Abstract：
The COVID-19 pandemic led to unprecedented changes in behaviour. To estimate if these persisted, a final round of the CoMix social contact survey was conducted in four countries at a time when all societal restrictions had been lifted for several months. We conducted a survey on a nationally representative sample in the UK, Netherlands (NL), Belgium (BE), and Switzerland (CH). Participants were asked about their contacts and behaviours on the previous day. We calculated contact matrices and compared the contact levels to a pre-pandemic baseline to estimate R0. Data collection occurred from 17 November to 7 December 2022. 7477 participants were recruited. Some were asked to undertake the survey on behalf of their children. Only 14.4 % of all participants reported wearing a facemask on the previous day. Self-reported vaccination rates in adults were similar for each country at around 86 %. Trimmed mean recorded contacts were highest in NL with 9.9 (95 % confidence interval [CI] 9.0-10.8) contacts per person per day and lowest in CH at 6.0 (95 % CI 5.4-6.6). Contacts at work were lowest in the UK (1.4 contacts per person per day) and highest in NL at 2.8 contacts per person per day. Other contacts were also lower in the UK at 1.6 per person per day (95 % CI 1.4-1.9) and highest in NL at 3.4 recorded per person per day (95 % CI 43.0-4.0). The next-generation approach suggests that R0 for a close-contact disease would be roughly half pre-pandemic levels in the UK, 80 % in NL and intermediate in the other two countries. The pandemic appears to have resulted in lasting changes in contact patterns expected to have an impact on the epidemiology of many different pathogens. Further post-pandemic surveys are necessary to confirm this finding.
摘要：
COVID-19大流行导致行为发生了前所未有的变化。为了估计这些是否持续存在，CoMix社会接触调查的最后一轮是在四个国家进行的，当时所有社会限制都已经取消了几个月。我们对英国的全国代表性样本进行了调查，荷兰(NL),比利时(BE),瑞士（CH）。参与者被问及他们在前一天的接触和行为。我们计算了接触矩阵，并将接触水平与大流行前基线进行了比较，以估计R0。数据收集时间为2022年11月17日至12月7日。招募了7477名参与者。有些人被要求代表他们的孩子进行调查。只有14.4％的参与者报告在前一天戴着口罩。每个国家的成年人自我报告的疫苗接种率相似，约为86％。平均记录的接触者在NL中最高，每人每天9.9（95％置信区间[CI]9.0-10.8），在CH中最低，为6.0（95％CI5.4-6.6）。工作中的联系人在英国最低（每人每天1.4个联系人），在荷兰最高，每人每天2.8个联系人。英国的其他接触也较低，为每人每天1.6（95％CI1.4-1.9），NL最高，为每人每天3.4（95％CI43.0-4.0）。下一代方法表明，密切接触疾病的R0在英国大约是大流行前水平的一半，80%在NL和中间在其他两个国度。大流行似乎导致了接触模式的持久变化，预计将对许多不同病原体的流行病学产生影响。大流行后的进一步调查对于证实这一发现是必要的。
