The study population included 21 patients within 8 families with confirmed cases of NCIP. The demographic and clinical characteristics are shown in Table 1. Among all 8 family cluster cases, 4 families had death cases (bold in Table 1).. All deaths were elderly individuals (range, 77–88 years), all ICU and severe cases were also elderly individuals (72–88 years). These cases had nearly the same age range. In addition, the onset of every group of family cases occurred within the same period. Members from each family were infected by SARS-CoV–2 with virtually identical virulence, however younger patients generally presented as non-severe cases while all deaths occurred in elderly patients over the age of 70.
Out of the 12 patients with comorbid conditions (Table 1 and Figure.a),, 2 resulted in deaths, 3 resulted in ICU, 3 resulted in severe cases, and 4 resulted in non-severe cases. In family 1 and 5, each couple had the same onset time, and while both husbands had no comorbid conditions, their wives both had chronic diseases. However, both male patients died while the female patients were still alive after more than 30 days of treatment. In family 4, the elderly parents (4-F1 and 4-M1) became symptomatic on nearly the same date and have the same chronic diseases. However the condition of 4- M1 worsened and he was transferred to the ICU while 4-F1 remained stable. 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.
From these cases, it seems that comorbid conditions are not a major risk factor for mortality, but it most likely to be a key factor that extends the disease duration. Old age is a main risk factor for mortality, but is still not directly related to death of COVID–19. Moreover, although every family has a common living environment, similar dietary structure, same viral infectious condition, and similar onset date, women generally have slower disease progression and stronger living ability.
At the time of admission we collected all patients’ blood routine test results and biochemistry and C-reactive protein (Hs-CRP) results (Table 2).. By comparison, we found there were 20 patients with elevated levels of α-hydroxybutyrate dehydrogenase (α-HBDH) and 14 cases of increased Hs-CRP. The level of α-HBDH had a tendency to be elevated in fatal, ICU, and severe cases, however we could not analyze this due to a small sample size.
Interestingly, 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. Except in one non-severe case, the other cases were all within normal range (1.1- 3.2G/L). According to case records, one non-severe (8-F2) patient in family 8, whose count of lymphocyte fell to 0.76 G/L, had her levels return to normal (1.15 G/L) at one week after admission. Furthermore, the aforementioned 94 years old patient with multiple comorbid conditions, was defined as a non-severe case, and remained stable after 52 days of inpatient treatment. His absolute count of peripheral blood lymphocyte was normal (1.55G/L). In summary, we have identified a decrease in the absolute count of peripheral blood lymphocyte to less than 0.8G/L as one of the key risk factors for COVID–19 mortality, and this factor has been identified as having a direct relationship with disease progression and prognosis.
All 21 cases had received CT scans on admission. The results showed that COVID- 19 had caused varying degrees of destruction to every patients’ lungs. All non-severe and some severe patients’ pulmonary CT presented mild to moderate injury, including local patchy shadowing or ground-glass opacity. All 4 deceased patients’ CT images had displayed bilateral patchy shadowing. The patients with reductions in absolute count of peripheral blood lymphocyte also demonstrated large area bilateral patchy shadowing, as well as declining health (Figure.b).