Such infections are called "breakthroughs." They appear to be quite rare and usually cause little, if any, sickness.
这类感染被称为突破性感染。它们似乎非常罕见，通常很少会致病。

These breakthroughs are causing fear that the vaccines are not working.
这类突破性感染开始引发人们对疫苗不起作用的担忧。

But most experts disagree.
但是大多数专家并不认同。

Dr. Anthony Fauci is the top infectious disease official in the United States. He said infections among a very small number of vaccinated people do not mean the treatment is "failing." He said the vaccines are working well even against the Delta variant. It is now the leading cause of new infections worldwide.
安东尼·福奇博士是美国最高级别的传染病官员。他表示，极少数接种过疫苗的人士感染并不意味着疫苗失效。他表示，即使是针对德尔塔变种，疫苗也能很好地发挥作用。德尔塔变种目前是全球新增感染的主要原因。

The main reason most experts consider the vaccines successful is that very few breakthrough cases result in hospital treatment or death. Most do not cause any sign of sickness at all.
大多数专家认为疫苗成功的主要原因是，很少有突破性病例导致住院治疗或死亡。大多数根本不会引起任何生病迹象。

People who are vaccinated but still get sick generally have mild symptoms for a couple of days before the body starts fighting the virus.
接种疫苗但是仍然致病的人士通常会在身体开始对抗病毒之前的几天内出现轻微症状。

Only about 5,000 out of nearly 160 million vaccinated people have either died or been hospitalized in the U.S. and also tested positive for COVID-19.
在美国近1.6亿接种疫苗的人里面只有大约5000人死亡或住院，并且新冠肺炎检测呈阳性。

Medical experts are following the breakthrough cases. U.S. health agencies are considering whether vaccinated people should get an extra vaccine treatment called a "booster."
医学专家正在追踪突破性感染病例。美国卫生机构正在考虑接种过疫苗的人员是否应该额外补种一剂“加强针”。

People worry when they hear news like that which came from British Prime Minister Boris Johnson. He was very sick with COVID-19 last year and is fully vaccinated now. However, he went into quarantine this week after being around a person who tested positive.
人们在听到类似英国首相鲍里斯·约翰逊传出的消息时会感到担忧。去年约翰逊感染了新冠肺炎并且病得很重，并且目前他已经完全接种过疫苗。然而，本周他在接触一位检测呈阳性的人士后进入隔离状态。

But health officials in the U.S. want to be sure people are not overreacting to the breakthrough cases. That is because many people say they do not want to get the shots. The doctors worry those people will think getting the shot is not worth it if some people still get sick.
但是美国卫生官员希望确保人们不会对突破性病例反应过度。那是因为很多人表示他们不想接种疫苗。医生担心如果有人仍然感染，这些人会认为不值得接种疫苗。

Dr. William Schaffner is an infectious disease expert at Vanderbilt University. He said that is the wrong idea. People need to know the vaccines are doing their job.
威廉·沙夫纳博士是范德比尔特大学的传染病专家。他说那是错误的想法。人们得知道，疫苗正在发挥作用。

"The vaccines were developed to keep us out of those terrible institutions we call hospitals," he said. "We have to keep coming back to that."
他说：“疫苗的开发是为了让我们远离那些被称为医院的可怕机构。我们必须回到这一点上来。”