来源：中国日报双语新闻
随着新冠变异病毒德尔塔毒株肆虐全球，始于南京禄口国际机场的新一轮本土疫情已经蔓延至多个省市，疫苗的保护率以及是否要打第三针加强针成为公众热烈探讨的话题。
近日，国家卫健委详细回应了疫苗保护率的持久性、是否需要加强针等问题。
The National Health Commission has responded to key public concerns about COVID-19 vaccines and disease control policies amid a resurgence of novel coronavirus fueled by the Delta variant in recent weeks.
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疫苗保护率的持久性如何？
已有数据显示，与常规疫苗一样，新冠疫苗接种后，随着时间的延长，接种者体内的抗体水平都会下降，全程免疫后6个月，18到59岁的人群和60岁以上的人群，各类疫苗目标剂量组中和抗体水平大概会有1.4到12.4倍不等的下降。
Available data shows that like other vaccines, antibody levels in vaccinated people will go down as time goes by. Six months after full immunization, neutralizing antibodies in people aged 18 and above inoculated with any vaccines drop by 1.4 to 12.4 times.
但是抗体水平下降，并不表示疫苗的保护力不存在，它降到什么样的水平保护力就会消失，目前还在收集数据进行研究。
But declining antibody levels is not equal to loss of vaccine-induced protection. Research is underway to figure out how much of the decline will make protective effects disappear.
部分单位开展的加强免疫的研究结果显示，全程免疫后6个月到12个月，打加强针的话，可以在很短的时间内使中和抗体显著提高。这说明，疫苗第一阶段的免疫已经产生了非常好的免疫记忆，这种免疫记忆维持时间至少可以达到一年。
Some studies show that a booster shot delivered six to 12 months after initial immunization can markedly increase neutralizing antibodies in a short span. This suggests that earlier vaccines have triggered very good immunological memory in human bodies, which can last at least a year.
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加强针的接种是否必要？
现在还没有足够的证据显示，需要对全人群都进行第三剂的疫苗接种。
There isn't enough evidence now to support delivering COVID-19 booster shots to individuals in the general public who have been vaccinated within a year.
对已完成免疫接种一年以内的普通人群，暂没有必要进行加强针接种。但是对完成免疫超过6-12个月，并且免疫功能较弱的老年人和有基础性疾病的患者，以及因工作需要要去高风险地区工作的人员，在国内从事高暴露风险职业的这些人群，是否有必要、什么时间开展加强针的接种，正在进行研究。
However, for the elderly with weak immune systems, those suffering from chronic illnesses, workers at higher risk of contracting the virus, or people planning to travel to high-risk areas, research is underway to determine whether a booster dose is needed six to 12 months after initial immunization, and if so, then when the booster shot should be rolled out.
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提供不同技术路线的疫苗
混合接种是否可行？
目前我国在新冠疫苗接种的过程中，不同技术路线疫苗不能替换。
During China's current mass immunization campaign, different types of vaccines cannot replace each other.
首针接种了灭活疫苗，后续就要用灭活疫苗来完成。如果是接种了CHO细胞的重组冠状病毒疫苗，后续的第二针、第三针也只能用CHO细胞的重组新冠病毒疫苗来完成。《新冠病毒疫苗接种技术指南（第一版）》中有此规定。
If a recipient is administered an inactivated vaccine, later inoculations must use inactivated vaccine. If the recipient is given a CHO recombinant protein subunit vaccine, then the second and third shot must also be the subunit vaccine.
即使同一个企业的同一个品种的疫苗不能完成接种，后续也要用相同技术路线的疫苗来完成后续的接种。
If a recipient cannot finish an inoculation with shots from one company, he or she must use the same type of vaccine to complete vaccination.
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60岁以上人群和12~17岁青少年
疫苗接种情况如何？
60岁以上老年人的接种工作，已经全部纳入到接种范围，截至7月28日，全国已经有1.5亿60岁以上老人接种了疫苗。
Seniors aged 60 and above have now been fully incorporated into the mass vaccination campaign. As of July 28, China had vaccinated 150 million people in this age group.
对于12-17岁未成年人的接种，采取的是分地区、分年龄段的方式，稳妥有序地推进，截至7月28日，已经累计接种了1248万人。
Vaccinations targeting youths aged 12 to 17 are also progressing smoothly, with 12.48 million in this age group vaccinated as of July 28.
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病毒变异，现在的防控措施
还有效吗？
目前我们的防控措施仍然有效。这个结论基于两个基本的认识：
一是科学界对这个病毒的认识。它仍然是个冠状病毒，它的传染源、传播途径已经基本清楚。
The first is that new virus strains are still of the coronavirus type, and its source of infections and transmission mode are clear.
二是基于我们国家目前防控工作的实践。因为我们现在的防控措施处置广东疫情、辽宁疫情、云南疫情等将近30多起疫情，效果是显著的。
Second, China's disease control measures have been effective in stemming nearly 30 local outbreaks in provinces like Guangdong, Liaoning and Yunnan. Their effects are obvious.
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暑假还能不能外出旅行？
疫情高中风险地区的人员要取消外出旅行。
People in medium- and high-risk areas should cancel their trips.
其他地区的人员出行前要认真查询旅行目的地的疫情风险状态，要暂缓前去高、中风险地区旅行。
People in other areas should check the risk status in planned destinations and postpone trips to areas at medium or high risk of the virus' spread.
无论到哪里旅行，都要做好个人预防，包括戴口罩、勤洗手，尽量避免和减少到室内人员拥挤的场所。在室外活动，也要注意保持适当的人际距离。
Wherever one goes, he or she should abide by personal preventive measures, such as mask wearing, washing hands regularly and avoiding indoor gatherings. In outdoor areas, keeping a distance is recommended.
老年人、慢性病患者，特别是那些尚未完成新冠疫苗全程接种或者全程接种新冠疫苗但还没有满14天的老年人和慢性病患者，尽量不去外地旅行。
The elderly and people with chronic diseases, especially those who have not been fully vaccinated for at least 14 days, should avoid traveling to other regions.
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为什么要继续坚持戴口罩？
即使打了新冠病毒疫苗也要继续戴口罩。
Even fully vaccinated people should keep their masks on.
对于个人来说，接种疫苗的保护效果不是100％，并且产生保护性抗体也需要一定的时间；对于群体来说，在没有形成免疫屏障的情况下，新冠病毒依然容易传播。所以，现阶段一些防控措施仍然要坚持，包括戴口罩、保持社交距离、勤洗手、通风等防护措施。
There is no guarantee that vaccines can provide protection for all individuals, and it will take time for vaccinated people to generate antibodies. In addition, the virus can still spread easily before herd immunity is established in a population.
在公共场所通风不好的密闭空间等建议戴口罩。
在空气流通不好地方，比如封闭的交通工具飞机、高铁、地铁、公交车等，封闭的公共场所如乘坐电梯这样通风条件不太好的地方，要戴口罩。到医院就诊或者陪同亲友看病，在医院环境中一定要戴口罩。此外，在公共服务窗口，像超市的收银、银行的柜台这些地方要戴口罩。
Mask wearing is recommended in public spaces with poor ventilation, including transportation vehicles and elevators, as well as at public service facilities such as cash registers at supermarkets or bank counters. At hospitals, people must wear masks.
来源：国家卫健委