科学美国人(翻译)：儿童疫苗终于问世，新药研制面临的挑战 2022.6.28

Kids' Vaccines at Last and Challenges in Making New Drugs: COVID

儿童疫苗终于问世，新药研制面临的挑战

Tanya Lewis: Hi, and welcome to COVID, Quickly, a Scientific American podcast series.

Josh Fischman: This is your fast-track update on the COVID pandemic. We bring you up to speed on the science behind the most urgent questions about the virus and the disease. We demystify the research and help you understand what it really means.

坦尼娅·刘易斯：嗨，欢迎收看科维德，快播，美国科学播客系列节目。

乔希·菲奇曼：这是你对新冠病毒大流行的快速更新。我们将向您介绍有关病毒和疾病的最紧迫问题背后的科学知识。我们揭开了研究的神秘面纱，并帮助您理解它的真正含义。

Lewis: I’m Tanya Lewis.

Fischman: I’m Josh Fischman.

刘易斯：我是坦尼娅·刘易斯。

菲奇曼：我是乔希·菲奇曼。

Lewis: And we’re Scientific American’s senior health editors. Today we’re looking at COVID vaccines for the littlest kids–finally–and reasons for getting them… 

Fischman: ... and why vaccines, paradoxically, are making it harder to make new antiviral medicines.

刘易斯：我们是《科学美国人》的高级健康编辑。今天，我们来看看为最小的孩子接种的新冠病毒疫苗——最后——以及接种疫苗的原因

费斯曼：矛盾的是，为什么疫苗使制备新的抗病毒药物变得更加困难。

Fischman: At long last, kids under five years old are eligible for COVID vaccines. Can you bring us up to speed?

菲奇曼：五岁以下的孩子终于有资格接种新冠病毒疫苗了。你能告诉我们最新情况吗？

Lewis: Earlier this month the FDA authorized the Pfizer and Moderna vaccines for children six months through four or five years old, respectively. The decision came after an FDA advisory panel voted that the benefits of the shots outweighed the risks for these youngest children. The CDC’s own advisory panel also recommended the shots, and parents can now start to get their children vaccinated at doctor’s offices and other sites around the country.

刘易斯：本月早些时候，美国食品和药物管理局授权辉瑞和摩德纳分别为6个月至4岁或5岁的儿童接种疫苗。这一决定是在美国食品和药物管理局（FDA）的一个咨询小组投票认为，注射疫苗的益处大于这些最小儿童的风险之后作出的。CDC自己的顾问小组也推荐了这些疫苗，现在家长们可以开始在医生办公室和全国其他地方为孩子接种疫苗。

Fischman: The vaccines for adults got authorized more than a year ago. Why has it taken so long for little kids?

Fischman：一年多前，成人疫苗获得了批准。为什么小孩子要花这么长时间？

Lewis: Well Josh, you always have to be careful testing any new vaccine or drug in children. And the risk of severe COVID is greatest in older adults, so vaccine makers started by testing vaccines in that group first, then worked their way down to teenagers, then older kids, and finally, kids under five. 

刘易斯：乔希，在儿童身上测试任何新疫苗或药物时，你都必须小心。老年人患严重冠状病毒的风险最大，因此疫苗制造商首先在这一群体中测试疫苗，然后逐步深入到青少年，然后是年龄较大的儿童，最后是五岁以下的儿童。

Fischman: That makes sense. But kids can still get very sick with COVID, right? 

Lewis: That’s right. Even though the absolute risk of children getting severely ill from COVID is low, more than 440 children under five have died from the virus in the U.S., and many more have been hospitalized, especially during the recent Omicron waves. Children can also develop a condition called MIS-C, which causes inflammation in organs, including the heart, lungs, kidneys and brain. And they can get long COVID.

菲奇曼：这很有道理。但孩子们仍然可能患上严重的新冠肺炎，对吗？ 

刘易斯：没错。尽管儿童因新冠肺炎而患重病的绝对风险很低，但在美国已有440多名5岁以下儿童死于新冠肺炎，还有更多的儿童住院治疗，尤其是在最近的Omicron波期间。儿童也会患上一种叫做MIS-C的疾病，这种疾病会导致心脏、肺、肾和大脑等器官发炎。他们可能会感染长时间的新冠病毒。

Fischman: So young kids are not invulnerable. What do we know about the safety of the vaccines?

费斯曼：所以小孩子不是无懈可击的。我们对疫苗的安全性了解多少？

Lewis: Both Pfizer and Moderna used a smaller dose of their vaccines for little kids: Pfizer’s was three shots, each one-tenth of its adult dose and Moderna’s was two shots of one-quarter an adult dose. The side effects in the clinical trials were similar to those seen in older kids and adults: pain and redness at the injection site, headache, fatigue, irritability and fever. Fever is a concern with babies and small children because it can sometimes trigger seizures. Some of the kids in the trials developed fevers, and a handful had seizures, but the seizures were not thought to be related to the vaccine.

刘易斯：辉瑞和摩德纳都对小孩子使用了较小剂量的疫苗：辉瑞的疫苗是三针，每针是成人剂量的十分之一，摩德纳的疫苗是两针，成人剂量的四分之一。临床试验中的副作用与较大的儿童和成人相似：注射部位疼痛和发红、头痛、疲劳、易怒和发热。发烧是婴儿和幼儿的担忧，因为它有时会引发癫痫发作。试验中的一些儿童发烧，少数儿童癫痫发作，但癫痫发作被认为与疫苗无关。

There were also no cases of myocarditis or pericarditis—inflammation of the heart muscle or its lining. In rare cases, older children (mostly teenage boys or young men) developed this complication after vaccination, but it was generally mild and resolved on its own. There were no deaths of young kids in the trials.

也没有心肌炎或心包炎的病例心肌或其衬里发炎。在极少数情况下，年龄较大的儿童（主要是十几岁的男孩或年轻男子）在接种疫苗后出现这种并发症，但一般情况下病情轻微，并自行解决。试验中没有幼儿死亡。

Fischman: That’s definitely encouraging. What about the vaccines’ efficacy?

Lewis: That’s a harder thing to measure, but we know that both the Pfizer and Moderna vaccines met the FDA’s threshold for immune response. In other words, the levels of neutralizing antibodies produced in response to vaccination matched those of older kids or young adults.

菲奇曼：这确实令人鼓舞。疫苗的功效如何？

刘易斯：这很难衡量，但我们知道辉瑞和摩德纳疫苗都达到了FDA的免疫反应阈值。换句话说，接种疫苗后产生的中和抗体水平与年龄较大的儿童或年轻人的水平相匹配。

In terms of protection against COVID itself, the numbers of children who got COVID in the trials was so low that it’s hard to draw strong conclusions. But Pfizer’s three-dose vaccine appeared to have an efficacy of 76 percent in six- to 23-month-olds and 82 percent in two- to four-year-olds. Moderna’s two-dose vaccine had an efficacy of 51 percent in children aged six through 23 months and 37 percent among those aged two through five years. 

就预防新冠病毒本身而言，在试验中感染新冠病毒的儿童人数非常少，很难得出有力的结论。但辉瑞公司的三剂疫苗似乎对6至23个月大的儿童有76%的疗效，对2至4岁的儿童有82%的疗效。摩德纳的两剂疫苗对6至23个月的儿童的有效率为51%，对2至5岁的儿童的有效率为37%。

Fischman: Why was the efficacy so much lower than what we saw in adults and older kids?

Lewis: Well, the vaccine trials for different age groups took place when different variants of the SARS–CoV-2 virus were circulating. The trial of kids under five occurred during the first wave of Omicron, which is known to be better at evading our immune response. So it’s a bit like comparing apples and oranges.

菲奇曼：为什么疗效比我们在成年人和大孩子身上看到的要低得多？

刘易斯：不同年龄组的疫苗试验是在SARS-CoV-2病毒的不同变种传播时进行的。对五岁以下儿童的试验发生在奥米克罗的第一波浪潮中，众所周知，奥米克罗能更好地逃避我们的免疫反应。所以这有点像比较苹果和桔子。

That said, vaccine makers are currently testing newer formulations of the vaccines that target Omicron specifically, and those appear to be more effective at preventing symptomatic disease. In general, the current vaccines provide good protection against severe disease, especially with the booster shots.

这就是说，疫苗制造商目前正在测试针对奥米克罗的新型疫苗配方，这些配方在预防症状性疾病方面似乎更有效。总的来说，目前的疫苗可以很好地预防严重疾病，尤其是加强注射。

Fischman: So how are parents reacting, now that the vaccine is actually here?

Lewis: I spoke with a bunch of parents here in Brooklyn, New York, as well as in a few other cities, and the main feeling was relief. Some were frustrated. They said it had taken too long. Others were glad that the testing had been thorough.

菲奇曼：既然疫苗已经存在，那么父母的反应如何？

刘易斯：我在纽约布鲁克林和其他几个城市与一群家长进行了交谈，他们的主要感受是松了口气。一些人感到沮丧。他们说花了太长时间。其他人则对测试的彻底性感到高兴。

Still, many parents across the country are less thrilled about the prospect, surveys show. Only about one in five parents said they’re eager to get their child vaccinated right away, according to a Kaiser Family Foundation poll.

But two and a half years into the pandemic, the vaccine is finally available to pretty much everyone in the country who wants it.

调查显示，尽管如此，全国各地的许多家长对这一前景并不那么乐观。根据凯撒家庭基金会的一项民意调查，只有约五分之一的家长表示，他们渴望让孩子立即接种疫苗。

但在大流行两年半后，该疫苗终于可以提供给国内几乎所有想要它的人。

Lewis: Vaccines have saved countless lives. But their success is now making it harder to develop COVID treatments. That’s kind of odd, isn’t it?

刘易斯：疫苗挽救了无数人的生命。但他们的成功现在使得开发新冠病毒治疗变得更加困难。这有点奇怪，不是吗？

Fischman: It’s a bit hard to wrap your head around, Tanya, but yes: all the shots in arms, and some other factors, are slowing down trials of drugs that people can take if they get COVID. These are drugs like Paxlovid, to keep the disease from getting severe.

菲奇曼：坦尼娅，这有点难理解，但是是的：所有的手臂注射，以及其他一些因素，正在减缓人们在感染新冠病毒后可以服用的药物的试验。这些都是像Paxlovid这样的药物，用来防止疾病变得严重。

Basically, you want to test a drug on a group of people at risk for severe problems. But as more people get vaccinated, fewer people are at high risk, so it’s hard to find enough of them to test the drug.

基本上，你想在一群有严重问题风险的人身上测试一种药物。但随着越来越多的人接种疫苗，处于高风险的人越来越少，因此很难找到足够的人来测试药物。

Lewis: Wow. Is that really happening?

Fischman: It is. Here’s an example from Brazil. Nature News reported on a trial of drugs in that country to prevent serious disease and hospitalizations. It began in 2020, and 16 percent of people later had to be hospitalized, or died. It was easier to see if adding certain drugs could lower that number. But in 2021, vaccines had been rolled out. And the percentage of hospitalizations and deaths dropped to about 3-to-5 percent. 

刘易斯：哇。真的发生了吗？

菲奇曼：是的。这里有一个来自巴西的例子。《自然新闻》报道了该国为预防严重疾病和住院而进行的药物试验。从2020年开始，16%的人后来不得不住院或死亡。更容易看出添加某些药物是否可以降低这一数字。但在2021，疫苗已经推出。住院和死亡的比例下降到3%到5%左右。

That low number made it hard to find enough at-risk people and see if the drugs had beneficial effects. To get more people into the trial, the researchers had to expand it to several other countries, which slowed down testing a lot. 

这一低数字使得很难找到足够多的高危人群，也很难看到这些药物是否有有益的效果。为了让更多的人参与试验，研究人员不得不将其扩展到其他几个国家，这大大减缓了试验的速度。

Lewis: But we already have drugs that treat the disease, so what’s the urgency to find more?

Fischman: Well, we only have about a half dozen. And some of them, such as monoclonal antibodies, are fluids that have to be infused or injected into your body, so they’re hard to use in poorer countries without a lot of medical clinics. Plus many of these antibodies have lost effectiveness against new variants.

刘易斯：但我们已经有了治疗这种疾病的药物，那么迫切需要找到更多的药物吗？

菲奇曼：嗯，我们只有大约半打。其中一些，如单克隆抗体，是必须注入或注射到体内的液体，因此在没有很多医疗诊所的贫穷国家很难使用。此外，许多这些抗体已经失去了对抗新变种的效力。

Even the new pill, Paxlovid, has limits. It’s good in people who are elderly or who have other risk factors. But tests haven’t shown a strong benefit for younger people, and they get seriously ill too. So we need treatments for them.

即使是新的避孕药Paxlovid也有其局限性。这对老年人或有其他危险因素的人有好处。但测试并没有显示出对年轻人有很大好处，而且他们也会患重病。所以我们需要对他们进行治疗。

There are also people whose symptoms have rebounded after they finished a course of Paxlovid. The symptoms aren’t worse than the original bout of the disease, and people did get better. But an improved drug could eliminate the rebound. Some doctors think rebound occurs when Paxlovid doesn’t reach all the pockets of virus hiding in your body.

还有一些人在完成一个Paxlovid疗程后症状有所反弹。症状并不比最初的一次发作更严重，人们确实有所好转。但是一种改进的药物可以消除反弹。一些医生认为，当Paxlovid无法到达隐藏在你体内的所有病毒袋时，就会出现反弹。

Lewis: It sounds like we shouldn’t expect a rush of new drugs. 

Fischman: We probably shouldn’t. But we shouldn’t be too pessimistic, either. Researchers have been creative about combining trial groups from different countries to get enough people into a study. And the existing success of some drugs gives scientists paths to explore further with new ones. But it is, like everything else with this pandemic, going to take some time.

刘易斯：听起来我们不应该期待新药的涌现。 

菲奇曼：我们可能不应该。但我们也不应该太悲观。研究人员创造性地将来自不同国家的试验组结合起来，让足够多的人参与研究。一些药物的现有成功为科学家提供了进一步探索新药物的途径。但是，就像这场大流行的其他一切一样，这将需要一些时间。

Lewis: Now you’re up to speed. Thanks for joining us. Our show is edited by Jeff DelViscio and Tulika Bose. 

刘易斯：现在你掌握了速度。谢谢你加入我们。我们的节目由Jeff DelViscio和Tulika Bose编辑。

Fischman: Come back in two weeks for the next episode of COVID, Quickly! And check out SciAm.com for updated and in-depth COVID news.

菲奇曼：两周后再来看下一集《新冠肺炎》，快点！看看SciAm。com获取最新和深入的新冠病毒新闻。