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Kadowaki M, Yasuoka K, Takahashi C, Mukoyama H, Shirayama Y, Yuasa M. An analysis of factors contributing to household transmission of COVID-19-using data from active epidemiological investigations performed in the Setagaya ward of Tokyo, Japan. Jpn J Infect Dis 2024:JJID.2023.342. [PMID: 38945861 DOI: 10.7883/yoken.jjid.2023.342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
An active epidemiological investigation of COVID-19 cases in the Setagaya ward of Tokyo revealed that household transmission was the main route of infection spread. This study aimed to identify the factors affecting household transmission in patients diagnosed with COVID-19 and their cohabitants, during the wild type virus (December 2020) and alpha variant epidemic (May 2021). Index case factors significantly associated with household transmission for both wild type (WT) and alpha variant (AV), were at least 3 days from onset to diagnosis (WT: risk ratio [RR] 1.44, 95% confidence interval [CI] 1.16-1.79/AV: RR 1.66, CI 1.32-2.08), and a household size of three or more people (WT: RR 1.37, CI 1.10-1.72/AV: RR 1.29, CI 1.05-1.59). There were also significant differences in age ≥ 65 (RR 2.39, CI 1.26-4.54) and symptomatic at diagnosis (RR 3.05, CI 1.22-7.63) in index cases of WT. Among cohabitants, factors associated with household transmission for both strains were being the spouse/partner of the index case (WT: RR 1.68, CI 1.21-1.82/AV: RR 1.97, CI 1.59-2.43) and at least 3 days from onset to diagnosis of the index case (WT: RR 1.48, CI 1.34-2.10/ AV: RR 1.86, CI1.52-2.28). Early diagnosis and isolation are effective for preventing household transmission.
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Affiliation(s)
- Mutsumi Kadowaki
- Department of Global Health Research, Graduate School of Medicine, Juntendo University, Japan
| | - Keiko Yasuoka
- Health Policy Division, Bureau of Public Health, Tokyo Metropolitan Government, Japan
| | | | | | - Yoshihisa Shirayama
- Department of Global Health Research, Graduate School of Medicine, Juntendo University, Japan
| | - Motoyuki Yuasa
- Department of Global Health Research, Graduate School of Medicine, Juntendo University, Japan
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Soriano López J, Gómez Gómez JH, Ballesta-Ruiz M, Garcia-Pina R, Sánchez-Rodríguez I, Bonilla-Escobar BA, Salmerón D, Rodríguez BS, Chirlaque MD. COVID-19, social determinants of transmission in the home. A population-based study. Eur J Public Health 2024; 34:427-434. [PMID: 38396184 PMCID: PMC11161145 DOI: 10.1093/eurpub/ckae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Studying transmission within the home is essential to understand the transmission dynamics of numerous infectious diseases. For Coronavirus Disease-2019 (COVID-19), transmission within the home constitutes the majority exposure context. The risk of infection in this setting can be quantified by the household/intra-family secondary attack rate (SAR). In the literature, there are discrepancies in these values and little information about its social determinants. The aim of this study was to investigate transmission in the home by analyzing the influence of occupational social class, country of origin and gender/sex. METHODS This was a retrospective cohort study of a population registry of cohabiting contacts with COVID-19 cases diagnosed from 15 June to 23 December 2020, in the Murcia Region. The household SAR was analyzed considering the characteristics of the primary case (sex, age, symptoms, occupational social class, country of origin and number of people in the household) and contact (age and sex) using a multilevel binary logistic regression model. RESULTS Among the 37 727 contacts included, the intra-family SAR was 39.1%. The contacts of confirmed primary cases in the migrant population (Africa and Latin America) had higher attack rates, even after adjusting for the other variables. Older age and female sex were independent risk factors for contracting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) within the home. CONCLUSION There was greater intra-domiciliary transmission among immigrants, likely related to the conditions of the home and situation of social vulnerability. Women were more likely to be infected by transmission from a cohabiting infected individual.
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Affiliation(s)
- Jesús Soriano López
- Murcia Region Health Department, Murcia, Spain
- Teaching Unit of Preventive Medicine and Public Health, Murcia, Spain
| | - Jesús Humberto Gómez Gómez
- Murcia Region Health Department, Murcia, Spain
- Department of Epidemiology, Murcia, Spain
- CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- IMIB Arrixaca, Murcia, Spain
| | - Monica Ballesta-Ruiz
- Murcia Region Health Department, Murcia, Spain
- Department of Epidemiology, Murcia, Spain
- IMIB Arrixaca, Murcia, Spain
- Division of Preventive Medicine and Public Health, Department of Public Health Sciences, University of Murcia, Murcia, Spain
| | - Rocio Garcia-Pina
- Murcia Region Health Department, Murcia, Spain
- Planning and Health Financing Department, Murcia, Spain
| | - Inés Sánchez-Rodríguez
- Murcia Region Health Department, Murcia, Spain
- Department of Epidemiology, Murcia, Spain
- IMIB Arrixaca, Murcia, Spain
| | - Bertha A Bonilla-Escobar
- Government of Spain Ministry of Health, Health Promotion and Equity Area, Deputy Directorate General for Health Promotion and Prevention, Directorate General for Public Madrid, Comunidad de Madrid, Madrid, Spain
- TRAGSATEC, Management of Health, Food Safety and Public Health Madrid, Comunidad de Madrid, Madrid, Spain
| | - Diego Salmerón
- CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- IMIB Arrixaca, Murcia, Spain
- Department of Health & Social Sciences, University of Murcia, Murcia, Spain
| | - Berta Suárez Rodríguez
- CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Government of Spain Ministry of Health, Spain Centre for Health Alerts and Emergencies, Directorate General of Public Health, Ministry of Health Madrid, Comunidad de Madrid, Madrid, Spain
| | - Maria-Dolores Chirlaque
- Murcia Region Health Department, Murcia, Spain
- Department of Epidemiology, Murcia, Spain
- CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- IMIB Arrixaca, Murcia, Spain
- Division of Preventive Medicine and Public Health, Department of Public Health Sciences, University of Murcia, Murcia, Spain
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Muhsen K, Waight PA, Kirsebom F, Andrews N, Letley L, Gower CM, Skarnes C, Quinot C, Lunt R, Bernal JL, Flasche S, Miller E. Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England. Vaccines (Basel) 2024; 12:113. [PMID: 38400097 PMCID: PMC10892628 DOI: 10.3390/vaccines12020113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/07/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND We investigated whether COVID-19 vaccination reduced SARS-CoV-2 infection risk among adult household contacts of COVID-19 index cases during the Alpha, Delta, and Omicron waves in England. METHODS Between February 2021 and February 2022, SARS-CoV-2 RT-PCR nasal swabs were collected from COVID-19-confirmed index cases aged ≥20 years and their household contacts at enrolment and three and seven days thereafter. Generalized Estimating Equations models were fitted with SARS-CoV-2 positivity as the outcome and household contacts' vaccination status as the main exposure while adjusting for confounders. RESULTS SARS-CoV-2 infection was confirmed in 238/472 household contacts (50.4%) aged ≥20 years. The adjusted relative risk (95% confidence interval) of infection in vaccinated versus unvaccinated household contacts was 0.50 (0.35-0.72) and 0.69 (0.53-0.90) for receipt of two doses 8-90 and >90 days ago, respectively, and 0.34 (0.23-0.50) for vaccination with three doses 8-151 days ago. Primary vaccination protected household contacts against infection during the Alpha and Delta waves, but only three doses protected during the Omicron wave. Vaccination with three doses in the index case independently reduced contacts' infection risk: 0.45 (0.23-0.89). CONCLUSIONS Vaccination of household contacts reduces their risk of infection under conditions of household exposure though, for Omicron, only after a booster dose.
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Affiliation(s)
- Khitam Muhsen
- Department of Epidemiology and Preventive Medicine, School of Public Health, Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (S.F.); (E.M.)
| | - Pauline A. Waight
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Freja Kirsebom
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Nick Andrews
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Louise Letley
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Charlotte M. Gower
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Catriona Skarnes
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Catherine Quinot
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Rachel Lunt
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
| | - Jamie Lopez Bernal
- UK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UK; (P.A.W.); (F.K.); (N.A.); (C.S.); (J.L.B.)
- NIHR Health Protection Research Unit in Respiratory Infections, Imperial College London, London SW7 2AZ, UK
| | - Stefan Flasche
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (S.F.); (E.M.)
| | - Elizabeth Miller
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (S.F.); (E.M.)
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Islam F, Alvi Y, Ahmad M, Ahmed F, Rahman A, Singh FHD, Das AK, Dudeja M, Gupta E, Agarwalla R, Alam I, Roy S. Household transmission dynamics of COVID-19 among residents of Delhi, India: a prospective case-ascertained study. IJID REGIONS 2023; 7:22-30. [PMID: 36852156 PMCID: PMC9946776 DOI: 10.1016/j.ijregi.2023.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023]
Abstract
Objective The aim of this study was to observe the secondary infection rate and transmission dynamics of COVID-19 among household contacts, and their associations with various factors across four dimensions of interaction. Methods This was a case-ascertained study among unvaccinated household contacts of a laboratory-confirmed COVID-19 case in New Delhi between December 2020 and July 2021. For this study, 99 index cases and their 316 household contacts were interviewed and sampled (blood and oro-nasal swab) on days 1, 7, 14, and 28. Results The secondary infection rate among unvaccinated household contacts was 44.6% (95% confidence interval (CI) 39.1-50.1). The predictors of secondary infection among individual contact levels were: being female (odds ratio (OR) 2.13), increasing age (OR 1.01), symptoms at baseline (OR 3.39), and symptoms during follow-up (OR 3.18). Among index cases, age of the primary case (OR 1.03) and symptoms during follow-up (OR 6.29) were significantly associated with secondary infection. Among household-level and contact patterns, having more rooms (OR 4.44) and taking care of the index case (OR 2.02) were significantly associated with secondary infection. Conclusion A high secondary infection rate highlights the need to adopt strict measures and advocate COVID-19-appropriate behaviors. A targeted approach for higher-risk household contacts would efficiently limit infections among susceptible contacts.
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Affiliation(s)
- Farzana Islam
- Department of Community Medicine, Hamdard Institute of Medical Science and Research, New Delhi, India
| | - Yasir Alvi
- Department of Community Medicine, Hamdard Institute of Medical Science and Research, New Delhi, India
| | | | - Faheem Ahmed
- Department of Community Medicine, Hamdard Institute of Medical Science and Research, New Delhi, India.,Department of Public Health, King Khalid University, Abha, Kingdom of Saudi Arabia
| | | | - Farishta Hannah D Singh
- Department of Community Medicine, Hamdard Institute of Medical Science and Research, New Delhi, India
| | - Ayan Kumar Das
- Department of Microbiology, Hamdard Institute of Medical Science and Research, New Delhi, India
| | - Mridu Dudeja
- Department of Microbiology, Hamdard Institute of Medical Science and Research, New Delhi, India
| | - Ekta Gupta
- Scientist-E, National Institute of Cancer Prevention and Research, ICMR, Noida, India
| | - Rashmi Agarwalla
- Department of Community and Family Medicine, All India Institute of Medical Science, Guwahati, India
| | - Iqbal Alam
- Department of Physiology, Hamdard Institute of Medical Science and Research, New Delhi, India
| | - Sushovan Roy
- Department of Community Medicine, Hamdard Institute of Medical Science and Research, New Delhi, India
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Martínez-Baz I, Miqueleiz A, Egüés N, Casado I, Burgui C, Echeverría A, Navascués A, Fernández-Huerta M, García Cenoz M, Trobajo-Sanmartín C, Guevara M, Ezpeleta C, Castilla J. Effect of COVID-19 vaccination on the SARS-CoV-2 transmission among social and household close contacts: A cohort study. J Infect Public Health 2023; 16:410-417. [PMID: 36724697 PMCID: PMC9876028 DOI: 10.1016/j.jiph.2023.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND COVID-19 vaccination was expected to reduce SARS-CoV-2 transmission, but the relevance of this effect remains unclear. We aimed to estimate the effectiveness of COVID-19 vaccination of the index cases and their close contacts in reducing the probability of SARS-CoV-2 transmission. METHODS Transmission of SARS-CoV-2 infection was evaluated in two cohorts of adult close contacts of COVID-19 confirmed cases (social and household settings) by COVID-19 vaccination status of the index case and the close contact, from April to November 2021 in Navarre, Spain. The effects of vaccination of the index case and the close contact were estimated as (1-adjusted relative risk) × 100%. RESULTS Among 19,631 social contacts, 3257 (17%) were confirmed with SARS-CoV-2. COVID-19 vaccination of the index case reduced infectiousness by 44% (95% CI, 27-57%), vaccination of the close contact reduced susceptibility by 69% (95% CI, 65-73%), and vaccination of both reduced transmissibility by 74% (95% CI, 70-78%) in social settings, suggesting some synergy of effects. Among 20,708 household contacts, 6269 (30%) were infected, and vaccine effectiveness estimates were 13% (95% CI, -5% to 28%), 61% (95% CI, 58-64%), and 52% (95% CI, 47-56%), respectively. These estimates were lower in older people and had not relevant differences between the Alpha (April-June) and Delta (July-November) variant periods. CONCLUSIONS COVID-19 vaccination reduces infectiousness and susceptibility; however, these effects are insufficient for complete control of SARS-CoV-2 transmission, especially in older people and household setting. Relaxation of preventive behaviors after vaccination may counteract part of the vaccine effect on transmission.
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Affiliation(s)
- Iván Martínez-Baz
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Ana Miqueleiz
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain,Clinical Microbiology Department, Hospital Universitario de Navarra, Irunlarrea, 31008 Pamplona, Spain
| | - Nerea Egüés
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Itziar Casado
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Cristina Burgui
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | | | - Ana Navascués
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain,Clinical Microbiology Department, Hospital Universitario de Navarra, Irunlarrea, 31008 Pamplona, Spain
| | - Miguel Fernández-Huerta
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain,Clinical Microbiology Department, Hospital Universitario de Navarra, Irunlarrea, 31008 Pamplona, Spain
| | - Manuel García Cenoz
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Camino Trobajo-Sanmartín
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Marcela Guevara
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain,CIBER Epidemiología y Salud Pública, Pamplona, Spain,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Carmen Ezpeleta
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain,Clinical Microbiology Department, Hospital Universitario de Navarra, Irunlarrea, 31008 Pamplona, Spain
| | - Jesús Castilla
- Instituto de Salud Pública de Navarra, Leyre 15, 31003 Pamplona, Spain; CIBER Epidemiología y Salud Pública, Pamplona, Spain; Navarra Institute for Health Research (IdiSNA), Pamplona, Spain.
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Wang C, Huang X, Lau EHY, Cowling BJ, Tsang TK. Association Between Population-Level Factors and Household Secondary Attack Rate of SARS-CoV-2: A Systematic Review and Meta-analysis. Open Forum Infect Dis 2022; 10:ofac676. [PMID: 36655186 PMCID: PMC9835764 DOI: 10.1093/ofid/ofac676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Background Accurate estimation of household secondary attack rate (SAR) is crucial to understand the transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The impact of population-level factors, such as transmission intensity in the community, on SAR estimates is rarely explored. Methods In this study, we included articles with original data to compute the household SAR. To determine the impact of transmission intensity in the community on household SAR estimates, we explored the association between SAR estimates and the incidence rate of cases by country during the study period. Results We identified 163 studies to extract data on SARs from 326 031 cases and 2 009 859 household contacts. The correlation between the incidence rate of cases during the study period and SAR estimates was 0.37 (95% CI, 0.24-0.49). We found that doubling the incidence rate of cases during the study period was associated with a 1.2% (95% CI, 0.5%-1.8%) higher household SAR. Conclusions Our findings suggest that the incidence rate of cases during the study period is associated with higher SAR. Ignoring this factor may overestimate SARs, especially for regions with high incidences, which further impacts control policies and epidemiological characterization of emerging variants.
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Affiliation(s)
- Can Wang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Xiaotong Huang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eric H Y Lau
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Tim K Tsang
- Correspondence: Tim K. Tsang, PhD, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 7 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, China ()
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Areekal B, Joseph NC, Rajan MP, Ravindran RK, Vijayan AS, Vanlalhriatpuii E. Household secondary attack rate in SARS-CoV-2 infection during the second wave of the COVID-19 pandemic in South India. J Family Med Prim Care 2022; 11:6268-6273. [PMID: 36618242 PMCID: PMC9810882 DOI: 10.4103/jfmpc.jfmpc_452_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 11/11/2022] Open
Abstract
Background Coronavirus disease 2019 (COVID-19) has become a major public health problem since its inception disrupting public life and crippling health systems. The mutated variant of the causative virus, Delta, has been notorious in causing rapid upsurge in cases compared to the Alpha variant. The current study tries to find out the household secondary attack rate (HSAR) of COVID-19 and factors associated with it during the second wave of cases in Kerala. Methodology A retrospective cohort study was performed among 313 household contacts of 76 COVID-19 patients who had been admitted in Government Medical College, Thrissur, in the southern state of India, Kerala. Data from the participants were collected via phone using a semi-structured interview schedule, and analysis was performed with SPSS software. Results The HSAR among household contacts was 59.1% (53.4-64.6%). The risk of acquiring COVID infection among household contacts was higher among contacts of symptomatic index cases with a P value of 0.001 and an odds ratio of 11 (3.7-32.4). index cases were having a home isolation P value of 0.001 and an odds ratio of 3.2 (2-5.1), with delay in COVID-19 testing for index cases with a P value of 0.006. Regarding characteristics of household contacts, higher age groups (p = 0.048), groups living in the same room with an index case P value of 0.021 and an odds ratio of [1.71 (1-2.8)], groups having physical contact with an index case P value of 0.001 and an odds ratio of [3.7 (2.1-7)], groups with touched or cleaned linen/articles with an index case P value of 0.02 and an odds ratio of [1.8 (1-3.1)], and groups having co-morbidities, especially diabetes mellitus (p = 0.0020), were significantly associated with chances of acquiring infection. However, the history of previous COVID positivity in household contacts was a protective factor against the infection P value of 0.009 with an odds ratio of [0.09 (0.01-0.78)]. Conclusion The study concludes that the second wave of COVID-19 in Kerala was primarily caused by a high SAR, especially among household contacts, and this could have been the reason for the difficulty in control measures during the wave.
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Affiliation(s)
- Binu Areekal
- Department of Community Medicine, Government Medical College, Thrissur, Kerala, India,Address for correspondence: Dr. Binu Areekal, Department of Community Medicine, Government Medical College, Thrissur, Kerala, India. E-mail:
| | - Navya C. Joseph
- Department of Community Medicine, Government Medical College, Thrissur, Kerala, India
| | - Maneesha P. Rajan
- Department of Community Medicine, Government Medical College, Thrissur, Kerala, India
| | - Reshmy K. Ravindran
- Department of Community Medicine, Government Medical College, Thrissur, Kerala, India
| | - Anagha S. Vijayan
- Department of Community Medicine, Government Medical College, Thrissur, Kerala, India
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Chen F, Tian Y, Zhang L, Shi Y. The role of children in household transmission of COVID-19: a systematic review and meta-analysis. Int J Infect Dis 2022; 122:266-275. [PMID: 35562045 PMCID: PMC9091150 DOI: 10.1016/j.ijid.2022.05.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVES To explore household transmissibility of SARS-CoV-2 in children in new-variants dominating periods. METHODS Through retrieval in PubMed and Embase, studies were included in two parts: meta-analysis of the household secondary attack rate (SAR) and case analysis of household pediatric infections. RESULTS A total of 95 articles were included: 48 for meta-analysis and 47 for case analysis. Pediatric COVID-19 only comprised a minority of the household transmission. The total pooled household SAR of child index cases and contacts were 0.20 (95% confidence interval [CI]: 0.15-0.26) and 0.24 (95% CI: 0.18-0.30). Lower household transmissibility was reported in both child index cases and contacts than in adults (relative risk [RR] = 0.64, 95% CI: 0.50-0.81; RR = 0.74, 95% CI: 0.64-0.85). Younger children were as susceptible as the older children (RR = 0.89, 95% CI: 0.72-1.10). Through subgroup analyses of different variants and periods, increased household SAR was observed in children (Wild: 0.20; Alpha: 0.42; Delta: 0.35; Omicron: 0.56), and no significant difference was found in household SAR between children and adults when new variants dominated. CONCLUSION Although children were found not to be dominant in the household transmission, their transmissibility of SARS-CoV-2 appeared to be on the rise as new variants emerged.
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Affiliation(s)
| | | | | | - Yuan Shi
- Corresponding author: Yuan Shi, Children's Hospital of Chongqing Medical University, Chongqing 400014, China, Mob: 00862363635678
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Ogata T, Tanaka H, Irie F, Nozawa Y, Noguchi E, Seo K, Tanaka E. A low proportion of asymptomatic COVID-19 patients with the Delta variant infection by viral transmission through household contact at the time of confirmation in Ibaraki, Japan. Glob Health Med 2022; 4:192-196. [PMID: 35855062 PMCID: PMC9243404 DOI: 10.35772/ghm.2021.01116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/20/2022] [Accepted: 02/26/2022] [Indexed: 06/15/2023]
Abstract
We conducted a study to investigate the proportion of patients with asymptomatic coronavirus disease 2019 (COVID-19) infected with the Delta variant compared with those infected with the wild-type strain at the time of confirmation. A total of 504 patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by viral transmission through household contact in Ibaraki, Japan were included. The proportion of asymptomatic COVID-19 patients at the time of confirmation was compared between patients infected with L452R mutation strain from June to September 2021 and those infected with the wild-type strain from November 2020 to January 2021, and was found to be 14.2% and 28.8%, respectively (relative risk, 0.49; 95% confidence interval, 0.35-0.70). The proportion of asymptomatic COVID-19 patients by viral transmission through household contact was lower among the Delta variant than those among the wild-type strain at the time of confirmation. It might contribute to attenuation of transmission.
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Affiliation(s)
- Tsuyoshi Ogata
- Itako Public Health Center of Ibaraki Prefectural Government, Itako, Japan
| | - Hideo Tanaka
- Fujiidera Public Health Center of Osaka Prefectural Government, Fujiidera, Japan
| | - Fujiko Irie
- Tsuchiura Public Health Center of Ibaraki Prefectural Government, Tsuchiura, Japan
| | - Yumiko Nozawa
- Itako Public Health Center of Ibaraki Prefectural Government, Itako, Japan
| | - Etsuko Noguchi
- Itako Public Health Center of Ibaraki Prefectural Government, Itako, Japan
| | - Kayoko Seo
- Itako Public Health Center of Ibaraki Prefectural Government, Itako, Japan
| | - Emiko Tanaka
- Itako Public Health Center of Ibaraki Prefectural Government, Itako, Japan
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Ogata T, Tanaka H, Tanaka E, Osaki N, Noguchi E, Osaki Y, Tono A, Wada K. Increased Secondary Attack Rates among the Household Contacts of Patients with the Omicron Variant of the Coronavirus Disease 2019 in Japan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19138068. [PMID: 35805724 PMCID: PMC9266248 DOI: 10.3390/ijerph19138068] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 12/13/2022]
Abstract
This study investigated the household secondary attack rate (HSAR) of patients with coronavirus disease (COVID-19) during the omicron variant-dominant period. The HSAR of COVID-19 cases during the omicron variant-dominant period (4–20 January 2022) was calculated and compared with the delta variant-dominant period (20 August to 7 November 2021) in Itako, Japan. In Itako, all 47 and 119 samples tested during the omicron and delta variant-dominant periods were negative and positive, respectively, for the L452R mutation. We used a generalized estimating equation regression model. The HSAR was 31.8% (95% confidence interval (CI) 27.7–36.2) for 456 household contacts during the omicron variant-dominant period; it was higher than that during the delta variant-dominant period (25.2%) (adjusted risk ratio [aRR] 1.61, CI 1.13–2.28). During the omicron variant-dominant period, HSAR was lower for the household contacts of completely vaccinated index patients (27.3%) than for contacts of other index patients (41.2%) (vaccine effectiveness for infectee 0.43, 95% CI 0.16–0.62) and was significantly higher for female contacts than for male contacts (36.2% vs. 26.1%; aRR 1.29, 95% CI 1.01–1.65). The HSAR was significantly higher during the omicron variant-dominant period than the delta variant-dominant period. The vaccination of index patients might protect household contacts.
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Affiliation(s)
- Tsuyoshi Ogata
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
- Correspondence:
| | - Hideo Tanaka
- Public Health Center of Neyagawa City Government, Neyagawa 572-0838, Japan;
| | - Emiko Tanaka
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
| | - Natsumi Osaki
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
| | - Etsuko Noguchi
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
| | - Yukino Osaki
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
| | - Ayane Tono
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (E.T.); (N.O.); (E.N.); (Y.O.); (A.T.)
| | - Koji Wada
- Department of Public Health, Faculty of Medicine, International University of Health and Welfare, Tokyo 107-8402, Japan;
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Madewell ZJ, Yang Y, Longini IM, Halloran ME, Dean NE. Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status: An Updated Systematic Review and Meta-analysis. JAMA Netw Open 2022; 5:e229317. [PMID: 35482308 PMCID: PMC9051991 DOI: 10.1001/jamanetworkopen.2022.9317] [Citation(s) in RCA: 114] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
IMPORTANCE An overall household secondary attack rate (SAR) of 18.9% (95% CI, 16.2%-22.0%) through June 17, 2021 was previously reported for SARS-CoV-2. Emerging variants of concern and increased vaccination have affected transmission rates. OBJECTIVE To evaluate how reported household SARs changed over time and whether SARs varied by viral variant and index case and contact vaccination status. DATA SOURCES PubMed and medRxiv from June 18, 2021, through March 8, 2022, and reference lists of eligible articles. Preprints were included. STUDY SELECTION Articles with original data reporting the number of infected and total number of household contacts. Search terms included SARS-CoV-2, COVID-19, variant, vaccination, secondary attack rate, secondary infection rate, household, index case, family contacts, close contacts, and family transmission. DATA EXTRACTION AND SYNTHESIS The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline was followed. Meta-analyses used generalized linear mixed models to obtain SAR estimates and 95% CIs. MAIN OUTCOMES AND MEASURES SAR stratified by covariates according to variant, index case and contact vaccination status, and index case identification period. SARs were used to estimate vaccine effectiveness on the basis of the transmission probability for susceptibility to infection (VES,p), infectiousness given infection (VEI,p), and total vaccine effectiveness (VET,p). RESULTS Household SARs were higher for 33 studies with midpoints in 2021 to 2022 (37.3%; 95% CI, 32.7% to 42.1%) compared with 63 studies with midpoints through April 2020 (15.5%; 95% CI, 13.2% to 18.2%). Household SARs were 42.7% (95% CI, 35.4% to 50.4%) for Omicron (7 studies), 36.4% (95% CI, 33.4% to 39.5%) for Alpha (11 studies), 29.7% (95% CI, 23.0% to 37.3%) for Delta (16 studies), and 22.5% (95% CI, 18.6% to 26.8%) for Beta (3 studies). For full vaccination, VES,p was 78.6% (95% CI, 76.0% to 80.9%) for Alpha, 56.4% (95% CI, 54.6% to 58.1%) for Delta, and 18.1% (95% CI, -18.3% to 43.3%) for Omicron; VEI,p was 75.3% (95% CI, 69.9% to 79.8%) for Alpha, 21.9% (95% CI, 11.0% to 31.5%) for Delta, and 18.2% (95% CI, 0.6% to 32.6%) for Omicron; and VET,p was 94.7% (95% CI, 93.3% to 95.8%) for Alpha, 64.4% (95% CI, 58.0% to 69.8%) for Delta, and 35.8% (95% CI, 13.0% to 52.6%) for Omicron. CONCLUSIONS AND RELEVANCE These results suggest that emerging SARS-CoV-2 variants of concern have increased transmissibility. Full vaccination was associated with reductions in susceptibility and infectiousness, but more so for Alpha than Delta and Omicron. The changes in estimated vaccine effectiveness underscore the challenges of developing effective vaccines concomitant with viral evolution.
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Affiliation(s)
| | - Yang Yang
- Department of Biostatistics, University of Florida, Gainesville
| | - Ira M. Longini
- Department of Biostatistics, University of Florida, Gainesville
| | - M. Elizabeth Halloran
- Fred Hutchinson Cancer Research Center, Seattle, Washington
- Department of Biostatistics, University of Washington, Seattle
| | - Natalie E. Dean
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, Georgia
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12
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Ogata T, Tanaka H, Nozawa Y, Mukouyama K, Tanaka E, Osaki N, Noguchi E, Seo K, Wada K. Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19073889. [PMID: 35409572 PMCID: PMC8997792 DOI: 10.3390/ijerph19073889] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/15/2022] [Accepted: 03/21/2022] [Indexed: 02/06/2023]
Abstract
This study aimed to elucidate the household secondary attack rate (HSAR) of the Delta variant in comparison to the Alpha variant, and evaluate the risk factors among unvaccinated household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index cases of COVID-19 infected with Delta (L452R mutation), Alpha (N501Y mutation), and wild strain from December 2020 through November 2021 in Itako, Japan. The HSARs of the entire household contact, and the contact of index case with Delta variant were calculated and compared across the risk factors. We used a generalized estimating equation regression model for the multivariate analysis. We enrolled 1257 unvaccinated contacts from 580 households. The HSAR was higher in household contacts of index patients with Delta (48.5%) than with Alpha variant (21.7%) (aOR = 3.34, p = 0.000). In Delta variants, the HSAR was higher in household contacts with spousal relationships to index patients (63.4%) than contacts with other relationships (45.5%) (aOR 1.94, p = 0.026), and was lower in household contacts of index patients aged ≤19 (33.1%) than for contacts of index cases aged 20–59 years (52.6%) (aOR = 0.50, p = 0.027). The result of our study can be used to devise informed strategy to prevent transmission within households.
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Affiliation(s)
- Tsuyoshi Ogata
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
- Correspondence:
| | - Hideo Tanaka
- Fujiidera Public Health Center of Osaka Prefectural Government, Fujiidera 583-0024, Japan;
| | - Yumiko Nozawa
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Kazue Mukouyama
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Emiko Tanaka
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Natsumi Osaki
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Etsuko Noguchi
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Kayoko Seo
- Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan; (Y.N.); (K.M.); (E.T.); (N.O.); (E.N.); (K.S.)
| | - Koji Wada
- Department of Public Health, Faculty of Medicine and Graduate School of Public Health, International University of Health and Welfare, Tokyo 107-8402, Japan;
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Martínez-Baz I, Trobajo-Sanmartín C, Burgui C, Casado I, Castilla J. Transmission of SARS-CoV-2 infection and risk factors in a cohort of close contacts. Postgrad Med 2022; 134:230-238. [PMID: 35102793 DOI: 10.1080/00325481.2022.2037360] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE Many factors might affect SARS-CoV-2 transmission, but their relevance is not well established. The objectives were to assess the secondary attack rate (SAR) and the risk factors for SARS-CoV-2 transmission from confirmed index cases to their close contacts in household and non-household settings. METHODS This cohort study included the close contacts of SARS-CoV-2 infected cases confirmed between May and December 2020 in Navarre, Spain. Epidemiological and clinical variables of the index case and close contacts were collected. The SAR was calculated, and the independent effect of each variable on the transmission risk was evaluated by logistic regression. RESULTS A total of 59,900 close contacts of 20,048 index cases were studied, and 53.6% were household contacts. SAR was 34.9% overall, 46.8% in household contacts and 21.1% in non-household contacts. The risk of transmission was higher in household setting (adjusted odds ratio (aOR) 2.96, 95% CI 2.84-3.07), from symptomatic index cases (aOR 1.50, 95% CI 1.43-1.58), immigrants (aOR 1.44, 95% CI 1.36-1.52), and increased with age. A higher susceptibility of close contacts was associated with 5-14 years of age, immigrants (aOR 1.54), very low or low-income level (aOR 1.27, and aOR, 1.17, respectively), healthcare work (aOR 1.21), and diagnosis of diabetes (aOR 1.14, 95%CI 1.03-1.25), chronic kidney disease (aOR 1.18, 95%CI 1.04-1.35), hypertension (aOR 1.11, 95% CI 1.03-1.19), and severe obesity (aOR 1.18, 95% CI 1.00-1.38). Transmission increased progressively from May to September 2020 as the B.1.177 variant became dominant. CONCLUSION The risk of SARS-CoV-2 infection was considerable among close contacts of infected persons. The higher risk associated with household contacts, immigrants, older index cases, close contacts with lower income level and comorbidities should be considered to address preventive interventions.
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Affiliation(s)
- Iván Martínez-Baz
- Instituto de Salud Pública de Navarra, Pamplona, Spain.,Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Pamplona, Spain
| | - Camino Trobajo-Sanmartín
- Instituto de Salud Pública de Navarra, Pamplona, Spain.,Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Pamplona, Spain
| | - Cristina Burgui
- Instituto de Salud Pública de Navarra, Pamplona, Spain.,Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Pamplona, Spain
| | - Itziar Casado
- Instituto de Salud Pública de Navarra, Pamplona, Spain.,Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Pamplona, Spain
| | - Jesús Castilla
- Instituto de Salud Pública de Navarra, Pamplona, Spain.,Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Pamplona, Spain
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Madewell ZJ, Yang Y, Longini IM, Halloran ME, Dean NE. Household secondary attack rates of SARS-CoV-2 by variant and vaccination status: an updated systematic review and meta-analysis. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2022:2022.01.09.22268984. [PMID: 35043125 PMCID: PMC8764734 DOI: 10.1101/2022.01.09.22268984] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We previously reported a household secondary attack rate (SAR) for SARS-CoV-2 of 18.9% through June 17, 2021. To examine how emerging variants and increased vaccination have affected transmission rates, we searched PubMed from June 18, 2021, through January 7, 2022. Meta-analyses used generalized linear mixed models to obtain SAR estimates and 95%CI, disaggregated by several covariates. SARs were used to estimate vaccine effectiveness based on the transmission probability for susceptibility ( VE S,p ), infectiousness ( VE I,p ), and total vaccine effectiveness ( VE T,p ). Household SAR for 27 studies with midpoints in 2021 was 35.8% (95%CI, 30.6%-41.3%), compared to 15.7% (95%CI, 13.3%-18.4%) for 62 studies with midpoints through April 2020. Household SARs were 38.0% (95%CI, 36.0%-40.0%), 30.8% (95%CI, 23.5%-39.3%), and 22.5% (95%CI, 18.6%-26.8%) for Alpha, Delta, and Beta, respectively. VE I,p , VE S,p , and VE T,p were 56.6% (95%CI, 28.7%-73.6%), 70.3% (95%CI, 59.3%-78.4%), and 86.8% (95%CI, 76.7%-92.5%) for full vaccination, and 27.5% (95%CI, -6.4%-50.7%), 43.9% (95%CI, 21.8%-59.7%), and 59.9% (95%CI, 34.4%-75.5%) for partial vaccination, respectively. Household contacts exposed to Alpha or Delta are at increased risk of infection compared to the original wild-type strain. Vaccination reduced susceptibility to infection and transmission to others. SUMMARY Household secondary attack rates (SARs) were higher for Alpha and Delta variants than previous estimates. SARs were higher to unvaccinated contacts than to partially or fully vaccinated contacts and were higher from unvaccinated index cases than from fully vaccinated index cases.
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Affiliation(s)
| | - Yang Yang
- Department of Biostatistics, University of Florida, Gainesville, FL
| | - Ira M. Longini
- Department of Biostatistics, University of Florida, Gainesville, FL
| | - M. Elizabeth Halloran
- Fred Hutchinson Cancer Research Center, Seattle, WA
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Natalie E. Dean
- Department of Biostatistics, University of Florida, Gainesville, FL
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