My friend said he was going to get the third dose of COVID-19 vaccine. What's wrong with this vaccine?

Kangxinuo COVID-19 vaccine is a previous injection, which can activate the immune effect only once, and it belongs to the third generation vaccine technology. At present, Kangxinuo COVID-19 vaccine is one of two kinds of vaccines that are strengthened in turn, which can enhance the immune effect of the vaccine. Especially for Omicron virus. According to the news, the COVID-19 vaccine produced by sequential booster injection is six times that of homologous booster injection. At present, Omicrovirus has become one of the major COVID-19 in China. So, under the current situation, it is really better to strengthen KanginoCOVID- 19 vaccine in order?