很少有研究评估灭活COVID-19疫苗加强疫苗对感染(易感性)的有效性,感染他人(传染性),并将疾病从一个传播到另一个(传播)。因此,我们进行了一项回顾性队列研究,以评估灭活COVID-19疫苗加强疫苗接种对易感性的有效性,传染性,并在2022年2月1日至4月21日的OmicronBA.2爆发期间在深圳传播。根据密切接触者及其指标病例的灭活COVID-19疫苗接种情况,将符合条件的个体分为四个亚组:第2-2组,完全接种疫苗的密切接触者,由完全接种疫苗的指标病例接种(参照组);第2-3组,由完全接种疫苗的指标病例接种的加强疫苗的密切接触者;第3-2组,由加强疫苗的指标病例接种的加强疫苗的密切接触者接种。应用单变量和多变量逻辑回归分析来评估加强疫苗接种的有效性。第2-2、2-3、3-2和3-3组的样本量分别为846、1、115、1、210和2、417。我们发现,加强疫苗接种对传染性的有效性为44.9%(95%CI:19.7%,62.2%)对于≥18岁的成年人,62.2%(95%CI:32.0%,78.9%)为女性密切接触者,和60.8%(95%CI:38.5%,75.1%)为非家庭密切接触者。此外,加强疫苗接种对传播的有效性为29.0%(95%CI:3.2%,47.9%)对于≥18岁的成年人,38.9%(95%CI:3.3%,61.3%)女性密切接触者,和45.8%(95%CI:22.1%,62.3%)为非家庭密切接触者。然而,针对易感性的加强疫苗接种没有提供任何保护作用.总之,这项研究证实,灭活COVID-19疫苗的加强疫苗接种对OmicronBA.2传播和传染性提供了低水平的保护和中等水平的保护,分别。然而,加强疫苗接种不提供任何保护以防止OmicronBA.2易感性。
Little studies evaluated the effectiveness of booster vaccination of inactivated COVID-19 vaccines against being infected (susceptibility), infecting others (infectiousness), and spreading the disease from one to another (transmission). Therefore, we conducted a retrospective cohort study to evaluate the effectiveness of booster vaccination of inactivated COVID-19 vaccines against susceptibility, infectiousness, and transmission in Shenzhen during an Omicron BA.2 outbreak period from 1 February to 21 April 2022. The eligible individuals were classified as four sub-cohorts according to the inactivated COVID-19 vaccination status of both the close contacts and their index cases: group 2-2, fully vaccinated close contacts seeded by fully vaccinated index cases (reference group); group 2-3, booster-vaccinated close contacts seeded by fully vaccinated index cases; group 3-2, fully vaccinated close contacts seeded by booster-vaccinated index cases; and group 3-3, booster-vaccinated close contacts seeded by booster-vaccinated index cases. Univariate and multivariate logistic regression analyses were applied to estimate the effectiveness of booster vaccination. The sample sizes of groups 2-2, 2-3, 3-2, and 3-3 were 846, 1,115, 1,210, and 2,417, respectively. We found that booster vaccination had an effectiveness against infectiousness of 44.9% (95% CI: 19.7%, 62.2%) for the adults ≥ 18 years, 62.2% (95% CI: 32.0%, 78.9%) for the female close contacts, and 60.8% (95% CI: 38.5%, 75.1%) for the non-household close contacts. Moreover, booster vaccination had an effectiveness against transmission of 29.0% (95% CI: 3.2%, 47.9%) for the adults ≥ 18 years, 38.9% (95% CI: 3.3%, 61.3%) for the female close contacts, and 45.8% (95% CI: 22.1%, 62.3%) for the non-household close contacts. However, booster vaccination against susceptibility did not provide any protective effect. In summary, this study confirm that booster vaccination of the inactivated COVID-19 vaccines provides low level of protection and moderate level of protection against Omicron BA.2 transmission and infectiousness, respectively. However, booster vaccination does not provide any protection against Omicron BA.2 susceptibility.