@BigChocFrenzy yes. The trade war between China and the US is a huge factor in Trump's responses. If we go back some decades, trade wars go way back. China began to own the means of production to serve global requirements. The US deals in imports and China in exports. One can fully understand where conspiracy theories emerge given the trade war.
That said, the OP, has asked a very relevant question.
At the risk of sounding a conspiracy theorist, the UK haven't just happened on this, they've known about this for months.
The UK dont have to look to other countries for models of suppression or mitigation. Boris has been described as a 'wannabe' Churchill. Churchill was a fantastic wartime leader, as a peacetime leader, not as good. Boris has come into his own.
UK only need to look back at the foot and mouth epidemic, the fuel strike. Tell the Brirish not to panic buy, they'll panic buy. Foot and mouth crisis was a war between farmers and dog walkers. (Huh, ringing any bells?)
Instead of wondering why the borders weren't closed, perhaps a look into how democracy works. It begins to lose what it stands for. Communism and Capitalism always run hand in hand. Both eat themselves from within.