I n December 2019, an outbreak of acute respiratory illness, named as the COVID-19 by the World Health Organization (WHO), emerged in Wuhan, China.[1] The disease quickly spreads to Chinese cities and other parts of the world. The novel coronavirus is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The same as SARS-CoV, the novel coronavirus (SARS-CoV-2) uses angiotensin-converting enzyme 2 (ACE2) receptor to enter the host target cell but mainly spreads through the lower respiratory tract.[2] Previous reports show that fever (98%), cough (76%), dyspnea (55%), myalgia, or fatigue (44%) are the most common complaints of patients.[3-5] Gastrointestinal involvement, a(cute cardiac injury, and acute kidney injury caused by COVID-19 are also reported in other studies.[4,6]. By affecting the respiratory system, COVID-19 rapidly progresses to acute respiratory distress syndrome (ARDS) in some patients and makes them likely to be admitted to the intensive care unit (ICU) or die.[7,8] Nasopharyngeal and oropharyngeal swab specimens tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) are the most commonly used methods to diagnose COVID-19. In this report, we investigate and discuss an unusual case of COVID-19 who was not identified as infected in his first visit despite of performing the RT-PCR test using both nasopharyngeal and oropharyngeal swabs. However, the patient was again referred after 3 days, with a severely progressed ARDS, leading to his death. CASE REPORT A 33-year-old man was referred to the COVID-19 screening clinic of Abu-Ali-Sina Hospital (in Shiraz, Iran), with complaints of dry cough, sore throat, a fever of 38.2°C, chills, muscle pain, and with no other apparent symptoms on April 28, 2020. He had no specific underlying disease, and he denied any involvement with people suspected of having COVID-19. His family members did not have COVID-19 either. On arrival, he had a pulse rate of 80 beats/min, respiratory rate of 16 breaths/min, blood pressure of 115/75 mmHg, and oxygen saturation of 97% on room air, and he did not have dyspnea. Based on his symptoms, the patient was considered a suspected case of COVID-19, according to the Iran Ministry of Health Protocol for COVID-19. Therefore, an RT-PCR test by taking

Due to the lengthy process of producing the COVID-19 vaccine, most countries are trying to implement various low-cost strategies to slow down the spread of the virus and try to normalize the living conditions in society besides reducing the current recession. Comprehension of the cause and effect enables us to analyze, sort out, and explain how changes have happened in the existing problems. In fact, by taking the advantages of Causal Loop Diagrams (CLDs), which reflect the causal connections among components of a system and how changes would affect other components and finally back to itself, we can draw an explicit map of the process of infecting patients by COVID-19.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mainly affects the respiratory system with some patients rapidly progressing to acute respiratory distress syndrome (ARDS). The most common symptoms of the patients are fever, cough, dyspnea, myalgia, and fatigue. Nasopharyngeal and oropharyngeal swab specimens tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) are the most commonly used methods to diagnose COVID-19. Herein, we investigate and discuss a young case of COVID-19, without any pre-existing medical conditions, whose both nasopharyngeal and oropharyngeal swab tests of SARS-CoV-2 were negative in the prodromal phase. However, after three days, with severe dyspnea and rapidly progressed acute respiratory distress syndrome (ARDS), the case was identified as infected by COVID-19 by testing bronchoalveolar lavage fluid (BALF). The patient was intubated in the intensive care unit (ICU) but expired on the fourth day. This case shows the importance of active and accurate monitoring of the patients showing COVID-19 symptoms. Although the BALF test has a higher exposure risk, it is considered more accurate and recommended if performed by an expert operator.