We encountered two female patients with COVID-19 ―one transferred from the cruise ship, Diamond Princess, docked in the Yokohama port, and the other with community transmission of the infection. The former patient had asymptomatic pneumonia, which subsided spontaneously. The latter patient suffered from severe rapidly worsening pneumonia which necessitated mechanical ventilation and extracorporeal membrane oxygenation, but eventually showed complete resolution of the disease. Although the lung involvement in those two cases at their first evaluation seemed to be equal, they exhibited very different clinical courses ―one showing self-limiting asymptomatic pneumonia and the other showing severe progressive pneumonia.
The patient, an 83-year-old woman, lived with her daughter, at whose workplace, a person had been diagnosed as having COVID-19. The daughter was admitted to the hospital for pneumonia, however, the results of the PCR test for SARS-CoV-2 performed twice were negative. The patient developed fever a few days later, and visited an outpatient clinic for patients with fever and a history of travel abroad. The result of a nasal swab PCR test was negative, and antibiotics were prescribed. While the fever gradually subsided,the patient began to experience dyspnea. Therefore, she visited the outpatient clinic again for a repeat nasal swab test. Meanwhile, the dyspnea became severe and she was transported to our hospital. Immediately after admission, she was intubated and initiated on mechanical ventilation. A nasal swab and a specimen of lower respiratory tract secretions were submitted for COVID-19 testing by PCR, and while the nasal swab test result was negative again, the lower respiratory tract specimen yielded a positive result. The possibility of false-negative results of PCR testing for SARS-CoV-2 should be borne in mind in close contacts or strongly suspected cases of COVID-19. PCR testing of specimens of lower respiratory tract secretions might be necessary for suspected cases of COVID-19 pneumonia.
