Nosocomial cluster of infection
The first patient (case 1) is a 46-year-old female nurse with no significant medical history. She presented with 2 days of sore throat and dry cough staring on January 1. Then, she gradually developed mild fever (37.8ºC) two days later, and her symptoms were relieved by nonsteroidal anti-inflammatory drugs. She took oseltamivir (75 mg) orally twice a day for five days, but she had a fever again (37.5ºC to 38.5ºC) and felt shortness of breath after general physical activity. Routine blood testing showed normal white blood cell (WBC) count (5.08×109/L) with lower lymphocyte counts (1.06×109/L). High-sensitivity C-reactive protein (hsCRP) test results were within the normal ranges (0.5 mg/L, normal <8.0 mg/L). Throat swabs were negative results for influenza A, influenza B and respiratory syncytial virus. She had chest CT with multiple ground glass-like-lung lesions indicative of viral pneumonia on d10 (Figure 2). Nasopharyngeal and throat swabs for SARS-CoV-2 were performed twice but negative for SARS-CoV-2 RNA under RT-PCR. As a suspicious case of COVID-19, she was self-quarantined at home from d18 (January 18). Based on the established therapeutic and triage strategy of Wuhan Union Hospital9, she was treated with oral of 200mg arbidol three times a day and 0.4 moxifloxacin once daily for 10 days. Her symptoms gradually resolved and repeat chest CT showed absorbance of lesions after 4 weeks (Figure 2). She returned for follow-up two weeks later and tested positive for anti-SARS-CoV-2 IgM and IgG under serological detection at recovery stage. She now remains well and symptom free.
Cases 2 to 4 worked in the same ward with case 1. Case 2 was a 33-year-old male surgeon with no significant medical history. He presented with mild fever (37.8 ºC), fatigue and muscle soreness on January 8. He had typical changes in lymphocyte counts. His chest CT on d4 showed multiple ground glass-like lung lesions (Figure 2). The nucleic acid tests were negative for SARS-CoV-2 RNA twice. He was self-quarantined at home and treated with 300mg intravenous ribavirin for 7 days, along with oral of 200mg arbidol three times a day and 0.4 moxifloxacin for 10 days. Absorbance of glass-like lung lesions in chest CT was visible one week later (Figure 2). He showed positive anti-IgG for serological detection of SARS-CoV-2 and confirmed previous infection.
Case 3 was a 54-year-old female nurse with a 10-years history of primary hypertension. She presented with fatigue and diarrhea starting January 8. She was confirmed to have COVID-19 with positive SARS-CoV-2 RNA and typical chest CT findings on January 18 (Figure 2). She was then admitted to hospital for isolated treatment. After supportive care, antiviral drugs (arbidol) and intravenous dexamethasone, she soon recovered, with chest CT absorbance and cessation of symptoms after six days of hospitalization. The SARS-CoV-2 RNA of the nasal swabs was not detected after treatment. She showed positive anti-IgM/IgG for serological detection of SARS-CoV-2 at recovery stage.
Case 4 is a 31-year-old female nurse with no significant medical history. She presented with fatigue and dry cough since January 18. She had typical chest CT findings (Figure 2) with WBC change and confirmed COVID-19 diagnosis on d8 (January 26) with positive SARS-CoV-2 RNA by nasal swab. She was admitted to the hospital for isolated treatment when confirmed. After supportive care, antiviral drugs (arbidol), intravenous antibiotics (moxifloxacin) and dexamethasone, she recovered with chest CT absorbance and cessation of symptoms after 25 days of hospitalization. No SARS-CoV-2 was detected in a nasal swab after treatment. She showed positive anti-IgM and IgG for serological detection of SARS-CoV-2. The clinical and laboratory examination results of this cluster SARS-CoV-2 nosocomial infection are outlined in Table 1.
Familial cluster of infection following the first cluster
For case 3, her 59-year old husband and 29-year old daughter who lived in the same household with case 3 were presented respiratory symptoms several days later, but both were negative nasopharyngeal swab tests of SARS-CoV-2 RNA. As a highly suspicious cases due to the close contact of case 3 and their typical chest CT findings (Figure 2), they received isolated treatment soon. Both were recovered after 13 days of hospitalization. Both had positive anti-IgG for serological detection and proved their previous SARS-CoV-2 infection. For the other three health care providers, no familial cases of SARS-CoV-2 infection were identified. The clinical and laboratory examination results of this sequential familial cluster are outlined in Table 1.