This more recent Thai study shows that natural immunity is far superior for all known variants... https://www.news-medical.net/news/20210719/Thai-study-looks-...
CoronaVac vaccine? This is a much less effective vaccine than Pfizer and Moderna ( https://en.wikipedia.org/wiki/CoronaVac ), so it's not surprising that natural immunity would be superior.
It found that double pfizer jabbed people were 13 times more likely to be infected than those who had already recovered.