Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

Abstract

An asymptomatic person infected with severe acute respiratory syndrome coronavirus 2 returned to Heilongjiang Province, China, after international travel. The traveler’s neighbor became infected and generated a cluster of >71 cases, including cases in 2 hospitals. Genome sequences of the virus were distinct from viral genomes previously circulating in China.
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We collected and analyzed epidemiologic data published on the website of the Health Commission of Heilongjiang Province for April 9–23, 2020 (3). We defined confirmed COVID-19 cases as persons who tested positive for SARS-CoV-2 and had clinical symptoms. We defined asymptomatic carriers as persons without clinical symptoms who tested positive for SARS-CoV-2. We refer to case-patients by a letter for each family (A–Z, AA–ZZ), then by the assumed transmission generation (1–2), and finally in sequential order of exposure to SARS-CoV-2–positive persons in generations 1–3 (Figure) (4).

On March 19, 2020, case-patient A0 returned to Heilongjiang Province from the United States; she was asked to quarantine at home. She lived alone during her stay in Heilongjiang Province. She had negative SARS-CoV-2 nucleic acid and serum antibody tests on March 31 and April 3.

Patient B1.1 was the downstairs neighbor of case-patient A0. They used the same elevator in the building but not at the same time and did not have close contact otherwise. On March 26, B1.1’s mother, B2.2, and her mother’s boyfriend, B2.3, visited and stayed in B1.1’s home all night. On March 29, B2.2 and B2.3 attended a party with patient C1.1 and his sons, C1.2 and C1.3.

On April 2, C1.1 suffered a stroke and was admitted to hospital 1. His sons, C1.2 and C1.3, cared for him in ward area 1 of the hospital. Patient C1.1 shared the same clinical team and items, such as a microwave, with other patients in the ward. On April 6, patient C1.1 was transferred to hospital 2 because of fever; C1.2 and C1.3 accompanied him.

On April 7, patient B2.3 first noted symptoms of COVID-19. He tested positive for SARS-CoV-2 on April 9, the first confirmed case in this cluster. His close contacts, B1.1, B2.1, B2.2, and C1.1, subsequently tested positive for SARS-CoV-2 on April 9 or 10. Patient C1.1 was quarantined in hospital 2 when he tested positive on April 9. The epidemiologic investigation showed that none of these 5 persons had a history of travel or residence in affected areas with sustained transmission of SARS-CoV-2 during the 14 days before diagnosis, suggesting that SARS-CoV-2 came from contact with other persons.

During C1.1’s admission at hospital 1, a total of 28 other persons, D1.1–BB1.1, were infected with SARS-CoV-2 in ward area 1. Because all patients in the ward could ambulate, 4 persons, CC1.1, DD1.1, EE1.1, and FF1.1, were infected in other wards and in the computed tomography room of hospital 1. Among hospital 1 staff, 5 nurses and 1 doctor were infected. In hospital 2, another 20 persons, GG1.1–VV1.1, were infected in the ward where C1.1 stayed (Figure).