The title corresponds to the idea of the whole text. The aim is clearly stated and the abstract generalises the aim, methods and the findings of the study. The references used are recent and appropriate.

The background presents in brief what is already known about the HEV seroprevalence among the Chinese people. However, the introduction focuses on the lack of information about the HEV seroprevalence among different ethnic groups. In view of this, the authors' aim is innovative as such results would elucidate the seroprevalence among these groups and the potential risk factors for HEV infection.

The methods used are thoroughly described- including the sampling process and the statistic tests. The latter are sound enough to guarantee the results validity and reliability. The limitations of the analysis are also discussed.

Results are given in appropriate figures and tables with all the needed legends, which aid the readers in better understanding of the findings.

The discussion is a short comment on the results. The findings are compared with relevant results that have already been published. Moreover, the authors hypothesise the possible risk factors, giving evidence of them, based on their study.

Conclusion generalises in short the whole investigation.

Some sentences are ambiguous, for example: page 5, paragraph 1, line 7: "However, there is to date no evidence-based explanation on the sex disparity to HEV susceptibility, requiring further investigation"

There are some typos, as well- for instance- page 4, paragraph 2, line 4 "mmajority"

The study answers the aim and give useful information about the HEV seroprevalence among different ethnic groups in China.