Geismar Cyril, Fragaszy Ellen, Nguyen Vincent, Fong Wing Lam Erica, Shrotri Madhumita, Beale Sarah, Rodger Alison, Lampos Vasileios, Byrne Thomas, Kovar Jana, Navaratnam Annalan M D, Patel Parth, Aldridge Robert W, Hayward Andrew
Institute of Epidemiology and Health Care, University College London, London, UK.
Centre for Public Health Data Science, Institute of Health Informatics, University College London, London, UK.
Wellcome Open Res. 2021 Dec 21;6:224. doi: 10.12688/wellcomeopenres.16974.2. eCollection 2021.
Increased transmissibility of B.1.1.7 variant of concern (VOC) in the UK may explain its rapid emergence and global spread. We analysed data from putative household infector - infectee pairs in the Virus Watch Community cohort study to assess the serial interval of COVID-19 and whether this was affected by emergence of the B.1.1.7 variant. The Virus Watch study is an online, prospective, community cohort study following up entire households in England and Wales during the COVID-19 pandemic. Putative household infector-infectee pairs were identified where more than one person in the household had a positive swab matched to an illness episode. Data on whether or not individual infections were caused by the B.1.1.7 variant were not available. We therefore developed a classification system based on the percentage of cases estimated to be due to B.1.1.7 in national surveillance data for different English regions and study weeks. Out of 24,887 illnesses reported, 915 tested positive for SARS-CoV-2 and 186 likely 'infector-infectee' pairs in 186 households amongst 372 individuals were identified. The mean COVID-19 serial interval was 3.18 (95%CI: 2.55-3.81, sd=4.36) days. There was no significant difference (p=0.267) between the mean serial interval for VOC hotspots (mean = 3.64 days, (95%CI: 2.55 - 4.73)) days and non-VOC hotspots, (mean = 2.72 days, (95%CI: 1.48 - 3.96)). Our estimates of the average serial interval of COVID-19 are broadly similar to estimates from previous studies and we find no evidence that B.1.1.7 is associated with a change in serial intervals. Alternative explanations such as increased viral load, longer period of viral shedding or improved receptor binding may instead explain the increased transmissibility and rapid spread and should undergo further investigation.
在英国，值得关注的B.1.1.7变异株（VOC）的传播性增强可能解释了其迅速出现和全球传播的原因。我们分析了病毒监测社区队列研究中假定的家庭感染源 - 感染者对的数据，以评估新冠病毒病的传播间隔，以及这是否受到B.1.1.7变异株出现的影响。病毒监测研究是一项在线的前瞻性社区队列研究，在新冠疫情期间对英格兰和威尔士的所有家庭进行随访。在家庭中有一人以上的拭子检测呈阳性且与发病情况相符的情况下，确定假定的家庭感染源 - 感染者对。关于个体感染是否由B.1.1.7变异株引起的数据不可用。因此，我们根据不同英格兰地区和研究周的国家监测数据中估计由B.1.1.7引起的病例百分比，制定了一个分类系统。在报告的24,887例疾病中，915例新冠病毒检测呈阳性，在372名个体中的186个家庭中确定了1�6对可能的“感染源 - 感染者”对。新冠病毒病的平均传播间隔为3.18天（95%置信区间：2.55 - 3.81，标准差 = 4.36）。VOC热点地区的平均传播间隔（平均 = 3.64天，（95%置信区间：2.55 - 4.73））与非VOC热点地区（平均 = 2.72天，（95%置信区间：1.48 - 3.96））之间没有显著差异（p = 0.267）。我们对新冠病毒病平均传播间隔的估计与先前研究的估计大致相似，并且我们没有发现证据表明B.1.1.7与传播间隔的变化有关。诸如病毒载量增加、病毒脱落时间延长或受体结合改善等其他解释可能反而解释了传播性增加和快速传播的现象，应进一步进行调查。
