印度的卫生专家正在寻找过去几个月新冠病毒病例大幅下降的主要原因。
New infections had climbed for months across India last year, but then began falling in September. Now the country is reporting about 11,000 new cases a day. That is down from nearly 100,000 during the worst period of the crisis.
去年印度各地的新增感染病例已经连续几个月攀升，但随后在9月份开始下降。现在，该国每天报告大约1.1万例新增病例。这比危机最严重时期的近10万例有所下降。
Experts studying the virus have suggested many possible explanations for the sudden drop, which happened in nearly every part of India. Two possible explanations are that some areas of the country may have reached “herd immunity” or that Indians may have some preexisting protection from the coronavirus. The term herd immunity describes a situation in which enough people in a population are resistant to a disease so that it cannot spread.
研究这种病毒的专家对印度每个地方都有发生的新增病例突然下降提供了许多种可能的解释。两种可能的解释是，该国的某些地区可能已经达到了群体免疫，或是印度人可能早就对新冠病毒存在某种防护。群体免疫是指人口中有足够多的人对某种疾病具有抵抗力，因此这种疾病无法传播。
The Indian government has said it believes the decrease happened, at least partly, because of mask-wearing across the country. Wearing a mask in public is a rule in India and is strongly enforced in some cities. But experts have noted that virus cases also dropped in areas where mask-wearing was less common.
印度政府称其认为病例下降至少有部分原因是因为全国各地佩戴口罩所致。印度在公共场合戴口罩是一项规定，某些城市执行非常严格。但是专家指出，一些戴口罩不太常见的地区，新冠病毒病例也有所减少。
Finding out causes for the drop could help officials better control COVID-19, the disease caused by the coronavirus. India has reported nearly 11 million COVID-19 cases and over 155,000 deaths.
找出病例下降的原因有助于官员们更好地控制由新冠病毒引发的新冠肺炎。印度报告了近1100万例新冠肺炎病例，死亡超过15.5万例。
Dr. Shahid Jameel studies viruses at India’s Ashoka University. “If we don’t know the reason, you could unknowingly be doing things that could lead to a flare-up,” he told The Associated Press (AP).
沙希德·贾米尔博士在印度阿育王大学研究病毒。他对美联社表示：“如果我们不知道原因，那么可能会不知不觉地做出一些导致病毒爆发的事情。”
India, like other countries, misses many infections, and there have been questions about how it counts its virus deaths. But pressure on the country’s hospitals also dropped in recent months. This suggests that the virus’ spread is slowing.
与其它国家一样，印度也错过了许多感染病例，人们对如何统计该病毒导致的死亡案例存有疑问。但是最近几个月该国医院的压力也有所减轻。这表明该病毒的传播正在放缓。
Recorded cases reached 9 million in November. At that time, official information showed that nearly 90 percent of all critical care beds with ventilators in New Delhi were full. This week, just 16 percent of those beds were occupied.
印度录得病例在11月达到了900万例。当时官方数据显示，新德里所有配备呼吸机的重症监护床有将近90%都已住满。本周，这些床位只有16%被占用。
Experts believe the drop cannot be the result of COVID-19 vaccines because India only began giving the injections in January. They say the effects of the vaccination program will only be seen later.
专家认为，病例下降不是新冠疫苗导致的结果，因为印度1月份刚开始接种疫苗。他们表示，疫苗接种的效果只有以后才能看到。
Vineeta Bal studies how the body fights disease at India’s National Institute of Immunology. She told the AP she thinks the drop in virus cases could be related to large areas reaching herd immunity.
维涅塔·巴尔在印度国家免疫研究所研究人体如何抵抗疾病。她对美联社表示，她认为新冠病毒病例下降可能跟大范围地区达到群体免疫有关。
But other experts have warned that even if herd immunity in some places is partly responsible for the drop, the population as a whole remains vulnerable. This means people must continue to take measures to protect themselves.
但是也有专家警告称，即使某些地区的群体免疫是造成病例下降的部分原因，但人口整体仍然很脆弱。这意味着人们必须继续采取措施保护自己。
New research suggests that people who got sick with one form of the virus may be able to get infected again with a new version. For example, Bal pointed to a recent study in Manaus, Brazil. It estimated that over 75 percent of people there had antibodies for the virus in October -- before cases saw a sharp rise again in January. “I don’t think anyone has the final answer,” she said.
最新研究表明，感染一种病毒的人士可能会再次感染病毒新变种。例如，巴尔提到了巴西马瑙斯最近进行的一项研究。该研究估计在今年1月病例急剧上升之前，该地区75%人口在去年10月份携带该病毒的抗体。她说：“我认为没有人有最终答案。”
Experts say another possibility is that many Indians get exposed to a series of diseases throughout their lives. That could help build up immunity against new viruses. Among diseases common in India are cholera, typhoid and tuberculosis.
专家表示，另一种可能是，许多印度人一生都暴露于一系列疾病当中。这有助于增强抵抗新病毒的能力。印度的常见疾病包括霍乱、伤寒和肺结核。
“If the COVID virus can be controlled in the nose and throat, before it reaches the lungs, it doesn’t become as serious,” said Dr. Jameel of Ashoka University. “Innate immunity works at this level, by trying to reduce the viral infection and stop it from getting to the lungs,” he added.
阿育王大学的贾米尔博士表示：“如果可以在病毒到达肺部之前，在鼻腔和咽喉中加以控制，它就不会变得那么严重。”他还说：“先天免疫可以通过试图降低病毒感染并阻止其进入肺部来达到这种效果。”
Even with the major drop in infections, Indian health officials are worried about new virus versions, or variants, slowing efforts to fight the coronavirus. Scientists have identified several new variants in the country, including some blamed for causing new infections in people who already had an earlier virus version.
即使感染大幅下降，印度卫生官员仍然担心病毒变种会延缓抗击新冠病毒的进程。科学家们已经在该国发现了几种新变种，其中一些变种被认为在感染过较早版本病毒的人当中造成了新的感染。
I’m Bryan Lynn.
我是布莱恩·林恩。(51VOA.COM原创翻译，禁止转载，违者必究！)