key: cord-0890182-307fc6nv authors: Afonso, Eliane T.; Marques, Solomar M.; Costa, Lusmaia D. C.; Fortes, Patrícia M.; Peixoto, Fernanda; Bichuetti‐Silva, Danielli C.; Aredes, Natália D. A.; Rosso, Claci F. W.; Oliveira, Faétila dos S.; Fiaccadori, Fabíola S.; Souza, Menira B. de L. D. e; Silveira‐Lacerda, Elisângela de P.; Bazilio, Gabriela S.; Borges, Clayton L.; Rocha, Juliana A. P.; Naghettini, Alessandra V.; da Costa, Paulo S. S.; Guimarães, Rafael A. title: Secondary household transmission of SARS‐CoV‐2 among children and adolescents: Clinical and epidemiological aspects date: 2021-10-13 journal: Pediatr Pulmonol DOI: 10.1002/ppul.25711 sha: fc6204ec630aa57ec3041f40b4238625fb60f601 doc_id: 890182 cord_uid: 307fc6nv OBJECTIVE: To evaluate the secondary attack rate (SAR) in children and adolescents, contacts of essential activities workers who were infected by SARS‐CoV‐2; and to describe associated clinical and epidemiological data. METHODS: A cross‐sectional study conducted in children and adolescents aged 5 to 19 years of age, that were household contacts of parents and other relatives who were infected by SARS‐CoV‐2 in the city of Goiânia, Central Brazil, from March to October 2020. Sociodemographic and clinical data were collected from all participants. Nasopharyngeal and oropharyngeal swabs were collected and tested for SARS‐CoV‐2 RNA using real‐time reverse transcription polymerase chain reaction (RT‐PCR). Factors associated with SARS‐CoV‐2 infection and SAR were analyzed using Poisson regression. RESULTS: A total of 267 children and adolescents were investigated. The prevalence of SARS‐CoV‐2 RNA by the real‐time RT‐PCR test and/or the presence of COVID‐19 associated symptoms (anosmia/ageusia and flu syndrome) was 25.1% (95.0% Confidence Interval [95.0% CI] = 20.3‐30.6). More than half (55.1%) of the participants had sygns and symptoms. The most prevalent signs and symptoms in positive individuals were nasal congestion (62.7%), headache (55.2%), cough (50.8%), myalgia (47.8%), runny nose (47.8%), and anosmia (47.8%). The Poisson model showed that the following signs or symptoms were associated with SARS‐CoV‐2 infection: fever, nasal congestion, decreased appetite, nausea, anosmia, and ageusia. Families that had more than one infected adult, in addition to the index case, presented greater transmissibility to children and adolescents. CONCLUSIONS: Our results contribute to the hypothesis that children and adolescents are not important sources of transmission of SARS‐CoV‐2 in the home environment during a period of social distancing and school closure; even though they are susceptible to infection in the household (around ¼ of our study population). In the global scenario, Brazil emerged as one of the countries that has suffered the highest impact of COVID-19 in the world; the emergence of new variants of the virus among other factors, such as low testing and failure to comply with measures of social distancing, have contributed to its rapid dispersion in all major regions of the country. It is currently the second country with the highest record of accumulated cases (14, 122, 795) and deaths (400,000) in the world. 2 The urgent need to understand the different aspects of COVID-19 and its natural history has quickly resulted in numerous published studies on the topic with substantial contributions about the disease, the management of patients, as well as the development of vaccines in record time. Specificities in the clinical presentations of COVID-19 and the transmissibility of SARS-CoV-2 were found in different populations and age groups. 3, 4 Despite advances, some questions related to the clinical and epidemiological aspects of COVID-19 continue to require evidence in the pediatric population, especially in children and adolescents who did not require hospitalization. Studies show that in children and adolescents, SARS-CoV-2 infection ranges from asymptomatic presentation to severe clinical symptoms with a greater predominance of mild to moderate conditions. 5 The most common clinical manifestations of in the pediatric population have been a variety of signs and symptoms related to acute upper respiratory tract infection such as fever, fatigue, cough, sore throat, nasal congestion, and shortness of breath. 6 In more severe cases, patients may progress to respiratory failure, kidney injury, shock, and coagulation dysfunction, requiring mechanical ventilation and admission to the intensive care unit (ICU). 7 However, some particularities in the clinical manifestations of COVID-19 in children have drawn attention as cases associated with multisystemic inflammatory syndrome and Kawasaki syndrome that have been reported in the pediatric population. 8, 9 Estimates by the Centers for Disease Control and Prevention, during the first months of the pandemic in 2020, show that 1.7% of the total reported cases of COVID-19 occurred in children under 18 years old, and 5.6% of the children who developed symptoms evolved in need of hospitalization. 10 In Wuhan, the first epicenter of COVID-19 in the world, children, and adolescents aged 6-19 were susceptible to infection by the SARS-CoV-2 in their household, in the presence of a primary case; with a SAR of 10.8% for the assessed period. 13 A study in Singapore reported secondary transmission of SARS-CoV-2 from an adult to a household contact child in 5.2% of evaluated families. 14 In Brazil, a multicenter study found that 39% of the 79 children admitted to an ICU because of COVID-19 had contact with a suspected case, with 87% of cases from the home environment. 15 The increasing number of illness cases among essential activities workers, such as those in the health field, has been one of the relevant aspects in the epidemiology of COVID-19 and makes the occupational risk of infection by SARS-CoV-2 evident. The concern with the occurrence of secondary transmission from these professionals to other people in the community, including their family nuclei, became the object of study in different places during the pandemic. 16 In this context, the objective of this study was to estimate the rate of secondary attack in children and adolescents, home contacts of workers in essential activities, who were diagnosed with COVID-19, and to describe clinical and epidemiological aspects in this population. This is a cross-sectional and analytical study that investigated the secondary transmission of SARS-CoV-2 in children and adolescents, household contacts of essential activities workers which had been positive for SARS-CoV-2 RNA by molecular testing. The study was carried out in the city of Goiânia, capital of the state of Goiás (Midwest Region of Brazil), a city with approximately 1,536,097 inhabitants, 298,043 of whom are between 5 and 19 years old. 17 Currently, Goiânia is a regional and national reference of the Brazilian Some restrictive government measures to control the progress of the pandemic in the state of Goiás were adopted as of March 2020, with the suspension of nonessential activities. In-person school activities were suspended within the public and private education sectors and were only partially resumed in January 2021. This study was carried out between June 15 and October 28, 2020, and it had as its starting point the identification of workers of essential activities diagnosed with COVID-19, and confirmed by RT-PCR, designated index cases. The workers in essential activities within the index cases group were: (i) health care workers (HCWs) (68.9%) such as doctors, nurses, nursing technicians, physiotherapists, among others, (ii) public security workers (PSWs) (5.6%), such as police and security guards, (iii) universitylevel education workers, including administrative workers, teachers, and technicians (13.1%); and (iv) others workers as urban cleaning professionals and others (12.4%). Recruitment took place at the research center structured for the development of the study. An announcement about the objectives, target audience and methods was released by the official media and websites. The attendance of the index cases occurred by appointment, and all were tested at the research center. The base sampling of recruitment of index cases was of the non-probabilistic type. Based on the identification of the index cases, an investigation was carried out aiming at the analysis of the secondary transmission of SARS-CoV-2 to children and adolescents, who presented or not COVID-19 symptoms, in their household. In the present study, the following inclusion criteria were adopted: The research data collection was performed by experienced and previously trained professionals and researchers. On the day of each participant's attendance at the sample collection site, an interview was conducted with the legal guardian to obtain sociodemographic data and potential factors associated with SARS-CoV-2 infection. Variables related to clinical sygns or symptoms, housing conditions, and care related to the prevention of COVID-19 adopted at home were part of these instruments. A confirmed case of COVID-19, by clinical-epidemiological criteria, was defined as an individual with nondetectable SARS-CoV-2 RNA by RT-PCR in nasopharyngeal and oropharyngeal swab but that presented the following criteria: Flu Syndrome or Severe Acute Respiratory Syndrome associated with anosmia (olfactory dysfunction) or ageusia (gustatory dysfunction) without any other previous cause; in addition to a history of home contact with an index case. 19 Recommendations and guidelines from the Ministry of Health of Brazil were used as a theoretical reference for the classification of clinical presentations of COVID-19 in Flu Syndrome mild, moderate or Severe Acute Respiratory Syndrome. 19 The presence of rash and conjunctivitis were considered as possible atypical signs of COVID- For analysis purposes, the clinical signs and symptoms reported by home contacts, on the swab collection date, were grouped into categories: (i) systemic: fever, myalgia, fatigue, arthralgia, and hypoxia; (ii) high respiratory: sore throat, runny nose, nasal congestion; (iii) low respiratory: cough, dyspnea, chest pain; (iv) neurological: headache, anosmia, ageusia; (v) digestive: abdominal pain, nausea, vomiting, and diarrhea; (vi) rash and conjunctivitis. The data were analyzed using the Statistical Package for the Social Sciences software, 25.0 version. The Kolmogorov-Smirnov normality test with Lilliefors correction was used to evaluate the normality of the variable age. Initially, an exploratory analysis of the main demographic, clinical, and laboratory characteristics of the study participants was carried out. Quantitative variables were described as the median and interquartile range (IQR) due to the absence of normality. Qualitative variables were described as absolute (n) and relative (%) frequencies. Then, the two groups (positive or negative for SARS-CoV-2) were compared using Fisher's exact test (qualitative variables) or Mann-Whitney U test (quantitative variables). Variables related to signs and symptoms with, sex and, age (quantitative variable) of children and adolescents were included in the regression model (p-value < .20) with robust variance, to verify the signs and symptoms associated with SARS-CoV-2 infection. The results of the regression model were presented with aPR (adjusted prevalence ratio), 95.0% Confidence Interval (95.0% CI), regression coefficient (β), and p value. Statistical significance was established using the Wald test. The sensitivity analysis of the signs and symptoms associated with SARS-CoV-2 infection was also conducted including positivity as a dependent variable only by laboratory confirmation. Also, confirmed cases of SARS-COV-2 infection were grouped into symptomatic and asymptomatic groups and compared concerning the variables sex, age (quantitative variable and age group), race/skin color, comorbidities, and viral load (quantitative variable and viral load group) using Mann-Whitney U test or Fisher's exact test. The SAR was calculated for households with a single primary In all analyzes, variables with a p-value <0.05 were considered statistically significant. The prevalence of SARS-CoV (Table 2 ). There was a statistical difference regarding the clinical presentation forms between the groups (p-value < .001). The sensitivity analysis of factors associated with SARS-CoV-2 was 3.5 | Comparison between symptomatic and asymptomatic SARS-CoV-2 infection Table 4 summarizes the characteristics of children and adolescents according to the presence or absence of signs and symptoms associated with SARS-CoV-2 infection. There was no significant difference considering age group, race/skin color, comorbidity, and viral load (Ct) between the symptomatic and asymptomatic groups (p-value ≥ .05). However, the median age was statistically higher in symptomatic individuals when compared to asymptomatic individuals (14 years vs. 10 years; p-value = .022). Regarding viral loads, we found a median Ct of 31 (IQR = 11). We also observed that 52.1% of the children had what was considered low viral loads. We did not find a significant median difference in viral loads between symptomatic and asymptomatic patients (p-value = .280). In our study, fever, nasal congestion, lack of appetite, and nausea were associated with infection by SARS-CoV-2 in multiple regression analysis. However, these sygns and symptoms are frequently present in other respiratory virus infections that are common during childhood. 28, 29 Therefore, the similarity of these associated COVID-19 symptoms with those of different viral infections can prevent suspected cases of the disease from being recognized and contribute to an underestimated number of cases in this age group. It has been indicated that fever and cough are the most prevalent sygns and symptoms of COVID-19 in children and adolescents, 7, 15, 25 and an meta-analysis studyalso revealed that the most common clinical sygns and symptoms of COVID-19 in this population were fever and cough. 30 In our study sample, upper respiratory symptoms, especially nasal congestion; and neurological symptoms, especially headache, were the most prevalent in COVID-19 patients, as reported by other studies. 7, 9, 11 It is important to note that these symptoms do not Our study has some limitations. Furthermore, all children and adolescents were tested, regardless of the date, distance kept from the index case, and time of contact with the index cases (data not available), in addition to being tested only once and, in the case of symptomatic cases, we did not consider the date of onset of symptoms and also did not conduct serologic tests, which may have underestimated the magnitude of the verified rates. However, our study has several strengths. A relatively robust sample was used, when compared to previously published investigations, espe- The authors declare that there are no conflict of interests. | 173 conceptualization (equal); data curation (equal); investigation (equal) methodology (equal); validation (equal) visualization (equal); writing original draft (equal). Patrícia M. Fortes: conceptualization (equal); data curation (equal); investigation (equal); methodology (equal); writing original draft (equal). Fernanda Peixoto: conceptualization (equal); data curation (equal); investigation (equal); methodology (equal); writing original draft (equal) data curation (equal); investigation (equal); methodology (equal). Natália D. A. Aredes: conceptualization (equal); investigation (equal); methodology (equal); writing original draft (equal). Claci F. W. Rosso: conceptualization (equal) Faétila dos S. Oliveira: conceptualization (equal); data curation (equal) writing review & editing (equal). Menira B. de L. D. e Souza: methodology (equal); writing review & editing (equal) Silveira-Lacerda: methodology (equal). Clayton L. Borges: conceptualization (equal); data curation (equal); methodology (equal) conceptualization (equal); data curation (equal); methodology (equal). Alessandra V. Naghettini: conceptualization (equal); data curation (equal); investigation (equal); methodology (equal); project administration (equal); supervision (equal); validation (equal); visualization (equal); writing original draft (equal) conceptualization (equal); data curation (equal) methodology (equal); writing original draft (equal); writing review & editing (equal). Rafael A. 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