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. Establishing the relative transmissibility of emerging variants of SARS-CoV-2 is key for pandemic management. Here, the authors use full-population administrative data from Denmark linked to PCR test results and estimate that the Alpha variant was ~60% higher than other strains circulating in early 2021.
【저자키워드】 SARS-CoV-2, viral infection, Epidemiology, 【초록키워드】 pandemic, Risk factors, Neutralizing antibodies, risk, outcomes, Viral, Transmissibility, Viral load, B.1.1.7, attack rate, management, Lineage, Households, Alpha, age, Alpha variant, Lineage B.1.1.7, PCR test, Denmark, lineages, association, strain, test results, circulating, variants of SARS-CoV-2, dominant, were infected, New, Establishing, 【제목키워드】 age, transmissibility of SARS-CoV-2, Increased,