The second wave, and maybe even the third and fourth, we will definitely get later. This infection will return to us several times a year. In the meantime, the reality is that the last person who had a coronavirus was discharged in China today.
I have no idea from where you are getting these information, the last person who was corona positive is discharged means that there are no more patients in China, yet they are publishing how many patients they are identifying every day and yesterday there was 12 patients and today they identified 11 patients and going by that numbers there is no way it was the last patient 
.And most probably the number of cases will continue to increased in this second wave. South Korea as well experienced the second surge and here in our country, second wave of cases are popping. Even those who was positive and cure became positive as well, which obviously remains a mystery for now and we have so much to learn from this virus. In the meantime, even if the quarantine has been lifted in other countries, I will still be cautious at this point though. Really hard to fight an invisible enemy.
There is no assurance because there is no vaccine yet, I hope people will still understand that there's still a high risk, not because the quarantine is lifted, people will already assume that they are already safe, sometimes the lack of education will cause them trouble.