一名新冠肺炎康复者自欧洲返回香港后，其新冠病毒检测结果再次呈阳性。香港大学微生物学系团队证实，该患者是第二次感染新冠病毒，属全球首例。

Hong Kong scientists are reporting the case of a healthy man in his 30s who became reinfected with coronavirus four and a half months after his first bout.

香港科学家报告说，一名30多岁的健康男子在首次感染新冠病毒四个半月后第二次感染。

bout [baʊt]：n.回合；发作

They say genome sequencing shows the two strains of the virus are "clearly different", making it the world's first proven case of reinfection.

科学家表示，基因组测序显示，两次感染病毒的毒株“明显不同”，使之成为全球首例被证实的二次感染病例。

The World Health Organization warns it is important not to jump to conclusions based on the case of one patient.

世界卫生组织警告说，目前重要的是，不要根据某一个病人的情况就贸然下结论。

jump to conclusions：过早下结论

And experts say reinfections may be rare and not necessarily serious.

专家说，二次感染可能很罕见，而且不一定很严重。

There have been more than 23 million cases of coronavirus infection around the world.

目前，全球新冠肺炎确诊病例达到2300多万例。

Those infected develop an immune response as their bodies fight off the virus which helps to protect them against it returning.

当身体对抗病毒时，受感染者会产生一种免疫反应，这种反应有助于保护他们免受二次感染。

The strongest immune response has been found in the most seriously ill patients.

在病情最严重的病人身上发现了最强的免疫反应。

But it is still not clear how strong this protection or immunity is - or how long it lasts.

但目前还不清楚这种保护或免疫力有多强，也不清楚它能持续多久。

 A medical worker tests novel coronavirus samples at a lab in Beijing, on June 26, 2020. [Photo/Xinhua]

And the World Health Organization said larger studies over time of people who had previously had coronavirus were needed to find out more.

此外，世界卫生组织表示，还需要对曾感染新冠病毒的人进行更长时间以及更大规模的研究，以发现更多信息。

This report, by the University of Hong Kong, due to be published in Clinical Infectious Diseases, says the man spent 14 days in hospital before recovering from the virus but then, despite having no further symptoms, tested positive for the virus a second time, following a saliva test during airport screening.

香港大学将把报告发表在《临床传染病》期刊上。报告称，这位男子此前住院14天才从病毒感染中康复。此次该男子没有任何症状，但在机场检测时进行唾液测试，病毒检测再次呈阳性。

"This is a very rare example of reinfection," said Brendan Wren, professor of microbial pathogenesis, at London School of Hygiene and Tropical Medicine.

伦敦卫生和热带医学院的微生物发病机理教授布伦丹·雷恩说：“这是二次感染的一个非常罕见的例子。”

"And it should not negate the global drive to develop Covid-19 vaccines.

“这也不应否定全球研发新冠疫苗的努力。”

"It is to be expected that the virus will naturally mutate over time."

“可以预料，随着时间的推移，病毒会自然变异。

Dr Jeffrey Barrett, senior scientific consultant for the Covid-19 genome project at the Wellcome Sanger Institute, said: "Given the number of global infections to date, seeing one case of reinfection is not that surprising even if it is a very rare occurrence.

威康桑格研究所新冠病毒基因组项目高级科学顾问杰弗里·巴雷特博士说：“考虑到迄今全球感染病例的数量，看到一例二次感染并不那么令人惊讶，尽管这种情况非常罕见。”

"It may be that second infections, when they do occur, are not serious - though we don't know whether this person was infectious during their second episode."

他说：“可能第二次感染发生时并不严重，不过我们不知道这个人在第二次感染时是否具有传染性。

Prof Paul Hunter, from the University of East Anglia, said more information about this and other cases of reinfection was needed "before we can really understand the implications".

东安格利亚大学的保罗·亨特教授说，“在我们真正理解其影响之前”，需要更多关于这个病例和其他二次感染病例的信息。