南非发现新型新冠病毒变种，存在大量突变

据英国《卫报》25日报道，南非卫生官员在周四（25日）的新闻发布会上宣布，南非科学家发现一个新型变异新冠病毒，该毒株对通过疫苗遏制新冠病毒传播构成了“潜在重大威胁”。

南非科学家周四提供的最新数据显示，这种变异可能更具传染性，因为它的突变概率很高，而且已在该国人口最多的省豪登省的年轻人中迅速传播。

南非卫生部长法赫拉 (Joe Phaahla) 接受采访时说，这个已被世卫组织命名为“奥密克戎”的新冠病毒变异毒株“促使南非新冠确诊病例激增”，而科学家正在确定多大比例的新增病例是由该毒株引起。

令人担忧的是，不少专家形容这一变种病毒“非常可怕”，可能是迄今为止所发现的最凶猛的、他们所见过最糟糕的变种病毒，突变程度超过预期。

目前已在南非、博茨瓦纳和中国香港检测到了这种新毒株，其中以南非病例居多。

People queue outside a COVID-19 vaccination center in Cape Town, South Africa, as the country opens vaccinations for everyone 18 years old and above, August 20, 2021. /Reuters

Global authorities have reacted with alarm to a coronavirus variant detected in South Africa,  initially identified as B.1.1.529 and now named Omicron, with the EU, Britain, and India among those announcing stricter border controls as scientists seek to determine if the mutation is vaccine-resistant.

Since the COVID-19 outbreak, SARS-CoV-2, the virus that causes COVID-19, has changed over time. Most changes have little or no impact on their properties.

However, some changes may affect how easily they spread, their severity, or the performance of vaccines against them.

This one has drawn scrutiny because it has more than 30 mutations of the spike protein that viruses use to get into human cells, UK health officials say.

That is about double the number of Delta, and makes this variant substantially different from the original coronavirus that current COVID vaccines were designed to counteract.

South African scientists say some of the mutations are associated with resistance to neutralizing antibodies and enhanced transmissibility, but others are not well understood, so its full significance is not yet clear.

UK Health Security Agency Chief Medical Advisor Dr. Susan Hopkins told BBC radio some mutations had not been seen before, so it was not known how they would interact with the other ones, making it the most complex variant seen so far.

So more tests will be needed to confirm if it's more transmissible, infectious, or can evade vaccines.

The work will take a few weeks, the World Health Organization's technical lead on COVID-19, Maria van Kerkhove, said on Thursday. In the meantime, vaccines remain a critical tool to contain the virus.

No unusual symptoms have been reported following infection with the B.1.1.529 variant and, as with other variants some individuals are asymptomatic, South Africa's NICD said.

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