Omicron: Two Covid jabs provide weak protection against new variant, but boosters up to 75% effective

Omicron expected to be dominant variant in UK by next week, but health officials believe protection against severe disease and hospitalisation will remain high

Samuel Lovett
Science Correspondent
Friday 10 December 2021 19:53 GMT
Coronavirus in numbers
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Two Covid jabs don’t offer strong protection against symptomatic infection from the new omicron variant, government analysis shows – with the vaccines less effective than against delta.

However, those who have received a booster jab remain up to 70 per cent protected.

The government has warned that the country is facing a “deeply concerning situation”, with the UK set to experience an imminent surge in cases driven by the new variant, alongside a feared rise in hospital admissions among the unvaccinated or poorly protected.

The impact of the new variant is already being felt. Some 58,194 infections were reported in the UK on Friday – the highest total since 9 January. A further 448 cases of omicron were also confirmed, bringing the total to 1,265, but the real figure is now thought have surpassed 10,000.

Omicron is transmitting more effectively than delta and is expected to become dominant by next week, at which point it will account for more than 50 per cent of all infections, the UK Health Security Agency (UKHSA) said. Current trends suggest Britain will have reached more than one million omicron cases before the end of December.

How this translates into pressure on the NHS remains unclear, but Dr Susan Hopkins, chief medical advisor for the UKHSA, said there was concern that “even very small reductions in vaccine effectiveness against severe disease can cause an increase admissions”.

“The biggest worry is that we have if we have very high numbers of people getting infected at the same time, with the doubling rate that we’re seeing at the moment, then it will find out all those people who have less immune responses or those people who have yet to get their booster dose or have not been vaccinated yet.”

She said there are still more than five million people in England who have yet to receive a single dose of vaccine – a “significant” number.

UKHSA analysis shows that the AstraZeneca and Pfizer vaccines provide much lower levels of protection against symptomatic infection from omicron than delta, making the double-jabbed vulnerable to the variant.

However, individuals who had received a Pfizer jab following two doses of either vaccine were between 70 and 75 per cent protected, the research showed. Close to 40 per cent of all people aged over 12 in the UK have received a booster.

Vaccine effectiveness against severe disease from omicron is not yet known but is expected to be significantly higher than protection against mild infection, even after two doses. Data on this won’t be available for several weeks, the UKHSA said.

The analysis was based on 581 people infected with omicron, alongside thousands of delta cases. UKHSA warned against over-interpreting the results.

Dr Mary Ramsay, head of immunisation at the UKHSA, said the findings reaffirm the importance of getting a booster jab when eligible.

“These early estimates should be treated with caution but they indicate that a few months after the second jab, there is a greater risk of catching the omicron variant compared to delta strain. The data suggest this risk is significantly reduced following a booster vaccine.”

The government has said it intends to offer a booster jab to all over-18s by the end of next month.

No 10 has said that tougher Covid restrictions will be imposed if the worst fears about the omicron variant are realised. Contingency plans, dubbed a “Plan C”, have been drawn up by officials which are thought to include the return of table service in pubs and mask-wearing in more settings, in England.

Downing Street said it is not “aware” of any document listing the stricter measures being considered, just days after Boris Johnson triggered his Plan B – more comprehensive mask-wearing and guidance to work from home – to counter fast-rising omicron cases.

But the prime minister’s spokesman said: “We need to keep the characteristics of this variant under review and we would act if necessary.”

Communities secretary Michael Gove, who chaired an emergency Cobra meeting late on Friday, said the UK faces a "deeply concerning situation" given the fast spread of the omicron variant.

He said ministers had been presented with “very challenging new information” and revealed that 30 per cent of reported cases in London are now caused by omicron, which was only identified in the UK a fortnight ago.

Mr Gove also warned that evidence suggests omicron is "more likely" than past Covid-19 variants to "potentially" lead to hospital admissions among the fully vaccinated.

“Those facts mean that we do need to take action, and that's why we're bringing forward proposals to the House of Commons on Tuesday,” he said.

The warning comes as Nicola Sturgeon, first minister of Scotland, said the country could experience a “tsunami of infections” driven by omicron.

Echoing her England counterparts, Ms Sturgeon said the new variant could have a big impact on the NHS over the coming weeks. “A smaller percentage of a bigger number will still result in a massive number of cases who might need hospital care,” she said.

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