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BackgroundApproximately 67% of U.S. households have pets. Limited data are available on SARS-CoV-2 in pets. We assessed SARS-CoV-2 infection in pet cohabitants as a sub-study of an ongoing COVID-19 household transmission investigation. MethodsMammalian pets from households with [≥]1 person with laboratory-confirmed COVID-19 were eligible for inclusion from April-May 2020. Demographic/exposure information, oropharyngeal, nasal, rectal, and fur swabs, feces, and blood were collected from enrolled pets and tested by rRT-PCR and virus neutralization assays. FindingsWe enrolled 37 dogs and 19 cats from 34 of 41 eligible households. All oropharyngeal, nasal, and rectal swabs tested negative by rRT-PCR; one dogs fur swabs (2%) tested positive by rRT-PCR at the first animal sampling. Among 47 pets with serological results from 30 households, eight (17%) pets (4 dogs, 4 cats) from 6 (20%) households had detectable SARS-CoV-2 neutralizing antibodies. In households with a seropositive pet, the proportion of people with laboratory-confirmed COVID-19 was greater (median 79%; range: 40-100%) compared to households with no seropositive pet (median 37%; range: 13-100%) (p=0.01). Thirty-three pets with serologic results had frequent daily contact ([≥]1 hour) with the human index patient before the persons COVID-19 diagnosis. Of these 33 pets, 14 (42%) had decreased contact with the human index patient after diagnosis and none (0%) were seropositive; of the 19 (58%) pets with continued contact, 4 (21%) were seropositive. InterpretationsSeropositive pets likely acquired infection from humans, which may occur more frequently than previously recognized. People with COVID-19 should restrict contact with animals. FundingCenters for Disease Control and Prevention, U.S. Department of Agriculture
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A better understanding of SARS-CoV-2 transmission from children and adolescents is crucial for informing public health mitigation strategies. We conducted a retrospective cohort study among household contacts of primary cases defined as children and adolescents aged 719 years with laboratory evidence of SARS-CoV-2 infection acquired during an overnight camp outbreak. Among household contacts, we defined secondary cases using the Council of State and Territorial Epidemiologists definition. Among 526 household contacts of 224 primary cases, 48 secondary cases were identified, corresponding to a secondary attack rate of 9% (95% confidence interval [CI], 7%-12%). Our findings show that children and adolescents can transmit SARS-CoV-2 to adult contacts and other children in a household setting.
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BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), presents with a broad range of symptoms. Existing COVID-19 case definitions were developed from early reports of severely ill, primarily hospitalized, patients. Symptom-based case definitions that guide public health surveillance and individual patient management in the community must be optimized for COVID-19 pandemic control. MethodsWe collected daily symptom diaries and performed RT-PCR on respiratory specimens over a 14-day period in 185 community members exposed to a household contact with COVID-19 in the Milwaukee, Wisconsin and Salt Lake City, Utah metropolitan areas. We interpreted the discriminatory performance (sensitivity, specificity, predictive values, F1 score, Youdens index, and prevalence estimation) of individual symptoms and common case definitions according to two principal surveillance applications (i.e., individual screening and case counting). We also constructed novel case definitions using an exhaustive search with over 73 million symptom combinations and calculated bias-corrected and accelerated bootstrap confidence intervals stratified by children versus adults. FindingsCommon COVID-19 case definitions generally showed high sensitivity (8696%) but low positive predictive value (PPV) (3649%; F1 score 5263) in this community cohort. The top performing novel symptom combinations included taste or smell dysfunction. They also improved the balance of sensitivity and PPV (F1 score 7880) and reduced the number of false positive symptom screens. Performance indicators were generally lower for children (<18 years of age). InterpretationExisting COVID-19 case definitions appropriately screened in community members with COVID-19. However, they led to many false positive symptom screens and poorly estimated community prevalence. Absent unlimited, timely testing capacity, more accurate case definitions may help focus public health resources. Novel symptom combinations incorporating taste or smell dysfunction as a primary component better balanced sensitivity and specificity. Case definitions tailored specifically for children versus adults should be further explored. FundingThis research was wholly supported by the U.S. Centers for Disease Control and Prevention. DisclaimerThe findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the U.S. Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSCoronavirus disease 2019 (COVID-19) incidence has accelerated globally over the last several months. As the full spectrum of clinical presentations has come into clearer focus, symptom-based clinical screening and case surveillance has also evolved. Preliminary understanding of the clinical manifestation of COVID-19 was driven primarily by descriptions of hospitalized patients, as early testing algorithms prioritized more severely ill persons with classic lower respiratory symptoms and fever. Since then, more data from ambulatory settings have emerged. We searched PubMed from 1 December 2019 to 21 August 2020 for studies that assessed the diagnostic performance of case surveillance definitions for COVID-19. We found no studies examining the discriminatory performance of case surveillance definitions among contacts with mild to moderate symptoms with documented exposure to persons with COVID-19. Nonetheless, we found nine highly relevant studies: seven original reports and two review articles. Five original studies evaluated individual, self-reported symptoms (two among healthcare workers in the United States, one among healthcare workers in the Netherlands, and one online survey for the general public in Somalia) and concluded that using dysfunction of taste or smell for routine COVID-19 screening likely had utility. The fifth study had a similar conclusion based on self-reported symptoms and laboratory results collected via smartphone from the general public in the United States and the United Kingdom. Another original study modeled the substantial effect that multiple revisions to the COVID-19 case definition had on the reported disease burden in the Chinese population. Lastly, an original study illustrated the shift in discriminatory performance of established influenza surveillance case definitions for influenza between adults and children. Age-specific differences in case definition performance may also apply to COVID-19. Two articles reviewed predictive algorithms to define outpatient COVID-19 illness and risk of hospitalization. The reviewed studies were limited in that they were either restricted to individual signs or symptoms, or they incorporated blood tests or imaging that required in-person access to medical care. Added value of this studyThe discriminatory performance of case surveillance definitions for COVID-19 is important for implementing effective epidemic mitigation strategies. Our study illustrates the performance of case definitions in community members with household exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) based solely on symptom profiles. Prior work overrepresented healthcare workers or otherwise studied non-representative populations, and they did not examine across the age spectrum. Our study also provides a novel framework for refining definitions. Using 15 symptoms associated with COVID-19 for all contacts regardless of disease status, we systematically evaluated the discriminatory performance of individual symptoms and previously defined case surveillance definitions across ages and according to two core surveillance applications: 1) screening non-hospitalized individuals to prioritize public health interventions, and 2) estimating the number of non-hospitalized persons with COVID-19 (i.e., community-based syndromic surveillance). We also constructed novel symptom combinations that effectively performed both functions and improved upon widely used case surveillance definitions that may help to target interventions in the absence of unlimited laboratory diagnostic capacity. Our analyses highlight the importance of ongoing re-evaluation of symptom-based surveillance definitions to suit the intended purpose and population under surveillance. Based on our results, which were derived from household members of all ages, case surveillance definition performance may improve if developed separately for adults and children. Implications of all the available evidenceCase definitions for COVID-19 should be tailored to maximize the discriminatory performance dependent upon its intended use. Existing COVID-19 case definitions screened in most community members with COVID-19, but also yielded a high number of false positive results. When unlimited, timely diagnostic testing is not available symptom combinations with improved accuracy (i.e., more balanced sensitivity and specificity) may help focus resources, such as recommending self-isolation among community contacts.
