Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Connecticut Department of Public Health, Hartford, Connecticut, USA.
Clin Infect Dis. 2022 Oct 3;75(Suppl 2):S243-S250. doi: 10.1093/cid/ciac422.
During August 2021-September 2021, a Connecticut college experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant outbreak despite high (99%) vaccination coverage, indoor masking policies, and twice-weekly testing. The Connecticut Department of Public Health investigated characteristics associated with infection and phylogenetic relationships among cases.
A case was a SARS-CoV-2 infection diagnosed by a viral test during August 2021-September 2021 in a student. College staff provided enrollment and case information. An anonymous online student survey collected demographics, SARS-CoV-2 case and vaccination history, and activities preceding the outbreak. Multivariate logistic regression identified characteristics associated with infection. Phylogenetic analyses compared 115 student viral genome sequences with contemporaneous community genomes.
Overall, 199 of 1788 students (11%) had laboratory-confirmed SARS-CoV-2 infection; most were fully vaccinated (194 of 199, 97%). Attack rates were highest among sophomores (72 of 414, 17%) and unvaccinated students (5 of 18, 28%). Attending in-person classes with an infectious student was not associated with infection (adjusted odds ratio [aOR], 1.0; 95% confidence interval [CI], .5-2.2). Compared with uninfected students, infected students were more likely to be sophomores (aOR, 3.3; 95% CI, 1.1-10.7), attend social gatherings before the outbreak (aOR, 2.8; 95% CI, 1.3-6.4), and complete a vaccine series ≥180 days prior (aOR, 5.5; 95% CI, 1.8-16.2). Phylogenetic analyses suggested a common viral source for most cases.
SARS-CoV-2 infection in this highly vaccinated college population was associated with unmasked off-campus social gatherings, not in-person classes. Students should stay up to date on vaccination to reduce infection.
尽管接种率高达 99%、室内戴口罩政策和每周两次检测，2021 年 8 月至 9 月期间，康涅狄格州一所学院仍经历了严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）Delta 变体爆发。康涅狄格州公共卫生部调查了与感染相关的特征以及病例之间的系统发育关系。
病例是指在 2021 年 8 月至 9 月期间，通过病毒检测在学生中诊断出的 SARS-CoV-2 感染。学院工作人员提供了入学和病例信息。匿名在线学生调查收集了人口统计学、SARS-CoV-2 病例和疫苗接种史以及爆发前的活动。多变量逻辑回归确定了与感染相关的特征。系统发育分析比较了 115 名学生的病毒基因组序列和同期社区基因组。
总体而言，1788 名学生中有 199 名（11%）实验室确诊 SARS-CoV-2 感染；大多数学生完全接种了疫苗（199 名中的 194 名，97%）。攻击率在大二学生中最高（414 名中的 72 名，17%）和未接种疫苗的学生中最高（18 名中的 5 名，28%）。与感染学生一起上面对面课程与感染无关（调整后的优势比 [aOR]，1.0；95%置信区间 [CI]，.5-2.2）。与未感染的学生相比，感染的学生更有可能是大二学生（aOR，3.3；95% CI，1.1-10.7），在爆发前参加社交聚会（aOR，2.8；95% CI，1.3-6.4），并且在接种疫苗系列后≥180 天（aOR，5.5；95% CI，1.8-16.2）。系统发育分析表明，大多数病例的病毒来源相同。
在这所高度接种疫苗的大学人群中，SARS-CoV-2 感染与未戴口罩的校外社交聚会有关，而不是面对面的课程。学生应及时接种疫苗以减少感染。
