最快在周二，美国美国食品药品监督管理局可以授权新冠肺炎(新型冠状病毒肺炎)两名知情官员告诉美国广播公司新闻，为50岁以上的美国人注射加强剂，尽管第四针可能只是提供而不是正式推荐。
官员们强调，细节仍在讨论中，未来几天可能会有变化。
在本周早些时候FDA的预期授权后，疾病控制和预防中心将指导如何在全国各地的药店和医生办公室实施，因为这一过程已经在整个疫情进行。
官员们说，疾病预防控制中心主任罗谢尔·瓦伦斯基的话预计是50岁以上的人可以接受第二次加强注射，而不是应该接受第二次加强注射。
换句话说，人们可以根据自己的健康状况、风险承受能力和年龄做出个人决定。在过去，疾病预防控制中心曾使用类似的语言，首先向最脆弱人群，然后向普通人群开放加强注射。
FDA的专家小组将于4月6日召开会议，讨论更广泛的人群和接下来需要加强注射的人群，以及对特定变体加强剂的需求。
据另一位知情人士透露，权衡这一决定的官员还考虑到，今年春天获得强化的人可能会在今年晚些时候(可能是今年秋天)被推荐给更广泛的公众时再次获得强化。
辉瑞和Moderna上周要求FDA批准另一个加强剂量——特别是对老年美国人，这是一个免疫保护较弱的群体。
辉瑞要求FDA批准65岁以上的人服用第四剂，而Moderna要求批准18岁以上的人服用第四剂。
Officials expected to offer 2nd booster shot for those over 50 years old
As soon as Tuesday, the U.S. Food and Drug Administration could authorizeCOVID-19booster shots for Americans over 50 years old, two officials familiar with the matter told ABC News, though the fourth shots are likely to be only offered and not formally recommended.
The officials stressed that the details are still under discussion and could change in the next few days.
After FDA's expected authorization early this week, the Centers for Disease Control and Prevention will give guidance on how to implement it in pharmacies and doctors offices around the country, as the process has gone throughout the pandemic.
The language from CDC Director Rochelle Walensky is expected to be that people over 50 may get a second booster shot, rather than should get a second booster shot, officials said.
In other words, the shots would be available for people to make individual decisions based on their health, risk tolerance and age. In the past, the CDC has used similar language to open up booster shots first to the most vulnerable and then to the general population.
FDA's panel of experts will convene on April 6 to discuss the broader population and what population will need booster shots next, as well as the need for a variant-specific booster.
Officials weighing the decision are also considering that anyone who gets a booster this spring would likely get boosted again when they are recommended for the broader public later this year, potentially in the fall, according to another person familiar with the matter.
Pfizer and Moderna asked the FDA last week to authorize another booster dose -- especially for elderly Americans, a group that tends to have weaker immune protection.
Pfizer asked the FDA to authorize fourth doses for people older than 65, while Moderna asked for authorization for everyone 18 and older.
