新冠肺炎疫情在美国肆虐之际，回溯疫情发展成为焦点课题之一：新冠病毒是否早已存在并广泛传播？
4月10日，加利福尼亚州圣克拉拉县县长、医生杰夫·史密斯在简报会上表示，新冠肺炎疫情在圣克拉拉县所在的旧金山湾区出现的时间很可能是在去年12月，比当地卫生官员意识到疫情早了几个月。而这一迟滞反应使得新冠病毒一直在大肆传播，直到政府开始实施严格措施。
“新冠病毒一直在我们社区肆意传播，可能已经存在了相当一段时间。”史密斯说。
他还指出，根据美国疾控中心（CDC）、地方卫生部门和其他机构收集的数据，疫情暴发的时间“比我们最初认为的还要早”——很可能追溯到“去年12月”。
A Santa Clara-based physician revealed in a recent briefing that the novel coronavirus had established itself in San Francisco Bay Area months before local health officials were aware of it。 The delayed response to the disease allowed the virus to spread unchecked before strict measures were imposed。
“The virus was freewheeling in our community and probably has been here for quite some time，” Dr Jeff Smith， a physician who is the chief executive of Santa Clara County government， told county leaders Friday。
Data collected by the federal Centers for Disease Control and Prevention， local health departments and others suggest it was “a lot longer than we first believed” – most likely since “back in December，” he added。
至于之前为何没有意识到，史密斯在接受采访时表示，当时美国正处于严重的流感季。“（新冠肺炎）症状非常像流感，如果你是轻症患者，你都意识不到，也不会去看医生。医生或许也不会注意，因为他们也觉得这是流感。”
“当卫生部门（官员）试图追踪疾病源头时……我们无法找到明确的接触者。”史密斯对圣克拉拉县的官员们说：“这意味着病毒已经在社区中传播，而不是像美国疾控中心怀疑的那样，只在中国（传播）或只通过从中国回来的人传播。”
“This wasn‘t recognized because we were having a severe flu season，” Smith said in an interview， according to a Los Angeles Times report。 “Symptoms are very much like the flu。 If you got a mild case of COVID-19， you didn’t really notice。 You didn‘t even go to the doctor。 The doctor maybe didn’t even do it because they presumed it was the flu。”
“When public wellness [officials] attempted to monitor down the start out of the disease … we were not able to come across， exclusively， a call，” Smith advised county supervisors。 “That means the virus is in the local community presently – not， as was suspected by the CDC， as only in China and remaining spread from speak to with China。”
斯坦福大学研究人员在《美国医学会杂志》发布的一项研究报告中写道，他们在1月1日至2月26日期间，对从斯坦福医疗保健中心或附属医院采集的2800名患呼吸系统疾病的病患样本展开研究，发现只有两例感染新冠肺炎。
但负责这项研究的斯坦福大学病理学和传染病学副教授本杰明·平斯基博士表示，患病率如此之低让他感到有点惊讶。
But Jeff‘s remarks on coronavirus slightly contradict a study conducted by researchers at Stanford University who found that the burden of COVID-19 in the Bay Area prior to mid-February was low。
According to the study published on the peer-reviewed The Journal of the American Medical Association， researchers tested 2，888 samples collected from Stanford Health Care or affiliated clinics between January 1 and February 26。
Among those with respiratory symptoms but had tested negative for common respiratory viruses， only two cases were infected with the coronavirus。
“I was a little surprised the prevalence was so low， but it was consistent with what our public health officials in California were observing through normal surveillance methods，” said Benjamin Pinsky， MD， PhD， senior author of the study， associate professor of pathology and of infectious diseases at Stanford University。
据美国媒体报道，旧金山湾区再次发现新冠肺炎患者是在2月27日，当时医生们最终决定给一名已经患病数周的住院女性进行检测。
3月9日，阿赫拉比因新冠肺炎死亡，她是圣克拉拉县首例社区传播的确诊病例。卫生部门的调查人员表示，他们找不到阿赫拉比感染的源头。
据报道，阿赫拉比多数时间都在家中照顾母亲，很少出门，也不怎么接触外人，只是步行去当地一家杂货店购物。不过，阿赫拉比和她母亲居住的社区里，国际居民密度较高。
According to U.S。 media， COVID-19 did not reappear in the Bay Area until February 27， when doctors finally decided to test a hospitalized woman who had been ill for weeks。
The 68-year-old women Azar Ahrabi， who died on March 9， became the region‘s first case of community-spread coronavirus。
Health investigators said they could find no source of Ahrabi‘s infection。 She was reported to barely have exposure to other people， and most of time， she stayed at home and took care of her mother， except when walking to a local grocery store。 But she did live in a neighborhood with a high density of international residents。
聚焦新型冠状病毒肺炎疫情 全球多国爆发新冠肺炎疫情 美国成疫情“震中”