Background: On 30 January 2020, COVID-19 was declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization. Almost a month later, on 29 February 2020, the first case in New York City (NYC) was diagnosed.
Methods: Three hundred sixty persons with COVID-19-like illness were reported to the NYC Department of Health and Mental Hygiene (DOHMH) before 29 February, but 37 of these tested negative and 237 were never tested for severe acute respiratory syndrome coronavirus 2. Records of 86 persons with confirmed COVID-19 and reported symptom onset prior to 29 February 2020 were reviewed by 4 physician-epidemiologists. Case-patients were classified as possible delayed recognition (PDR) of COVID-19 when upon medical review the reported onset date was believed to reflect the initial symptoms of COVID-19, or insufficient evidence to classify, when the onset could not be determined with confidence. Clinical and epidemiological factors collected by DOHMH and supplemented with emergency department records were analyzed.
Results: Thirty-nine PDR COVID-19 cases were identified. The majority had severe disease with 69% presenting to an emergency department within 2 weeks of symptom onset. The first PDR COVID-19 case had symptom onset on 28 January 2020. Only 7 of the 39 cases (18%) had traveled internationally within 14 days of onset (none to China).
Conclusions: COVID-19 was in NYC before being classified as a PHEIC, and eluded surveillance for another month. The delay in recognition limited mitigation efforts; by the time city- and statewide mandates were enacted, 16 and 22 days later, there was already widespread community transmission.
Competing Interests: Potential conflicts of interest. B. T. reports grants or contracts from the CDC, outside the submitted work. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
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