A complete and accurate statistical panorama and analysis of cases contracted with the
SARS-CoV-2 Omicron BA.2 subvariant are given under the conditions of strict mandatory
quarantine and isolation and of a high rate of full vaccination. Sars-Cov-2 is still new, and little is
known about either its direction of variation or its propagation laws. No country other than China
has been able to disclose every infected case and to have the data of heavily intervening large
outbreaks. Here, my study reveals that the BA.2 subvariant can still spread very fast and wide in
areas with strict “dynamic zero-COVID strategy”i in China, that there exist in different cities as
many as twenty-time large differences in morbidity rate unrelated to any of the influence factors
known and that the Omicron BA.2 subvariant is unpredictable of its virulence, although its severe
rate of confirmed cases is low. This analysis provides first-hand solitary and valuable information
for further research on similar epidemics in the future. It may bring new thoughts for correction
of present epidemiological theory and mathematical models. It may also give other countries
time to be better prepared for the coming 6th wave driven by Omicron BA.2.