Locking the city down like they did last time won't stop anything, it would logically slow it down. Even if you somehow got people to stop doing illegal gatherings.. The reason it won't work is you are still allowing people in the country and your "locked-down" city. The only way a lockdown will actually work is if no "in or out" of the city, no matter what.. No flights, baracade the highways and roads into the city, etc.. Otherwise the spread will easily start again.
With long term health facilities which should have the highest precautions in place still having breakouts, it leads me the think obviously our measures aren't working and something needs to be re-evaluated. Because if we can't protect even the buildings with the most at risk how can we protect the rest of the city?