University Medicine Greifswald, Ferdinand-Sauerbruch-Strasse, 17475, Greifswald, Germany.
Adv Exp Med Biol. 2024;1457:247-264. doi: 10.1007/978-3-031-61939-7_14.
It has been assumed that the COVID-19 vaccination reduces the risk of transmission to others. Results during the delta predominance show that the viral load in the vaccinated population is not consistently lower compared to the unvaccinated, and during the omicron predominance, the viral load was even somewhat higher. Levels of infectious SARS-CoV-2 were partly lower in the vaccinated population. Viral loads were mostly lower in re-infections compared to breakthrough infections. Viral clearance including the detection of infectious virus has mostly been described to be faster in the vaccinated population suggesting a shorter duration as a possible source for transmission. The epidemiological relevance of this finding remains uncertain. Approximately half of the transmission studies found lower secondary attack rates from the fully vaccinated population, but the results are probably best explained by the vaccination status of the contact population. Public health data from the UK show that the number of COVID-19 cases is higher among the fully vaccinated and boosted population who might be possible sources, in contrast to lower case numbers within the first three months among the vaccinated obtained in phase 3 trials on symptomatic cases. Overall, there is no convincing evidence that the COVID-19 vaccination significantly reduces the risk to transmit SARS-CoV-2 to others.
人们一直认为，COVID-19 疫苗接种会降低传播给他人的风险。在德尔塔变异株占主导地位期间的研究结果表明，与未接种疫苗者相比，接种疫苗者的病毒载量并不总是更低，而在奥密克戎变异株占主导地位期间，病毒载量甚至略高。接种疫苗者的 SARS-CoV-2 传染性水平部分较低。与突破性感染相比，再感染的病毒载量通常较低。包括检测到有传染性病毒在内的病毒清除速度在接种疫苗者中大多更快，这表明接种疫苗者的传播持续时间可能较短。这一发现的流行病学相关性仍不确定。大约一半的传播研究发现，完全接种疫苗的人群的二次攻击率较低，但结果可能最好通过接触人群的疫苗接种状况来解释。来自英国的公共卫生数据表明，完全接种疫苗和加强接种疫苗的人群 COVID-19 病例数较高，而在接种疫苗者中，在症状性病例的 3 期试验的前三个月内，病例数较低。总体而言，没有令人信服的证据表明 COVID-19 疫苗接种显著降低了将 SARS-CoV-2 传播给他人的风险。
