“It is increasingly evident that Omicron is highly infectious and there is emerging laboratory and early clinical evidence to suggest that both vaccine-acquired and naturally acquired immunity against infection is reduced for this variant,” Susan Hopkins, the chief medical adviser to the [British] Health Security Agency, said in a statement.
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[Omicron] appears to be the most contagious form of the virus yet, a previous case of Covid-19 provides little immunity to it, and vaccines seem less effective against it. But it also seems to cause less severe illness than earlier variants.
“I think we are looking at a horrible winter,” said Peter English, a [British] retired consultant in communicable disease control [of the outlook in Great Britain].
...experts say that what is known so far is worrying. Jeffrey Barrett, the director of the Covid-19 genomics initiative at the Wellcome Sanger Institute in Britain, said the new data made one thing clear: “It will spread very fast, even in countries that have a very high vaccination rate like the U.K.”
...Omicron is doubling roughly every three days, in [Great Britain], a country where 70 percent of people are fully vaccinated and 32 percent have had a booster dose, is “really striking,” he added.
“We haven’t seen that kind of rate of growth since I think the March 2020 time when the original virus was spreading in a totally naïve population, when none of us really knew anything about it,” he said.
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Britain’s Health Security Agency released new data on Wednesday that it said “suggests that Omicron is displaying a significant growth advantage over Delta,” which had previously been the fastest-spreading variant and has become the dominant one worldwide.
“It’s not going to take long before it becomes obvious in other places, but it’s clearer earlier here,” Dr. Barrett said. “I think other countries should basically assume the same thing is happening.”
