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Lyngse FP, Kirkeby CT, Denwood M, Christiansen LE, Mølbak K, Møller CH, Skov RL, Krause TG, Rasmussen M, Sieber RN, Johannesen TB, Lillebaek T, Fonager J, Fomsgaard A, Møller FT, Stegger M, Overvad M, Spiess K, Mortensen LH. Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark. Nat Commun 2022. [PMID: 36180438 DOI: 10.1101/2022.01.28.22270044] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1-7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%-CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%-CI 1.95-2.62) and booster-vaccinated contacts (OR 2.65; 95%-CI 2.29-3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%-CI 2.15-2.84), but not for fully vaccinated (OR 0.66; 95%-CI 0.57-0.78) or booster-vaccinated primary cases (OR 0.69; 95%-CI 0.59-0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behavior and Inequality, University of Copenhagen, Copenhagen, Denmark.
- Danish Ministry of Health, Copenhagen, Denmark.
- Statens Serum Institut, Copenhagen, Denmark.
| | - Carsten Thure Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Engbo Christiansen
- Department of Applied Mathematics and Computer Science; Dynamical Systems, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Kåre Mølbak
- Statens Serum Institut, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Troels Lillebaek
- Statens Serum Institut, Copenhagen, Denmark
- Global Health Section, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Laust Hvas Mortensen
- Statistics Denmark, Copenhagen, Denmark
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Lyngse FP, Kirkeby CT, Denwood M, Christiansen LE, Mølbak K, Møller CH, Skov RL, Krause TG, Rasmussen M, Sieber RN, Johannesen TB, Lillebaek T, Fonager J, Fomsgaard A, Møller FT, Stegger M, Overvad M, Spiess K, Mortensen LH. Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark. Nat Commun 2022; 13:5760. [PMID: 36180438 PMCID: PMC9524324 DOI: 10.1038/s41467-022-33498-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/16/2022] [Indexed: 12/12/2022] Open
Abstract
SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1–7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%–CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%–CI 1.95–2.62) and booster-vaccinated contacts (OR 2.65; 95%–CI 2.29–3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%–CI 2.15–2.84), but not for fully vaccinated (OR 0.66; 95%–CI 0.57–0.78) or booster-vaccinated primary cases (OR 0.69; 95%–CI 0.59–0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals. In this study, the authors use household data from Denmark to investigate the transmissibility of the BA.1 and BA.2 Omicron SARS-CoV-2 subvariants. They find that the secondary attack rate was higher for BA.2, but that it had higher infectiousness only when cases were not vaccinated.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behavior and Inequality, University of Copenhagen, Copenhagen, Denmark. .,Danish Ministry of Health, Copenhagen, Denmark. .,Statens Serum Institut, Copenhagen, Denmark.
| | - Carsten Thure Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Engbo Christiansen
- Department of Applied Mathematics and Computer Science; Dynamical Systems, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Kåre Mølbak
- Statens Serum Institut, Copenhagen, Denmark.,Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Troels Lillebaek
- Statens Serum Institut, Copenhagen, Denmark.,Global Health Section, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Laust Hvas Mortensen
- Statistics Denmark, Copenhagen, Denmark.,Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Lyngse FP, Kirkeby CT, Denwood M, Christiansen LE, Mølbak K, Møller CH, Skov RL, Krause TG, Rasmussen M, Sieber RN, Johannesen TB, Lillebaek T, Fonager J, Fomsgaard A, Møller FT, Stegger M, Overvad M, Spiess K, Mortensen LH. Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark. Nat Commun 2022; 13:5760. [PMID: 36180438 DOI: 10.1101/2022.1101.1128.22270044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/16/2022] [Indexed: 05/23/2023] Open
Abstract
SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1-7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%-CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%-CI 1.95-2.62) and booster-vaccinated contacts (OR 2.65; 95%-CI 2.29-3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%-CI 2.15-2.84), but not for fully vaccinated (OR 0.66; 95%-CI 0.57-0.78) or booster-vaccinated primary cases (OR 0.69; 95%-CI 0.59-0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behavior and Inequality, University of Copenhagen, Copenhagen, Denmark.
- Danish Ministry of Health, Copenhagen, Denmark.
- Statens Serum Institut, Copenhagen, Denmark.
| | - Carsten Thure Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Engbo Christiansen
- Department of Applied Mathematics and Computer Science; Dynamical Systems, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Kåre Mølbak
- Statens Serum Institut, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Troels Lillebaek
- Statens Serum Institut, Copenhagen, Denmark
- Global Health Section, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | - Laust Hvas Mortensen
- Statistics Denmark, Copenhagen, Denmark
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Lyngse FP, Mortensen LH, Denwood MJ, Christiansen LE, Møller CH, Skov RL, Spiess K, Fomsgaard A, Lassaunière R, Rasmussen M, Stegger M, Nielsen C, Sieber RN, Cohen AS, Møller FT, Overvad M, Mølbak K, Krause TG, Kirkeby CT. Household transmission of the SARS-CoV-2 Omicron variant in Denmark. Nat Commun 2022; 13:5573. [PMID: 36151099 PMCID: PMC9508106 DOI: 10.1038/s41467-022-33328-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/13/2022] [Indexed: 01/07/2023] Open
Abstract
In late 2021, the Omicron SARS-CoV-2 variant overtook the previously dominant Delta variant, but the extent to which this transition was driven by immune evasion or a change in the inherent transmissibility is currently unclear. We estimate SARS-CoV-2 transmission within Danish households during December 2021. Among 26,675 households (8,568 with the Omicron VOC), we identified 14,140 secondary infections within a 1-7-day follow-up period. The secondary attack rate was 29% and 21% in households infected with Omicron and Delta, respectively. For Omicron, the odds of infection were 1.10 (95%-CI: 1.00-1.21) times higher for unvaccinated, 2.38 (95%-CI: 2.23-2.54) times higher for fully vaccinated and 3.20 (95%-CI: 2.67-3.83) times higher for booster-vaccinated contacts compared to Delta. We conclude that the transition from Delta to Omicron VOC was primarily driven by immune evasiveness and to a lesser extent an inherent increase in the basic transmissibility of the Omicron variant.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behavior and Inequality, University of Copenhagen, Øster Farimagsgade 5, DK-1353, Copenhagen K, Denmark. .,Danish Ministry of Health, Holbergsgade 6, DK-1057, Copenhagen K, Denmark. .,Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark.
| | - Laust Hvas Mortensen
- Statistics Denmark, Sejrøgade 11, DK-2100, Copenhagen, Denmark.,Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Øster Farimagsgade 5, DK-1353, Copenhagen K, Denmark
| | - Matthew J Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Copenhagen, Denmark
| | - Lasse Engbo Christiansen
- Department of Applied Mathematics and Computer Science, Dynamical Systems, Technical University of Denmark, Richard Petersens Plads, 324, DK-2800, Kgs. Lyngby, Denmark
| | | | - Robert Leo Skov
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Katja Spiess
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Anders Fomsgaard
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Ria Lassaunière
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Morten Rasmussen
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Marc Stegger
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Claus Nielsen
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Raphael Niklaus Sieber
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | | | | | - Maria Overvad
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Kåre Mølbak
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark.,Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Copenhagen, Denmark
| | - Tyra Grove Krause
- Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark
| | - Carsten Thure Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Copenhagen, Denmark
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5
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Lyngse FP, Kirkeby C, Halasa T, Andreasen V, Skov RL, Møller FT, Krause TG, Mølbak K. Nationwide study on SARS-CoV-2 transmission within households from lockdown to reopening, Denmark, 27 February 2020 to 1 August 2020. Euro Surveill 2022; 27. [PMID: 35144726 PMCID: PMC8832519 DOI: 10.2807/1560-7917.es.2022.27.6.2001800] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background The COVID-19 pandemic is one of the most serious global public health threats of recent times. Understanding SARS-CoV-2 transmission is key for outbreak response and to take action against the spread of disease. Transmission within the household is a concern, especially because infection control is difficult to apply within this setting. Aim The objective of this observational study was to investigate SARS-CoV-2 transmission in Danish households during the early stages of the COVID-19 pandemic. Methods We used comprehensive administrative register data from Denmark, comprising the full population and all COVID-19 tests from 27 February 2020 to 1 August 2020, to estimate household transmission risk and attack rate. Results We found that the day after receiving a positive test result within the household, 35% (788/2,226) of potential secondary cases were tested and 13% (98/779) of these were positive. In 6,782 households, we found that 82% (1,827/2,226) of potential secondary cases were tested within 14 days and 17% (371/2,226) tested positive as secondary cases, implying an attack rate of 17%. We found an approximate linear increasing relationship between age and attack rate. We investigated the transmission risk from primary cases by age, and found an increasing risk with age of primary cases for adults (aged ≥ 15 years), while the risk seems to decrease with age for children (aged < 15 years). Conclusions Although there is an increasing attack rate and transmission risk of SARS-CoV-2 with age, children are also able to transmit SARS-CoV-2 within the household.
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Affiliation(s)
- Frederik Plesner Lyngse
- Statens Serum Institut, Copenhagen, Denmark.,Danish Ministry of Health, Copenhagen, Denmark.,Department of Economics & Center for Economic Behaviour and Inequality, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tariq Halasa
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Viggo Andreasen
- Department of Science, Roskilde University, Roskilde, Denmark
| | | | | | | | - Kåre Mølbak
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Statens Serum Institut, Copenhagen, Denmark
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6
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Lyngse FP, Kirkeby C, Halasa T, Andreasen V, Skov RL, Møller FT, Krause TG, Mølbak K. Nationwide study on SARS-CoV-2 transmission within households from lockdown to reopening, Denmark, 27 February 2020 to 1 August 2020. Euro Surveill 2022. [PMID: 35144726 DOI: 10.1101/2020.09.09.20191239] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
BackgroundThe COVID-19 pandemic is one of the most serious global public health threats of recent times. Understanding SARS-CoV-2 transmission is key for outbreak response and to take action against the spread of disease. Transmission within the household is a concern, especially because infection control is difficult to apply within this setting.AimThe objective of this observational study was to investigate SARS-CoV-2 transmission in Danish households during the early stages of the COVID-19 pandemic.MethodsWe used comprehensive administrative register data from Denmark, comprising the full population and all COVID-19 tests from 27 February 2020 to 1 August 2020, to estimate household transmission risk and attack rate.ResultsWe found that the day after receiving a positive test result within the household, 35% (788/2,226) of potential secondary cases were tested and 13% (98/779) of these were positive. In 6,782 households, we found that 82% (1,827/2,226) of potential secondary cases were tested within 14 days and 17% (371/2,226) tested positive as secondary cases, implying an attack rate of 17%. We found an approximate linear increasing relationship between age and attack rate. We investigated the transmission risk from primary cases by age, and found an increasing risk with age of primary cases for adults (aged ≥ 15 years), while the risk seems to decrease with age for children (aged < 15 years).ConclusionsAlthough there is an increasing attack rate and transmission risk of SARS-CoV-2 with age, children are also able to transmit SARS-CoV-2 within the household.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behaviour and Inequality, University of Copenhagen, Copenhagen, Denmark
- Danish Ministry of Health, Copenhagen, Denmark
- Statens Serum Institut, Copenhagen, Denmark
| | - Carsten Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tariq Halasa
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Viggo Andreasen
- Department of Science, Roskilde University, Roskilde, Denmark
| | | | | | | | - Kåre Mølbak
- Statens Serum Institut, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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7
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Lyngse FP, Mølbak K, Skov RL, Christiansen LE, Mortensen LH, Albertsen M, Møller CH, Krause TG, Rasmussen M, Michaelsen TY, Voldstedlund M, Fonager J, Steenhard N, Kirkeby CT. Increased transmissibility of SARS-CoV-2 lineage B.1.1.7 by age and viral load. Nat Commun 2021; 12:7251. [PMID: 34903718 PMCID: PMC8669007 DOI: 10.1038/s41467-021-27202-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/08/2021] [Indexed: 01/03/2023] Open
Abstract
New lineages of SARS-CoV-2 are of potential concern due to higher transmissibility, risk of severe outcomes, and/or escape from neutralizing antibodies. Lineage B.1.1.7 (the Alpha variant) became dominant in early 2021, but the association between transmissibility and risk factors, such as age of primary case and viral load remains poorly understood. Here, we used comprehensive administrative data from Denmark, comprising the full population (January 11 to February 7, 2021), to estimate household transmissibility. This study included 5,241 households with primary cases; 808 were infected with lineage B.1.1.7 and 4,433 with other lineages. Here, we report an attack rate of 38% in households with a primary case infected with B.1.1.7 and 27% in households with other lineages. Primary cases infected with B.1.1.7 had an increased transmissibility of 1.5-1.7 times that of primary cases infected with other lineages. The increased transmissibility of B.1.1.7 was multiplicative across age and viral load.
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Affiliation(s)
- Frederik Plesner Lyngse
- Department of Economics & Center for Economic Behaviour and Inequality, University of Copenhagen, Copenhagen, Denmark.
- Danish Ministry of Health, Copenhagen, Denmark.
- Statens Serum Institut, Copenhagen, Denmark.
| | - Kåre Mølbak
- Statens Serum Institut, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Laust Hvas Mortensen
- Statistics Denmark, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Mads Albertsen
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | | | | | | | | | | | | | | | - Carsten Thure Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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