英国一项新研究发现，完成两剂疫苗接种的人依然会感染并传播新冠病毒，即使没有症状，传染性也和未接种者一样强。这意味着，即使周围人都接种了疫苗，未接种者仍然有可能感染新冠病毒。图片来源：路透社研究了英国家庭新冠病例的专家警告称，接种了两针新冠疫苗的人依然会感染新冠病毒并将病毒传染给共同居住的人。Double jabbed people are catching Covid and passing it on to those they live with, warn experts who have studied UK household cases.而且，打过两针疫苗的人传染性和没打过疫苗的人一样强。Individuals who have had two vaccine doses can be just as infectious as those who have not been jabbed.即使他们没有症状或症状很轻，他们将病毒传染给未接种疫苗的共同居住人的风险可达38%。Even if they have no or few symptoms, the chance of them transmitting the virus to other unvaccinated housemates is about two in five, or 38%.如果他们的共同居住人也完成了疫苗接种，那么感染风险就会下降到25%。This drops to one in four, or 25%, if housemates are also fully vaccinated.这份研究报告发表在《柳叶刀传染病》期刊上，详述了让更多人接种疫苗的重要性。The Lancet Infectious Diseases work shows why getting even more people vaccinated is important.专家警告称，即使周边的人都打了疫苗，未接种疫苗者感染病毒的风险也不能因此而消除。Unvaccinated people cannot rely on those around them being jabbed to remove their risk of getting infected, they warn.疫苗可以有效地防止接种者在感染病毒后发展成重症及死亡，但是在阻止病毒传播上就没那么有效了，尤其是在传染性更强的德尔塔变种毒株出现之后。Vaccines do an excellent job of preventing serious Covid illness and deaths, but are less good at stopping infections, particularly since the emergence of the more infectious Delta variant.随着时间流逝，疫苗的保护作用会减弱，需要打加强针才能增强保护作用。And over time, the protection offered by vaccines wanes and needs boosting with further doses.专家称，由于新冠病毒传播大多发生在家庭内部，确保每位适合接种疫苗的家庭成员都接种并及时补种加强针才是明智的做法。Since households are where most Covid transmission occurs, making sure every member who is eligible for a vaccine has had one and is up to date with their doses makes sense, say experts.2020年9月至2021年9月期间开展的这项研究涵盖了在伦敦和博尔顿接受聚合酶链反应检测（核酸检测）的440户家庭，研究结果如下：According to the study, which ran from September 2020 to September 2021 and included 440 households in London and Bolton doing PCR Covid tests:一，相比未接种疫苗者，接种两剂疫苗的人感染德尔塔病毒的风险较低，但是风险仍然不小；People who are double jabbed have a lower, but still appreciable, risk of becoming infected with the Delta variant compared with unvaccinated people二，接种两剂疫苗者和未接种疫苗者的传染性似乎一样强；They also appear to be just as infectious三，接种疫苗者能更快痊愈，但是他们的病毒载量峰值（此时的传染性最高）和未接种者差不多；Vaccinated people clear the infection more quickly, but their peak viral load - when people are most infectious - is similar to that seen in unvaccinated people四，这或许可以解释为什么接种疫苗者依然容易把病毒传染给家人。This may explain why they can still readily pass on the virus in household settings.该研究的领头人之一、英国伦敦帝国理工学院的阿吉特·拉尔瓦尼教授说：“我们目前所观察到的接种疫苗者传播病毒的情况表明，让未接种者接种疫苗以防止自身被感染及发展成新冠肺炎重症是至关重要的，尤其是进入冬天后，更多人会长时间呆在室内近距离相处。”Prof Ajit Lalvani, of Imperial College London, UK, who co-led the study, said: "The ongoing transmission we are seeing between vaccinated people makes it essential for unvaccinated people to get vaccinated to protect themselves from acquiring infection and severe Covid-19, especially as more people will be spending time inside in close proximity during the winter months.“我们发现人们在打完第二针疫苗几个月后感染率又开始升高，因此适合打加强针的人应该及时补种。”"We found that susceptibility to infection increased already within a few months after the second vaccine dose - so those eligible for booster shots should get them promptly."该研究的合著者、同样来自伦敦帝国理工学院的阿妮卡·辛格纳亚伽姆博士说：“我们的研究结果为接种疫苗对新毒株的效果提供了一些重要见解，尤其是德尔塔毒株持续在全球各地，甚至在疫苗接种率高的国家，引发大量新冠病例的原因。”Co-author Dr Anika Singanayagam, also from Imperial, said: "Our findings provide important insights into the effect of vaccination in the face of new variants, and specifically, why the Delta variant is continuing to cause high Covid case numbers around the world, even in countries with high vaccination rates.