Coronaviruses such as SARS-CoV2, MERS-CoV, and SARS-CoV can cause significant morbidity and mortality in infected persons. Lung is the most common site of infection for these viruses, which may manifest as acute respiratory distress syndrome and mortality. Pulmonary involvement is also responsible for the high viral transmission The aim of this study is to evaluate BAL in post-acute COVID-19 patients for:Cytological and cellular patterns. Microbial analysis for possibility of presence of bacterial, mycobacerial or fungal co-infection.PCR for corona virus

On December 31, 2019, a cluster of cases of pneumonia in people who were later linked to Wuhan Seafood Market in Wuhan, Hubei, China, were reported. Just a week later, Chinese health authorities confirmed that those cases were caused by a novel coronavirus, later named as SARS-CoV2 .

Till date, six coronavirus species are known to cause human diseases. Four of the already-known coronavirus species, i.e., 229E, OC43, NL63, and HKU1, are commonly circulating viruses in human population and cause mild common cold-like symptoms.

Two of the already-known strains of coronavirus, severe acute respiratory syndrome-coronavirus (SARS-CoV) and Middle East respiratory syndrome-CoV (MERS-CoV) are zoonotic in origin and cause serious illnesses which can be fatal.

Coronaviruses such as SARS-CoV2, MERS-CoV, and SARS-CoV can cause significant morbidity and mortality in infected persons. Lung is the most common site of infection for these viruses, which may manifest as acute respiratory distress syndrome and mortality. Pulmonary involvement is also responsible for the high viral transmission.

BAL, bronchial wash, and protected specimen brush are bronchoscopic procedures used to provide microbiological samples from lower respiratory airways. However, because of the risk of viral transmission, bronchoscopy is not routinely indicated for the diagnosis of COVID-19.

Even if SARS-CoV-2 shares similarities with the other coronaviruses, the higher diffusion rate and the possibility to induce fatal complications, such as severe pneumonia, acute respiratory distress syndrome (ARDS), thrombosis, septic shock and organ failure, make this virus a major public health threat.

Since the first guidelines for autopsy on both confirmed and suspected COVID-19-positive patients were published in February 2020, an increasing number of biopsies and autopsies have been performed. However, our knowledge regarding the precise nature of the immunological defense in various organ systems in response to viral infection, as well as the response patterns in specific tissues, is largely incomplete but is essential in order to initiate timely and targeted antiviral, anti-inflammatory, anticoagulative, or even antifibrotic therapy .

As of yet, most research papers have focused on the inflammatory status at the plasma level of COVID-19 patients. However, because the main target organ is the lung, it is crucial to understand the inflammatory status at the deep lung level during different stages of the infection. Currently, limited data are available about alveolar inflammatory status in COVID-19 patients because of concerns in relation to using bronchoscopy to avoid aerosol generation. The aim of this study is to evaluate BAL in post-acute COVID-19 patients for:Cytological and cellular patterns. Microbial analysis for possibility of presence of bacterial, mycobacerial or fungal co-infection.PCR for corona virus

Inclusion Criteria:

• Patients with persistent pulmonary infiltrate one month after discharge from isolation building at Mansoura university hospitals, previously tested positive for SARS-CoV-2 infection by real-time PCR on nasopharyngeal swab during admission, discharged and discontinued transmission based precautions according to CDC guidance:

Symptom-Based Strategy for Discontinuing Transmission-Based Precautions (CDC, 2020)

Patients with mild to moderate illness who are not severely immunocompromised:

• At least 10 days have passed since symptoms first appeared and
• At least 24 hours have passed since last fever without the use of fever-reducing medications and
• Symptoms (e.g., cough, shortness of breath) have improved

Patients with severe to critical illness or who are severely immunocompromised1:

• At least 10 days and up to 20 days have passed since symptoms first appeared and
• At least 24 hours have passed since last fever without the use of fever-reducing medications and
• Symptoms (e.g., cough, shortness of breath) have improved
• Consider consultation with infection control experts

Exclusion Criteria:

• Age: patients less than 18 years old.
• Patient refuse to undergo bronchoscopy.
• Patients unfit for bronchoscopy (hemodynamic instability, recent myocardial infarction, severe hypoxia, uncooperative patient, severe bleeding disorder).
• Patients known to have chronic airway pulmonary diseases or interstitial lung diseases