Pre-Pandemic COVID-19 in New York City: A descriptive analysis of COVID-19 illness prior to February 29, 2020

Abstract Background On January 30, 2020 the COVID-19 pandemic was declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization. Almost a month later on February 29, 2020, the first case in New York City (NYC) was diagnosed. Methods Three-hundred-sixty persons with COVID-like illness was reported to the NYC Department of Health and Mental Hygiene (DOHMH) before February 29, but 37 of these tested negative and 237 were never tested for SARS-COV-2. Records of 86 persons with confirmed COVID-19 and symptom onset prior to February 29, 2020 were reviewed by four physician-epidemiologists. Case-patients were classified as likely early onset COVID-19, or insufficient evidence to determine onset. Clinical and epidemiological factors collected by DOHMH and supplemented with emergency department records were analyzed. Results Thirty-nine likely early onset COVID-19 cases were identified. The majority had severe disease with 69% presenting to an ED visit within 2 weeks of symptom onset. The first likely COVID-19 case on record had symptom onset on January 28, 2020. Only 7 of the 39 cases (18%) had traveled internationally within 14 days of onset (none to China). Conclusions SARS-CoV-2 and COVID-19 was in NYC before being classified as a PHEIC, and eluded surveillance for another month. The delay in recognition limited mitigation effort and by the time that city and state-wide mandates were enacted 16 and 22 days later there was already community transmission. Key Points Records of 86 persons with confirmed COVID-19 and symptom onset prior to February 29, 2020 were reviewed for likelihood of early onset COVID-19. Thirty-nine likely early onset COVID-19 cases were identified, suggesting that early COVID-19 transmission in NYC went undetected.