EU is looking into the possible side effects of mRNA vaccines in relation to the inflammation of the heart and kidney problems but still stressing benefits outweigh the risk.
That may be the case for Europe but for China with its almost nonexistent cases of infection, inactivated vaccines, possibly working with booster shots as appropriate, are probably the better choice over the mRNA vaccines.
In the comment section, one chap mentions about 2 vaccinated youngsters (in Singapore) having come down with serious heart inflammation/heart attack with one of them ending up dead. In China's case with its huge population, that number of people could be amplified like 1400/5 times had the country been using mRNA vaccines.