以色列人群新冠重复感染率大型队列研究 受访者供图
在国际上其它地区,重复感染已司空见惯。曹云龙提供的数据表明,最新流行株如BQ.1.1和XBB的重复感染率已达到40%,并在持续攀升。他表示,今年绝大部分国家都经历了四波重大感染高峰,多为不同突变株所诱导,平均三个月一次。目前看来,国内也很难完全避免。
重点关注奥密克戎在高危人群中的致病性
曹云龙表示,现在看到的奥密克戎的致病性整体上下降,主要是因为疫苗接种的普及以及大量人群感染导致的免疫力增强。虽然疫苗和自然感染建立的免疫屏障不能有效防止感染,但可以减轻症状,所以看上去似乎是病毒的致病性下降了。但他强调,这并不能与病毒的天然毒性相提并论。
曹云龙提到,社会群体中还有很多无法接种疫苗或者接种后无法产生有效免疫应答的人群,例如免疫缺陷人群、高龄老人、以及肿瘤患者等,他们也是新冠感染后发生重症和死亡的高危人群,因此仍然需要监测奥密克戎在这些高危人群中的致病性。
他介绍,在美国、英国、日本等国家,奥密克戎已经造成极大的死亡和重症负担。例如,在英国,奥密克戎BA.1造成的总死亡人数与Delta相当,虽然从BA.1→BA.2→BA.5,死亡峰值呈现下降趋势,但累计的死亡总数并没有大幅度下降。而日本今冬疫情造成的重症人数和死亡人数已逼近历史记录且尚未出现下降趋势。
曹云龙表示,目前的疫苗对重症的预防效果都较好,提高老年人的疫苗接种率仍具有重要意义。对于不适合疫苗接种的人群,则需要探索其他应对策略。
日本过去两年每日新增新冠死亡人数变化 受访者供图
广谱中和抗体有望提高治疗和预防效率
曹云龙认为,如何让疫苗和抗体药物的研发周期跟上病毒进化的速度是后续需要解决的问题。
“一个抗体药物的临床开发往往需要半年到一年的时间,也就是它能够使得社会受益的前提是该抗体能够应对未来半年到一年后所流行病毒。”曹云龙表示,新冠病毒突变较快,且免疫逃逸特性强,如何挑选开发广谱抗体药物,使得药物研发跟得上病毒突变至关重要,也是目前研发能够高效预防感染的疫苗所面临的痛点。
曹云龙团队建立了新冠免疫逃逸突变位点预测模型。他表示,预测到未来新冠会发生的突变,可以提前挑选出不受这些突变影响的抗体药物进行临床研发。
目前,曹云龙团队已开发两个广谱中和抗体SA55和SA58。据介绍,这两个抗体是从接种新冠疫苗的非典康复者体内筛选的,其作用位点避开了人群免疫的优势免疫表位,使得其很难被逃逸。
“SA55在目前的人群免疫背景中几乎不存在类似抗体,也是目前唯一一个处于临床开发阶段并对目前所有已知的新冠流行毒株都有效的抗体。”曹云龙介绍,SA55和SA58正在开展临床试验,产品剂型包括注射剂和喷雾剂。其中,注射剂可用于治疗和长效预防中重症,尤其适用于老年人或免疫缺陷人群等不适合疫苗接种或免疫反应差的人群。
与注射相比,喷雾剂直接作用于上呼吸道,只需很低的剂量就可实现预防感染的作用。初步安慰剂随机对照试验数据显示,SA58喷雾剂用于暴露后预防对有症状感染的保护效率可高达80%以上。“SA55活性更高,预防效率预计更高,且所需剂量会更低、成本也会更低”。
曹云龙提到,SA55/SA58喷雾有望成为一款可供全民居家日常使用的新冠预防和治疗产品,目前正在准备进行更为严谨的双盲临床试验。
新冠鼻喷中和抗体使用示意图 受访者供图
“虽然不能保证SA55未来一定不会逃逸,但我和团队已经在开发其他候选抗体,如果SA55被新毒株逃逸,可以马上有新的抗体替补。”曹云龙表示,除了广谱抗体,他和团队后续还将研发广谱新冠疫苗,以解决现有疫苗面临的技术瓶颈。(完)
中新网评:美国众议长选举“连续剧”暴露美式民主痼疾******
中新网北京1月9日电(蒋鲤)在15轮投票表决后,美国众议院议长选举这场“连续剧”终于落下帷幕,众议院共和党领袖凯文·麦卡锡最终成功当选第55任美国众议院议长。这是美国国会过去164年来耗时最久的一次议长选举记录,将美国“对抗式民主”的弊端暴露无遗。
资料图:美国众议院共和党领袖麦卡锡。中新社记者 沙晗汀摄
由于两党对立加剧、党派内斗、利益分配不均等因素,众议长选举陷入一场拉锯战。在此次众议长竞选中,美国民主党议员继续抱团,多轮投票中,一票不投麦卡锡,共和党右翼“强硬派”领头的约20人小团体也拒绝投票麦卡锡。
麦卡锡的当选之路一波三折,除了本人的“政治投机派”角色在国会不受欢迎外,与共和党内部政治分歧关系密切。
一方面,共和党党内反对者认为,麦卡锡对民主党态度过于软弱,无力对抗民主党控制的参议院和拜登政府,另一方面,因为共和党的多数优势微弱,党内一些影响力较小的派系的政治力量则被放大,有利于他们巩固自己的选票。
此外,党内反对者也认为,自己的选票没有换取更多利益,希望以此作为筹码换取麦卡锡更大的让步,比如让他们获得众议院重要委员会中的职务。
作为仅次于美国总统、副总统的政坛三号人物,众议院议长通常由众议院多数党领袖担任,选举几乎没有悬念。然而,麦卡锡此次为当选,不得不做出多个关键让步,其中可能包括恢复一项罢黜议长动议机制,使得众议长的权力被削弱,难以掌控众议院。
美国有线电视新闻网CNN称,麦卡锡在这场不合时宜的政治勒索中作出让步,这种绥靖政策只会让极端主义势力更加强大。
这场引发全世界围观的尴尬选举暴露出美国政治存在严重的对立和分化。在权力博弈思维的裹挟下,党派利益凌驾于国家和人民利益之上,美国两党相互拆台,陷入“为反对而反对”的无脑对垒。而即便是一党内,也会因为利益分配问题产生不同的小派系,相互对抗,选票变成了谋利益的工具。
从国会山骚乱到打破记历史记录的15轮众议长选举,“对抗式民主”让美国政治陷入瓶颈,长期对抗势必会让政客们丧失客观公正的判断能力,其政治阶层是否有能力治理国家也会引发质疑。
两党之争和党派内斗进一步放大了美国政治体制弊病,美国所谓的“民主”形象,让全世界大跌眼镜。鼓吹以选民利益为先的美式选举,变成了政客们利益置换的游戏,进一步彰显出美国“民主政治”日渐失能,不断极化的党争已使美国政治制度陷入死循环。
House speaker election reveals deep-rooted problems in U.S. democracy
(ECNS) -- The Republican leader Kevin McCarthy was elected as the 55th speaker of the U.S. House of Representatives after 15 ballots. As the most grueling House speaker election in the past 164 years, the election has highlighted the defects of the country’s "confrontational democracy".
The election once reached a stalemate due to intense partisan strife, inner-party struggle among the Republicans, uneven distribution of interests, and more. Democratic Party members forged a close alliance, refusing to vote for McCarthy, while about 20 Republicans also declined to cast ballots for the GOP leader.
Except for his unpopular role as a "political speculator" in Congress, McCarthy’s hard-won election can be attributed to turmoil within the Republican Party.
On the one hand, opponents in the Republican Party believe that the GOP leader's attitude toward the Democrats is too weak to confront the Senate controlled by Democrats and the Biden administration.
On the other hand, the political power of some less influential factions in the Republican Party has been amplified due to the Party’s weak majority advantage in the House of Representatives, which is conducive to consolidating their ticket warehouses.
Meanwhile, these opponents believe that their votes failed to win them more benefits, hoping to use this as a bargaining chip for McCarthy's further concessions, such as getting them positions in important House Committees.
As the third political figure after the President and Vice President of the U.S., the speaker, by tradition, is the head of the majority party in the House of Representatives.
But McCarthy has made many concessions in order to bring the ultra conservatives along, involving what’s known as the “motion to vacate,” a mechanism by which members can force a vote to depose the speaker. The reported concessions will empower individual members at the expense of McCarthy’s sway as speaker.
CNN thought the concessions he made during this unseemly political shakedown would only make the extremist faction more powerful.
This embarrassing election, which has drawn global attention, exposed the serious opposition and polarization in American politics. Both Democrats and Republicans put their interests before that of the country and its people, attacking and opposing each other irrationally.
Besides, different factions arise within a single party and confront each other because of the distribution of interests. Votes have become a tool to win more benefits.
From Capitol riots to the House Speaker election with record-breaking ballots, "confrontational democracy" has become a bottleneck of American politics. Long-term confrontation will surely impede politicians to think objectively and fairly while their capacity of governing the country will also raise doubts among the public.
Both parties’ struggle and infighting among the Republicans have further amplified the defects of the American political system, with its "democratic" image shocking the world.
The U.S.-style election, which advocates putting voters' interests first, has become a game of interest exchange among politicians. In addition, it further demonstrates the malfunction of American "democratic politics" and the constantly polarized party struggle that has trapped the American political system into an infinite cycle.
(文图:赵筱尘 巫邓炎)