An analysis of eight family cluster cases in Wuhan, China: Peripheral blood lymphocyte count may predict Covid-19 mortality

Background: Since December 2019, a novel coronavirus (SARSCoV-2) causing COVID-19 has spread across the world in a global pandemic. Tens of thousands of people were infected, several thousand patients died. However, key risk factors for predicting mortality remain unclear. This study aims to analyze the differences in mortal risk factors between fatal and non-fatal cases within each family, to identify the key risk factors for COVID-19 mortality. Method: Retrospective, randomly selected eight family clusters consisting of 21 individual cases who had been confirmed positive for SARS-CoV-2 and admitted to the Wuhan Union Hospital, Wuhan, China, from February 6 to March 3, 2020. Clinical characteristics and demographic data were tracked up to March 3. Results: Among all 8 family cluster cases, 4 families had death cases. All deaths were elderly individuals (range, 77-88 years), all ICU and severe cases were also elderly individuals (72-88 years). Patient 2-M1, who was the oldest of all cases and first confirmed with COVID-19 on January 10, had four critical comorbid conditions including colon cancer, COPD, hypertension, and coronary disease. But he remains in stable condition after more than 50 days of inpatient treatment. We observed that the absolute count of peripheral blood lymphocyte dropped to less than 0.8G/L of all death and ICU cases, ranging from 0.22 G/L to 0.81 G/L. Conclusions: We found that elderly age is one of the main risk factors for mortality, comorbidities were not predictive of mortality due to COVID-19, although they may extend disease duration. Importantly, we discovered that within our study population the absolute count of peripheral blood lymphocyte is a predictive risk factor for mortality due to COVID-19, establishing that it may be a very important factor for judging a patient's prognosis.