美国最高卫生官员周三宣布，拜登政府准备在9月20日这一周开始为许多美国人接种加强疫苗，援引的数据显示，辉瑞和Moderna疫苗对新冠肺炎的效力会随着时间的推移而减弱。
美国医务总监·维韦克·穆尔西在白宫简报会上说:“在审查了最新数据后，我们现在的临床判断是，现在是为新冠肺炎支持者制定计划的时候了。”。
白宫表示，此举是保持领先于病毒的必要举措，并敦促任何尚未接种疫苗的人接种疫苗。最终计划仍取决于美国美国食品药品监督管理局的正式签署。
建议是，任何接种辉瑞或Moderna疫苗的人都应该在第二针接种后八个月注射加强针，医护人员、养老院居民和老年人应该排在第一位。
“你不会想发现自己在后面玩追赶吧。白宫首席医疗顾问安东尼·福奇博士说。
随着德尔塔变种的激增，助推发射的问题变得越来越紧迫。
周三的决定主要是基于数据显示疫苗仍然有效，是预防严重疾病或死亡的最佳保证，但根据疾控中心的数据，这一关键指标也可能在几个月内减弱。
疾控中心主任罗谢尔·瓦伦斯基在简报会上说:“尽管我们的疫苗目前在预防住院方面效果良好，但我们看到了随着时间的推移和针对德尔塔变体的疫苗有效性下降的令人担忧的证据。”。
她说，这些数据主要来自“其他国家日益恶化的结果”。
瓦伦斯基说:“鉴于这些证据，我们担心目前针对严重感染、住院和死亡的强有力保护措施在未来几个月可能会减少，尤其是在那些风险较高或在我们疫苗接种推广阶段较早接种疫苗的人群中。
疾控中心坚持认为，疫苗仍然可以降低患重病的风险。周三，该机构公布的数据显示，疫苗仍能防止住院。在一项涉及21家医院的分析中，疾控中心发现，从3月到7月，辉瑞和Moderna对住院治疗的有效性至少保持在84%。
但这只是为了让人们远离医院。当谈到更温和的突破时，数据表明疫苗的有效性已经在减弱，尤其是在面临德尔塔变种的情况下。
老年人尤其如此，疾控中心的一项单独分析发现，3月至7月，辉瑞和Moderna疫苗的效力在养老院居民中“显著”下降，因为delta变体成为美国的主要毒株。
研究发现，这两种疫苗在去年冬天和早春对防止养老院居民感染的有效性为75%。但截至8月1日，这一数字降至53%。
“从5月到7月，疫苗的整体有效性确实在下降。贝丝以色列女执事医疗中心病毒学和疫苗研究中心主任丹·巴鲁赫博士说:“好消息是，疫苗对住院患者的有效性仍然相当强劲，没有太多下降的证据。
在白宫的简报会上，福奇还表示，他希望加强疫苗接种将使接种疫苗的人不太可能传播德尔塔变种，因为接种疫苗的人有突破性病例能够传播病毒。
福奇说:“你真的可以从这样做中获得多重好处——你可以从疾病、疾病的严重程度以及最终的感染和传播中获得好处。
他说:“这种增长带来的提振确实相当惊人。
考虑到好处，这位卫生局局长说，最终美国人只有打了三针才会被视为“完全接种疫苗”。
白宫还表示，美国有足够的疫苗供应，可以为每个人提供助推器。
白宫COVID协调员杰夫·齐恩茨说:“我们将确保所有美国人在大约八个月的时候方便、容易地获得他们的免费疫苗，他们的加强针。”。
近1.99亿美国人至少接种了一剂疫苗，绝大多数接种了辉瑞或Moderna。但是增强剂将在滚动的基础上给药，只在人们注射第二剂后8个月时才推荐。
目前，即将推出的助推器将只针对接受辉瑞和Moderna疫苗的人。但官员们表示，他们预计也会授权给接种强生疫苗的人使用增强剂。第一批J&J疫苗直到3月份才接种，拜登政府表示，预计几周后会有更多关于该疫苗有效性的数据。
提供加强注射的计划取决于美国食品和药物管理局对第三剂的安全性和有效性的正式认可，尽管美国疾病控制和预防中心、美国食品和药物管理局和其他机构周三的联合声明表明，这是一个既定的结论。
疾控中心也必须签署具体的建议。疾控中心顾问计划于8月24日开会讨论此事。疾控中心顾问可能会讨论的一个问题是，选择不同品牌的疫苗作为增强剂是否明智。关于是否“混合搭配”疫苗的研究一直在进行。
一个问题是，美国在疫苗接种上的努力是否会不公平地从疫苗接种仍远远落后的国家获取资源。
世界卫生组织(World Health Organization)周三早些时候在日内瓦举行的新闻发布会上表示，将向已经拥有救生衣的人发放额外救生衣的决定等同于“当我们让其他人在没有救生衣的情况下淹死时”，世界卫生组织卫生紧急情况项目执行主任迈克·瑞安(Mike Ryan)博士说。
白宫COVID团队周三坚持认为美国可以同时做到这两点。
“我不接受我们必须在美国和世界之间做出选择的想法，”穆尔西说。
他说:“我们清楚地看到我们对这两者的责任，我们必须尽一切努力保护国内的人们，同时认识到在世界范围内遏制大流行并让人们接种疫苗将是防止未来变异病毒上升的关键。
Biden administration to begin rolling out booster shots the week of Sept. 20
The Biden administration is prepared to begin rolling out booster shots for many Americans the week of Sept. 20, the nation's top health officials announced Wednesday, citing data that show the effectiveness of Pfizer and Moderna vaccines against COVID-19 diminishes over time.
"Having reviewed the most current data, it is now our clinical judgment that the time to lay out a plan for COVID-19 boosters is now," U.S. Surgeon General Vivek Murthy said at a White House briefing.
The White House said the move was necessary to stay ahead of the virus and urged anyone who hasn’t gotten a shot to do so. A final plan was still contingent upon the official sign-off by the U.S. Food and Drug Administration.
The recommendation will be that anyone who received Pfizer or Moderna vaccines should get a booster shot eight months after their second shot, with health care workers, nursing home residents and seniors first in line.
"You don’t want to find yourself behind playing catch up. Better stay ahead of it than chasing after it," said Dr. Anthony Fauci, chief medical adviser to the White House.
The question of booster shots has grown increasingly urgent as the delta variant surges.
Wednesday's decision was largely based on data showing that vaccines are still working and are the best assurances against severe illness or death -- but that key metric could also wane in a few months, according to CDC data.
"Even though our vaccines are currently working well to prevent hospitalizations, we are seeing concerning evidence of waning vaccine effectiveness over time and against the delta variant," CDC Director Rochelle Walensky said at the briefing.
That data is mostly coming from "worsening outcomes in other countries," she said.
"Given this body of evidence, we are concerned that the current strong protection against severe infection, hospitalization and death could decrease in the months ahead, especially among those who are at higher risk or who were vaccinated earlier during the phase of our vaccination rollout," Walensky said.
The CDC has maintained that vaccines still blunt the threat of becoming seriously ill. On Wednesday, the agency released data showing the vaccines still protect against hospitalizations. In one analysis involving 21 hospitals, the CDC found Pfizer and Moderna remained at least 84% effective against hospitalizations from March to July.
But that's just when it comes to keeping people out of hospitals. When it comes to more mild breakthroughs, data suggest vaccine effectiveness is already waning, particularly in the face of the delta variant.
This is especially true for the elderly, with a separate CDC analysis finding that Pfizer and Moderna vaccine efficacy dropped "significantly" among nursing home residents from March to July, as the delta variant became the predominant strain in the United States.
The study found that the two vaccines were 75% effective last winter and early spring at keeping the nursing home residents from getting infected. But that number dropped to 53% effective as of Aug. 1.
"It does appear overall vaccine effectiveness is declining from May to July. The good news is that vaccine effectiveness against hospitalizations has remained quite robust without much evidence of decline," said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center.
At the White House briefing, Fauci also said he's hopeful that boosters will make vaccinated people less likely to spread the delta variant since vaccinated people with breakthrough cases are able to spread the virus.
"You could really get multiple benefits from doing this -- you can get benefits for disease, severity of disease, and then ultimately infection and transmission," Fauci said.
"The increase with a boost is really quite striking," he said.
Given the benefits, the surgeon general said that eventually Americans will only be deemed "fully vaccinated" if they have three shots.
The White House also said the U.S. has enough vaccine supply to provide boosters to everyone.
"We will make sure that it is convenient and easy for all Americans to get their free vaccine, their booster shot, at around their eight month mark," White House COVID coordinator Jeff Zients said.
Nearly 199 million Americans have gotten at least one dose of the vaccine, and the vast majority got Pfizer or Moderna. But boosters would be administered on a rolling basis, only recommended as people hit eight-months since their second dose.
For now, the upcoming boosters will be aimed at people who received the Pfizer and Moderna vaccines only. But officials say they anticipate authorizing boosters for people who got the Johnson & Johnson vaccine as well. The first J&J vaccines weren't administered until March, and the Biden administration says it expects more data on the effectiveness of that vaccine in a few weeks.
The plan to offer booster shots is contingent upon an official sign-off by the FDA on the safety and effectiveness of a third dose, although a joint statement on Wednesday from the CDC, FDA and others suggested that was a foregone conclusion.
The CDC also has to sign off with specific recommendations. CDC advisers planned to meet Aug. 24 to discuss the matter. One issue likely to be discussed by CDC advisers is whether it will be advisable to opt for a different brand of vaccine as a booster. Studies on whether to "mix and match" vaccines have been ongoing.
One question is whether the U.S. effort on boosters will unfairly take resources from countries that are still very far behind on vaccinations.
The World Health Organization earlier on Wednesday equated the decision to handing out extra life jackets to people who already have them "while we’re leaving other people to drown without a single life jacket," Dr. Mike Ryan, executive director of the World Health Organization’s health emergencies programme, said at a news briefing in Geneva.
The White House COVID team was insistent Wednesday that the U.S. can do both.
"I do not accept the idea that we have to choose between America and the world," Murthy said.
"We clearly see our responsibility to both and we've got to do everything we can to protect people here at home while recognizing that tamping down the pandemic across the world and getting people vaccinated is going to be key to preventing the rise of future variants," he said.
