Of 22 cases of omicron confirmed as of November 30, 12 of them were linked to people who discovered they were infected more than 14 days after receiving their last vaccine, according to health officials.
Two of those 12 cases were detected in people who received the first dose of their vaccine more than 28 days ago, according to the British Health Safety Agency (UKHSA).
Six were not vaccinated at all and no vaccination information was available in two cases.
None of the cases were hospitalized or died.
The UKHSA said “most cases have a very recent sample date and there is a lag between onset of infection and hospitalization and death.”
The data does not show how well the vaccine protects against omicron infection, as the majority of cases related to the delta variant have occurred in people who were fully vaccinated.
More than 80 percent of the UK’s population over 12 has now had two jabs.
The UKHSA has now started publishing the number of new omicron cases per week.
As of December 1, there were 32 new cases of omicron in the UK – 32 in total so far – and more than 82,000 from Delta, for a global total of at least 1.4 million.
All variants combined, there were 50,584 new cases recorded in the past 24 hours on Friday at 9 a.m. and 143 deaths within 28 days of a positive test.
The omicron variant has been detected in 30 countries so far, according to data compiled by the US government.
The UKHSA has released a new risk assessment of the variant. He sounded a “red” alert for his presumed ability to evade the vaccine and natural immunity due to the high number of mutations.
He also gave a “red” alert to mutations that appeared to be able to “reduce antibody binding”.
The agency also said that the variant “is transmitted quickly and successfully” and that it is “biologically plausible” that it is more transmissible than the delta variant.
The UKHSA added that PCR tests are able to distinguish omicron from other variants.
He said sewage monitoring found “very little evidence” of omicron before November 21 – but recent data is being analyzed.
The World Health Organization has said that the omicron variant can be detected when the S gene is not present.