Clinical laboratory and dispersion pattern of COVID-19 in a family cluster in the social-distancing period

Abstract

Introduction: Since the first reports of coronavirus disease 2019 (COVID-19) in December 2019, the disease has spread worldwide. Different social isolation strategies have been adopted to reduce community transmission, but few studies have evaluated the pattern of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection in a family cluster during periods of isolation. We report an outbreak in 24 members of a family cluster during a period of social distancing.

Methodology: We carried out an observational descriptive study of a family cluster infected with SARS-CoV-2 in Pernambuco, Northeast Brazil. Laboratory confirmation included RT-PCR of nasopharyngeal samples or IgM or IgG serology.

Results: The attack rates were 75% (19/24) based on laboratory-confirmed cases and 87.5% (21/24) including probable cases. The time of spread was 17 days from the first case. All patients had mild symptoms, requiring no hospitalization, and none of them died. The frequency of symptomatic, laboratory-confirmed patients was higher among adults (94%) than among children (50%); the paediatric age group also had a higher frequency of exposed individuals who remained negative for infection. Ground-glass opacities on chest computed tomography were present in all patients with reported dyspnoea.

Conclusion: This study highlights a high risk of intrahousehold transmission from an index case, suggesting the need for (I) specific guidelines during periods of social distancing, (II) minimization of external exposures and, above all, (III) adoption of strict quarantine measures for suspected cases and family members to prevent outbreaks from spreading.