Increased household secondary attacks rates with Variant of Concern SARS-CoV-2 index cases

IMPORTANCE: Higher secondary attack rates related to variant of concern (VOC) index cases have been reported, but have not been explored within households, which continue to be an important source of coronavirus disease 2019 (COVID-19) transmission OBJECTIVE: To compare secondary attack rates in households with VOC versus non-VOC index cases. DESIGN: A retrospective cohort study of household index cases reported from February 7-27, 2021. A propensity-score matched cohort was derived to calculate adjusted estimates. SETTING: Ontario, Canada. PARTICIPANTS: A population-based cohort of all private households with index cases. We excluded cases in congregate settings, as well as households with one individual or with >1 case with the same earliest symptom onset date. EXPOSURE: VOC status, defined as either individuals confirmed as B.1.1.7 using whole genome sequencing or those that screened positive for the N501Y mutation using real-time PCR. MAIN OUTCOME AND MEASURE: Household secondary attack rate, defined as the number of household secondary cases that occurred 1-14 days after the index case divided by the total number of household secondary contacts. RESULTS: We included 1,259 index VOC and non-VOC cases in the propensity score-matched analysis. The secondary attack rate for VOC index cases in this matched cohort was 1.31 times higher than non-VOC index cases (RR=1.31, 95%CI 1.14-1.49), similar to the unadjusted estimate. In stratified analyses, the higher secondary attack rate for VOC compared to non-VOC index cases was accentuated for asymptomatic index cases (RR=1.91, 95% CI 0.96-3.80) and presymptomatic cases (RR=3.41, 95%CI 1.13-10.26) CONCLUSIONS AND RELEVANCE: This study provides strong evidence of increased transmissibility in households due to VOCs and suggests that asymptomatic and pre-symptomatic transmission may be of particular importance for VOCs. Our study suggests that more aggressive public health measures will be needed to control VOCs and that ongoing research is needed to understand mechanisms of VOC transmissibility to curb their associated morbidity and mortality.

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Effects on clinical outcomes of intensifying triple oral antidiabetic drug (OAD) therapy by initiating insulin versus enhancing OAD therapy in patients with type 2 diabetes: A nationwide population-based, propensity-score-matched cohort study

Diabetes Obesity and Metabolism ◽

10.1111/dom.13525 ◽

2018 ◽

Vol 21 (2) ◽

pp. 312-320 ◽

Cited By ~ 4

Author(s):

Shihchen Kuo ◽

Chun-Ting Yang ◽

Jin-Shang Wu ◽

Huang-Tz Ou

Keyword(s):

Type 2 Diabetes ◽

Cohort Study ◽

Propensity Score ◽

Clinical Outcomes ◽

Population Based ◽

Matched Cohort ◽

Antidiabetic Drug ◽

Oral Antidiabetic Drug ◽

Oral Antidiabetic

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Five‐year effectiveness of bariatric surgery on disease remission, weight loss, and changes of metabolic parameters in obese patients with type 2 diabetes: A population‐based propensity score‐matched cohort study

Diabetes/Metabolism Research and Reviews ◽

10.1002/dmrr.3236 ◽

2020 ◽

Vol 36 (3) ◽

Cited By ~ 2

Author(s):

Tingting Wu ◽

Simon Kin Hung Wong ◽

Betty Tsz Ting Law ◽

Eleanor Grieve ◽

Olivia Wu ◽

...

Keyword(s):

Type 2 Diabetes ◽

Bariatric Surgery ◽

Weight Loss ◽

Cohort Study ◽

Propensity Score ◽

Population Based ◽

Obese Patients ◽

Matched Cohort ◽

Disease Remission

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Increased risk of rheumatoid arthritis in patients with migraine: a population-based, propensity score-matched cohort study

Rheumatology International ◽

10.1007/s00296-016-3604-2 ◽

2016 ◽

Vol 37 (2) ◽

pp. 273-279 ◽

Cited By ~ 9

Author(s):

Yi-Chia Wang ◽

Ya-Ping Huang ◽

Mei-Ting Wang ◽

Hsin-I Wang ◽

Shin-Liang Pan

Keyword(s):

Rheumatoid Arthritis ◽

Cohort Study ◽

Propensity Score ◽

Population Based ◽

Matched Cohort ◽

Matched Cohort Study ◽

Increased Risk

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Variant-of-concern-attributable health and health system-related outcomes: a population-level propensity-score matched cohort study

10.1101/2021.06.02.21257869 ◽

2021 ◽

Author(s):

Aysegul Erman ◽

Sharmistha Mishra ◽

Kali Barrett ◽

Stephen Mac ◽

David MJ Naimark ◽

...

Keyword(s):

Cohort Study ◽

Propensity Score ◽

Health Systems ◽

Wild Type Strain ◽

Severe Disease ◽

Population Level ◽

Population Based ◽

Matched Cohort ◽

Matched Cohort Study ◽

Incident Laboratory

Background: As the transmission of SARS-CoV-2 variants intensifies globally, the burden of COVID-19 on the already strained health systems is becoming increasingly concerning. While there is growing literature on the effects of various variants-of-concern (VOC) on increased transmission, the extent to which VOCs may lead to more severe disease remains debated. Methods: In the current analysis, we use a population-based propensity-score matched cohort study of all incident laboratory-confirmed COVID-19 cases with VOC testing in Ontario, Canada to estimate healthcare resource use and health outcomes attributable to VOCs introduced to Ontario between January 1 and April 9, 2021, relative to the previously circulating wild-type strain. Results: We find that VOCs are associated with a higher odds of hospitalisation (odds ratio [OR], 2.25; 95% confidence interval [CI], 2.10-2.40) and ICU admission (OR, 3.31; 95%CI, 2.84-3.86); as well as with a higher odds of mortality for both the general COVID-19 population (OR 1.75; 1.47-2.09) and hospitalised cases (OR, 1.62; 95%CI, 1.23-2.15). Conclusion: Taken together, these findings suggest that health systems may face increased demand for healthcare resources as VOCs predominate worldwide in view of low global vaccination coverage.

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Role of children in household transmission of COVID-19

Archives of Disease in Childhood ◽

10.1136/archdischild-2020-319910 ◽

2020 ◽

pp. archdischild-2020-319910 ◽

Cited By ~ 13

Author(s):

Jieun Kim ◽

Young June Choe ◽

Jin Lee ◽

Young Joon Park ◽

Ok Park ◽

...

Keyword(s):

Attack Rate ◽

Index Case ◽

Clinical Findings ◽

International Travel ◽

Contact Tracing ◽

Secondary Case ◽

Household Transmission ◽

Household Members ◽

Index Cases

ObjectiveTransmissibility of COVID-19 by children in the household is not clear. Herein, we describe children’s role in household transmission of COVID-19.Design and settingAll paediatric COVID-19 index cases and their household members reported from 20 January to 6 April 2020 in South Korea were reviewed. The secondary attack rate (SAR) from child index case to household secondary case was calculated. Epidemiological and clinical findings of child index case-household secondary case pair was assessed.ResultsA total of 107 paediatric COVID-19 index cases and 248 of their household members were identified. One pair of paediatric index-secondary household case was identified, giving a household SAR of 0.5% (95% CI 0.0% to 2.6%). The index case was self-quarantined at home after international travel, stayed in her room, but shared a meal table with the secondary case.ConclusionThe SAR from children to household members was low in the setting of social distancing, underscoring the importance of rigorous contact tracing and early isolation in limiting transmission within households.

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