《新型冠状病毒肺炎防控方案（第九版）》发布以来，疫情监测、风险人员的隔离管理、中高风险区划定标准等有所调整。防控方案修订的依据是什么？不同风险区的划分有何变化？最新变异株是否对现有防控措施造成影响？针对社会关切，国务院联防联控机制权威专家在接受媒体采访时作出解读回应。
Health officials and experts responded to key concerns from the public about the ninth and latest COVID-19 disease prevention and control guideline released on June 28 during an interview on Saturday (June 16).
为何修订防控方案？
更加科学精准
< Why are revisions being made to the guideline? >
国家卫生健康委疾控局传染病防控处处长刘清表示，修订防控方案有三方面考虑：
Liu Qing, an official at the National Health Commission's bureau of disease prevention and control
一是疫情形势的变化。新冠肺炎疫情仍然在世界范围内持续流行，今年以来全国本土疫情发生频次明显增多，疫情波及地区范围较广，我国外防输入、内防反弹的压力不断加大，防控形势更加严峻复杂。
二是病毒变异的特点。作为优势流行株，奥密克戎的潜伏期缩短，传播能力和隐匿性更强，传播速度更快，给疫情防控带来新的挑战。
三是前期试点工作结果和疫情防控实践。国务院联防联控机制综合组今年4月至5月在大连、苏州、宁波、厦门、青岛、广州和成都等7个入境城市开展了为期4周的疫情防控措施优化试点研究工作。同时充分吸收借鉴了各地防控工作实践和疫情处置经验。
“第九版防控方案是对防控措施的优化，绝不是放松防控。”刘清表示，关键是要把该管住的重点管住、该落实的落实到位、该取消的坚决取消，进一步提高疫情防控的科学性、精准性。
The adjustments are based on the latest pandemic situation, new characteristics of dominant strains and experiences in pilot zones.
The mainland has been hit frequently with domestic flare-ups this year due to the virus' continued rampage overseas, and the high transmissibility and stealthiness of the Omicron variant has added pressure to China's defense. As a result, the State Council's Joint Prevention and Control Mechanism rolled out new measures on a trial basis in seven cities receiving inbound travelers for four weeks in April and May, and drew experiences from local practices to formulate the new document.
The ninth version is an upgrade of existing disease control measures and by no means signifies a relaxation of virus containment. It is now essential to enforce implementation and eliminate unnecessary rules to improve the precision of anti-COVID efforts.
A medical worker takes a swab sample from a resident for nucleic acid test at a community in Liwan district of Guangzhou, South China's Guangdong province, April 9, 2022. [Photo/Xinhua]
为何调整风险人员隔离期限？
病毒潜伏期缩短
< Why have quarantine times been shortened? >
中国疾控中心传染病管理处研究员王丽萍：
Wang Liping, a researcher at the Chinese Center for Disease Control and Prevention
4月至5月开展的疫情防控措施优化试点研究发现，奥密克戎变异株平均潜伏期缩短，多为2天至4天；绝大部分都能在7天内检出。
“为进一步提高新冠肺炎疫情防控措施的科学性、精准性，基于研究结果和国内多地的防控实践，第九版防控方案对疫情相关风险人员的隔离管控时限和方式进行了优化。”中国疾控中心传染病管理处研究员王丽萍说。
将密切接触者、入境人员隔离管控时间从“14天集中隔离+7天居家健康监测”调整为“7天集中隔离+3天居家健康监测”，密接的密接管控措施从“7天集中隔离”调整为“7天居家隔离”……
“这样的调整，是根据奥密克戎变异株的流行特点对防控措施进一步优化，不会增加疫情传播的风险，是精准防控的体现。”王丽萍说。
Research has shown that the Omicron strain has a short incubation period of two to four days, and most infections can be detected within seven days.
The new guideline states that inbound travelers will undergo seven days of centralized isolation followed by three days of at-home health monitoring, rather than the previous rule of 14 days of centralized quarantine plus seven days of health monitoring at home.
The adjustment will not increase the risk of the virus' spread and reflects the principle of precise virus control.
何时启动全员核酸检测？
明确界定条件
< What is the deciding factor for when to introduce mass nucleic acid testing?>
中国疾控中心传染病管理处研究员王丽萍：
Wang Liping, a researcher at the Chinese Center for Disease Control and Prevention
不同场景下，区域核酸检测策略应有所不同——第九版防控方案对此进一步予以明确。方案针对省会城市和千万级人口以上城市、一般城市、农村地区，分别明确了发生疫情后和常态化防控下的区域核酸检测策略。
王丽萍介绍，疫情发生后，如经流调研判满足“感染来源明确”“传播链清晰”“未发生社区传播”等条件，无需对发生疫情的区域开展全员核酸检测，将重点对风险区域和有时空交集的人员开展核酸筛查。
如经流调研判，传播链不清、风险场所和风险人员多、风险人员流动性大，疫情存在扩散风险时，需启动区域全员核酸检测。方案中明确界定了不同区域核酸检测范围、检测策略和终止条件。
The guideline clarifies that when a local outbreak occurs, there is no need to roll out mass testing if epidemiological investigation shows that the source of infections and the chain of transmission are clear and no community spread of the virus has occurred. In such cases, local authorities should focus on testing residents in at-risk areas and contacts of confirmed cases.
However, mass screening is necessary when the transmission chain is unclear and the cluster is at risk of further spreading. The guideline also details rules and strategies for mass testing.
高中低风险区如何划分？
无疫情县实行常态化防控
中国疾控中心传染病管理处研究员常昭瑞：
Chang Zhaorui, a researcher at the China CDC
根据第九版防控方案，高中低风险区是在有疫情的县（市、区、旗）内划分。没有疫情发生的县（市、区、旗），全域实行常态化防控措施。
中国疾控中心传染病管理处研究员常昭瑞介绍，高风险区是指病例和无症状感染者的居住地，以及活动频繁且疫情传播风险较高的工作地、活动地等区域，原则上以居住的小区或者村为单位划定，可根据流行病学调查的结果进行研判、调整风险区域范围。高风险区采取“足不出户、上门服务”的封控措施。对跨区域外溢的高风险区人员，采取7天的集中隔离医学观察。
中风险区是指病例和无症状感染者停留和活动一定时间，且可能具有疫情传播风险的工作地和活动地等区域。中风险区采取“人不出区、错峰取物”的管控措施。对跨区域溢出的中风险区人员，采取7天居家隔离医学观察。
低风险区是指中高风险区所在的县（市、区、旗）的其他地区。低风险区采取“个人防护、避免聚集”的防范措施。跨区域外出的低风险区人员离开时应持48小时核酸检测阴性证明。对跨区域外出的低风险区人员，不需要采取隔离管控措施，但要求3天内完成两次核酸检测，并做好个人健康监测。
The status of high, medium and low risk only applies to county-level regions seeing new infections, and the remaining regions only need to implement regular disease control measures, according to the guideline.
最新变异株是否造成影响？
防控方案仍适用
中国疾控中心病毒学首席专家董小平：
Dong Xiaoping, chief virologist at the China CDC
近期，奥密克戎BA.5亚分支正在成为全球主要流行毒株，并在我国引发本土聚集性疫情。中国疾控中心病毒学首席专家董小平表示，与其他奥密克戎亚分支相比，BA.5的致病力总体没有明显变化，第九版防控方案仍然适用。
第九版防控方案将对病毒的监测提到更高的位置，体现分层分级的核酸筛查方案，加密风险职业人群核酸检测频次，并增加抗原检测作为疫情监测的补充手段。
“第九版防控方案中的这些措施对于BA.4和BA.5亚分支来说都是有效的。”董小平说。
Despite BA.5 becoming the dominant strain globally and triggering locally transmitted outbreaks recently, there are no marked differences between the pathogenicity of the strain and that of other Omicron subvariants.
The new guideline has further highlighted the significance of monitoring for the virus, such as increasing the frequency of testing for high-risk work and adopting antigen tests as an additional tool. These measures are still effective against BA.4 and BA.5 strains.
