanghai has confirmed cases. Can't say it went well.