Features of family clusters of COVID-19 patients: A retrospective study

Abstract

Background: To investigate and compare the clinical and imaging features among family members infected with COVID-19.

Methods: We retrospectively collected a total of 34 COVID-19 cases (15 male, 19 female, aged 48 ± 16 years, ranging from 10 to 81 years) from 13 families from January 17, 2020 through February 15, 2020. Patients were divided into two groups: Group 1 - part of the family members (first-generation) who had exposure history and others (second-generation) infected through them, and Group 2 - patients from the same family having identical exposure history. We collected clinical symptoms, laboratory findings, and high-resolution computed tomography (HRCT) features for each patient. Comparison tests were performed between the first- and second-generation patients in Group 1.

Results: In total there were 21 patients in Group 1 and 20 patients in Group 2. For Group 1, first-generation patients had significantly higher white blood cell count (6.5 × 10⁹/L (interquartile range (IQR): 4.9-9.2 × 10⁹/L) vs 4.5 × 10⁹/L (IQR: 3.7-5.3 × 10⁹/L); P = 0.0265), higher neutrophil count (4.9 × 10⁹/L (IQR: 3.6-7.3 × 10⁹/L) vs 2.9 × 10⁹/L (IQR: 2.1-3.3 × 10⁹/L); P = 0.0111), and higher severity scores on HRCT (3.9 ± 2.4 vs 2.0 ± 1.3, P = 0.0362) than the second-generation patients. Associated underlying diseases (odds ratio, 8.0, 95% confidence interval: 3.4-18.7, P = 0.0013) were significantly correlated with radiologic severity scores in second-generation patients.

Conclusion: Analysis of the family cluster cases suggests that COVID-19 had no age or sex predominance. Secondarily infected patients in a family tended to develop milder illness, but this was not true for those with existing comorbidities.

Keywords: COVID-19; CT; Family cluster; Pneumonia.

Fig. 1

The enrolled families and the family members. A total of 13 families were included and sorted into Group 1 and Group 2. For patients in Group 1, a clear time order of infection could be recognized as only the patients in the first line (first generation) had exposure history, patients in the second line (second generation) were assumed to be infected by the patients in the first line (the dashed arrow). For patients in Group 2, the patients in a same family had shared exposure history and thus no time order could be decided.

Fig. 2

Paired comparison of the severity scores on HRCT between the first- and second-generations in each family of Group 1. A notably higher severity scores could be found in all the families except for family e. (Fam: family; HRCT: high-resolution CT).

Fig. 3

Case study of family c. Graph A presented coronary CT image of a 47-year-old male (without underlying disease) who had a traveling history (not Wuhan) within two weeks before the illness onset. Diffuse ground glass opacities (GGO) could be found at both lungs (arrow), as well as the presence of consolidation at both the lower lobes. Graph B presented coronary CT images of a 76-year-old female (mother of patient in graph A, without underlying disease) who had no other exposure history but developed symptoms after close contact with the patient in graph A. Smaller but diffuse GGO could be found for this patient, without presence of consolidation.

Fig. 4

Case study of family e. Graph A presented axial CT image of a 49-year-old male (without underlying disease) who came back from Wuhan within two weeks before the illness onset. Only several ground glass opacities (GGO) could be found at the right upper lobe. Graph B came from an 81-year-old male (father of the patient in Graph A, with chronic obstructive pulmonary disease) whose only exposure history was the close contact with his son. Diffuse patchy GGO was found for this patient, as well as evidence of fibrosis.