A/Prof Kenneth Mak的原话是
There is a significant risk of vaccine breakthrough with the Sinovac vaccine.

其实这种breakthrough在新加坡前不久就已经发生过了，就是樟宜机场的case
参阅straitstimes的文章
https://www.straitstimes.com/singapore/health/sciencetalk-vaccination-is-key-to-singapores-fight-against-covid-19

Asymptomatic or mild symptoms for breakthrough infections
Like many other vaccines that are currently in use, the mRNA Covid-19 vaccines are not 100 per cent effective.
However, it is noteworthy that many of these breakthrough infections were picked up as a result of routine swabbing, and not because these individuals were ill.

雅虎的这篇文章把标题写成significant problems有博眼球之嫌