tetano
Editor, Senior Moderator
Nat Commun
. 2022 Sep 30;13(1):5760.
doi: 10.1038/s41467-022-33498-0.
Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark
Frederik Plesner Lyngse[SUP] 1 2 3 [/SUP], Carsten Thure Kirkeby[SUP] 4 [/SUP], Matthew Denwood[SUP] 4 [/SUP], Lasse Engbo Christiansen[SUP] 5 [/SUP], Kåre Mølbak[SUP] 6 4 [/SUP], Camilla Holten Møller[SUP] 6 [/SUP], Robert Leo Skov[SUP] 6 [/SUP], Tyra Grove Krause[SUP] 6 [/SUP], Morten Rasmussen[SUP] 6 [/SUP], Raphael Niklaus Sieber[SUP] 6 [/SUP], Thor Bech Johannesen[SUP] 6 [/SUP], Troels Lillebaek[SUP] 6 7 [/SUP], Jannik Fonager[SUP] 6 [/SUP], Anders Fomsgaard[SUP] 6 [/SUP], Frederik Trier Møller[SUP] 6 [/SUP], Marc Stegger[SUP] 6 [/SUP], Maria Overvad[SUP] 6 [/SUP], Katja Spiess[SUP] 6 [/SUP], Laust Hvas Mortensen[SUP] 8 9 [/SUP]
Affiliations
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.
. 2022 Sep 30;13(1):5760.
doi: 10.1038/s41467-022-33498-0.
Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark
Frederik Plesner Lyngse[SUP] 1 2 3 [/SUP], Carsten Thure Kirkeby[SUP] 4 [/SUP], Matthew Denwood[SUP] 4 [/SUP], Lasse Engbo Christiansen[SUP] 5 [/SUP], Kåre Mølbak[SUP] 6 4 [/SUP], Camilla Holten Møller[SUP] 6 [/SUP], Robert Leo Skov[SUP] 6 [/SUP], Tyra Grove Krause[SUP] 6 [/SUP], Morten Rasmussen[SUP] 6 [/SUP], Raphael Niklaus Sieber[SUP] 6 [/SUP], Thor Bech Johannesen[SUP] 6 [/SUP], Troels Lillebaek[SUP] 6 7 [/SUP], Jannik Fonager[SUP] 6 [/SUP], Anders Fomsgaard[SUP] 6 [/SUP], Frederik Trier Møller[SUP] 6 [/SUP], Marc Stegger[SUP] 6 [/SUP], Maria Overvad[SUP] 6 [/SUP], Katja Spiess[SUP] 6 [/SUP], Laust Hvas Mortensen[SUP] 8 9 [/SUP]
Affiliations
- PMID: 36180438
- PMCID: PMC9524324
- DOI: 10.1038/s41467-022-33498-0
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.