Contact Settings and Risk for Transmission in 3410 Close Contacts of Patients With COVID-19 in Guangzhou, China

Luo, Lei; Liú, Dan; Liao, Xinlong; Wu, Xianbo; Jing, Qinlong; Zheng, Jiazhen; Liu, Fanghua; Yang, Shigui; Bai, Hua; Li, Zhihao; Jian-ping, Liu; Song, Weiqi; Zhu, Wei; Wang, Zhenghe; Zhang, Xiru; Huang, Qingmei; Chen, Peiliang; Liu, Hua‐Min; Cheng, Xin; Cai, Miaochun; Yang, Peng; Yang, Xingfen; Han, Zhigang; Tang, Jin‐Ling; Ma, Yu; Chen, Mao

doi:10.7326/m20-2671

Cited by 209 publications

(259 citation statements)

References 19 publications

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“…Since the vast majority of SARS-CoV-2 infected individuals (i.e., over 85%) now fails to report COVID-19 specific symptoms [21], this approach seems a feasible strategy for avoiding to segregate an immense number of asymptomatic people whose secondary attack rate is limited [22,23], thus preserving testing resources for SARS-CoV-2 positive subjects who carry instead higher risk of household or community virus transmission, as recently highlighted by Qian et al [24]. This strategy would also be in keeping with the allegation of Mina and colleagues [25], according to whom widespread use of rapid and relatively inexpensive antigen tests, although characterized by lower analytic sensitivity compared to conventional molecular assays, shall be regarded as a valuable support for massive SARS-CoV-2 testing.…”

Section: Resultsmentioning

confidence: 99%

Making sense of rapid antigen testing in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics

Mattiuzzi¹,

Henry

Lippi

2020

Diagnosis

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Although the most effective strategy for preventing or containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks relies on early diagnosis, the paramount and unprecedented number of tests needed to fully achieve this target is overwhelming worldwide testing supply and capacity. Molecular detection of SARS-CoV-2 RNA in nasopharyngeal swabs is still considered the reference diagnostic approach. Nonetheless, identification of SARS-CoV-2 proteins in upper respiratory tract specimens and/or saliva by means of rapid (antigen) immunoassays is emerging as a promising screening approach. These tests have some advantages compared to molecular analysis, such as point of care availability, no need of skilled personnel and dedicated instrumentation, lower costs and short turnaround time. However, these advantages are counterbalanced by lower diagnostic sensitivity compared to molecular testing, which would only enable to identifying patients with higher SARS-CoV-2 viral load. The evidence accumulated to-date has hence persuaded us to develop a tentative algorithm, which would magnify the potential benefits of rapid antigen testing in SARS-CoV-2 diagnostics.

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Section: Resultsmentioning

confidence: 99%

Making sense of rapid antigen testing in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics

Mattiuzzi¹,

Henry

Lippi

2020

Diagnosis

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“…Contact age was not associated with susceptibility in 9 studies, 26,28,32,44,47,58,66,67,70 although these were typically less powered to detect a difference. Figure 3 summarizes 15 studies 22,26,29,37,39,42,44,45,47,49,55,59,60,63,65 The second most examined factor was sex of exposed contacts, which was not associated with susceptibility for most studies 20,22,26,32,36,39,44,45,[47][48][49]58,[65][66][67]70 except 3. Spouse relationship to index case was associated with secondary infection in 4 studies 26,45,46,58 of 6 in which this was examined.…”

Section: Jama Network Open | Global Healthmentioning

confidence: 99%

Household Transmission of SARS-CoV-2

et al. 2020

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Key Points Question What is the household secondary attack rate for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)? Findings In this meta-analysis of 54 studies with 77 758 participants, the estimated overall household secondary attack rate was 16.6%, higher than observed secondary attack rates for SARS-CoV and Middle East respiratory syndrome coronavirus. Controlling for differences across studies, secondary attack rates were higher in households from symptomatic index cases than asymptomatic index cases, to adult contacts than to child contacts, to spouses than to other family contacts, and in households with 1 contact than households with 3 or more contacts. Meaning These findings suggest that households are and will continue to be important venues for transmission, even in areas where community transmission is reduced.

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“… 9 In the general community, a study of close contacts from Guangzhou, China, determined symptom severity as a factor correlating with SARS-CoV-2 transmission. 10 …”

Section: Introductionmentioning

confidence: 99%

SARS-CoV-2 seroprevalence and transmission risk factors among high-risk close contacts: a retrospective cohort study

Marimuthu

Koh

et al. 2021

The Lancet Infectious Diseases

197

167

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Background The proportion of asymptomatic carriers and transmission risk factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among household and non-household contacts remains unclear. In Singapore, extensive contact tracing by the Ministry of Health for every diagnosed COVID-19 case, and legally enforced quarantine and intensive health surveillance of close contacts provided a rare opportunity to determine asymptomatic attack rates and SARS-CoV-2 transmission risk factors among community close contacts of patients with COVID-19. Methods This retrospective cohort study involved all close contacts of confirmed COVID-19 cases in Singapore, identified between Jan 23 and April 3, 2020. Household contacts were defined as individuals who shared a residence with the index COVID-19 case. Non-household close contacts were defined as those who had contact for at least 30 min within 2 m of the index case. All patients with COVID-19 in Singapore received inpatient treatment, with access restricted to health-care staff. All close contacts were quarantined for 14 days with thrice-daily symptom monitoring via telephone. Symptomatic contacts underwent PCR testing for SARS-CoV-2. Secondary clinical attack rates were derived from the prevalence of PCR-confirmed SARS-CoV-2 among close contacts. Consenting contacts underwent serology testing and detailed exposure risk assessment. Bayesian modelling was used to estimate the prevalence of missed diagnoses and asymptomatic SARS-CoV-2-positive cases. Univariable and multivariable logistic regression models were used to determine SARS-CoV-2 transmission risk factors. Findings Between Jan 23 and April 3, 2020, 7770 close contacts (1863 household contacts, 2319 work contacts, and 3588 social contacts) linked to 1114 PCR-confirmed index cases were identified. Symptom-based PCR testing detected 188 COVID-19 cases, and 7582 close contacts completed quarantine without a positive SARS-CoV-2 PCR test. Among 7518 (96·8%) of the 7770 close contacts with complete data, the secondary clinical attack rate was 5·9% (95% CI 4·9–7·1) for 1779 household contacts, 1·3% (0·9–1·9) for 2231 work contacts, and 1·3% (1·0–1·7) for 3508 social contacts. Bayesian analysis of serology and symptom data obtained from 1150 close contacts (524 household contacts, 207 work contacts, and 419 social contacts) estimated that a symptom-based PCR-testing strategy missed 62% (95% credible interval 55–69) of COVID-19 diagnoses, and 36% (27–45) of individuals with SARS-CoV-2 infection were asymptomatic. Sharing a bedroom (multivariable odds ratio [OR] 5·38 [95% CI 1·82–15·84]; p=0·0023) and being spoken to by an index case for 30 min or longer (7·86 [3·86–16·02]; p<0·0001) were associated with SARS-CoV-2 transmission among household contacts. Among non-household contacts, exposure to more than one case (multivariable OR 3·92 [95% CI 2·07–7·40], p<0·0001), being spoken to by an index case for 30 min or longer (2·67 [1·21–5·88]; p=0·...

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Contact Settings and Risk for Transmission in 3410 Close Contacts of Patients With COVID-19 in Guangzhou, China

Cited by 209 publications

References 19 publications

Making sense of rapid antigen testing in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics

Making sense of rapid antigen testing in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics

Household Transmission of SARS-CoV-2

SARS-CoV-2 seroprevalence and transmission risk factors among high-risk close contacts: a retrospective cohort study

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