THE Omicron sub-variant is almost as infectious as measles, a former WHO expert has warned.
BA.2 is now the dominant form of the variant, after its sibling took over the country just before Christmas.
It is thought to be just as mild, especially in the vaccinated, but spreads far quicker.
Professor Adrian Esterman, an epidemiologist, has warned cases are going to “skyrocket”.
He wrote: “Omicron BA.2 is about 1.4 times more infectious than BA.1. The basic reproduction number (R0) for BA.1 is about 8.2, making R0 for BA.2 about 12.
“This makes it pretty close to measles, the most contagious disease we know about.”
Spending just 15 minutes with someone who has the measles is enough to spread it.
Until vaccinations got the disease under control it was a global problem – killing millions in the 80s. But now thanks to jabs for youngsters, outbreaks are limited.
In the UK Covid cases have steadily risen over the past week, with one study – that sees Brits log symptoms and infections – showing a record-breaking day yesterday.
The latest estimate from the Office for National Statistics shows around one in 25 people are now infected with Covid.
The ONS says it’s not clear exactly what is behind the rise, but it is likely it is a combination of no restrictions, waning immunity and a more contagious sub-variant of Omicron becoming dominant.
Health Secretary Sajid Javid told Sky News: “We keep the situation very carefully under review.
“There’s no other variant of concern out there that is an issue at this point in time.
“We have seen some rises in infections over the last week but given the increase in social mixing this was to be expected.
“And whilst the rate has gone up modestly in the last few days, that’s to be expected as we are now open as a country and there’s more social mixing, but there’s nothing in the data at this point in time that gives us any cause for concern.”
It comes as immunity starts to wane in older Brits, and hospital admissions creep up.
Due to this, and as cases rise, Brits over 75 years old, care home residents and people over 12 who are immunosuppressed can get a booster in a few weeks.
NHS England is prepped to start dishing out “spring doses” to eligible people later this month, as long as they are six months on from their last shot.
The original plan was to start the next phase of the rollout from April, but anyone who is eligible before then can have another vaccine.
It has not been confirmed when exactly this might start, with some reports suggesting from March 21 – so if you think you are eligible, wait for your invite.
The emergence of the “Deltacron” variant – a hybrid of Omicron and Delta – has also left a number of countries monitoring it closely.
But at the moments numbers are low and it is not clear if it poses any greater danger.
Mr Javid said that a “handful” of cases had been identified in the UK, but were “not of particular concern”.