Local experts say the emergence of a new Covid variant causing global concerns has made it more important than ever for people to get their booster jabs.
The new strain, which has been detected in southern Africa, may turn out to be more transmissible than the Delta variant and existing vaccines may be less effective against it.
This has led to fears that booster rates may start to slip, if people expect the variant to spread and that jabs will offer lower protection.
But Dr Louise Smith, Norfolk's director of public health, said this would be precisely the worst response, and that the variant's emergence underlined how vaccines remained the best weapon to fight Covid-19.
She added: "Vaccination remains the best line of defence against Covid-19, including for new variants. We encourage anybody who hasn't yet had their first or second dose to do so, and for those eligible for their booster dose to take this up as soon as possible."
Experts have stressed that even if vaccines are less effective against the variant, they will still offer some protection.
It comes as new figures reveal that more than two-thirds of people in Norfolk and Waveney who are eligible for boosters have taken the option up.
As of this week, some 280,000 people in the region have received their third dose of the vaccine, 67pc of those who qualify for it.
The booster is available to all those aged over 40 who had their second doses more than six months ago, along with clinically vulnerable people and those working in care settings.
It also means 32.7pc of the entire Norfolk and Waveney population are now triple-jabbed - above the national figure of 27.4pc.
The success of the booster rollout locally had also seen two Norfolk local authority areas appear in the top 10 for take up for those under-50.
In South Norfolk, 6.8pc of the under-50s are triple-jabbed, the third highest percentage nationally, while in Broadland 6.5pc are, the 10th highest amount.
In efforts to further accelerate this roll-out, the Norfolk and Waveney CCG has opened up several of its large-scale vaccination centres to walk-in appointments.
No confirmed cases of the new variant, B.1.1.529, have been detected in the UK, but its spread in southern Africa prompted the government to impose travel restrictions on countries in that region.
News of its emergence prompted steep falls on global stock markets, amid fears it may stall the economic recovery from the pandemic.
Heath secretary Sajid Javid, who addressed Commons about the matter on Friday, said the variant was a "huge international concern". He added that more nations may be added to the travel red list if necessary.
He said experience has shown "we must move quickly and at the earliest possible moment". He added that as well as the concerns the variant may be more transmissible and make vaccines less effective, it may also affect one of the UK's Covid treatments, Ronapreve.
Prof James Naismith, director of the Rosalind Franklin Institute at Oxford University, told the BBC: "It's bad news, but it's not doomsday." The variant would "almost certainly" make vaccines less effective, but they would still work to some extent, he added.
Paul Hunter, a viral expert at the University of East Anglia, said it has the potential to become a "big problem".
He said: "We will not know more until we have more data about the spread in South Africa. If by the end of the week there are around 200 or so cases in Africa [currently there are 59] we could have a big problem on our hands."
Prof Hunter added that he was unsure whether travel restrictions would prevent the variant spreading or simply delay the spread - but added if it does spiral the way vaccines have been rolled out would be partly to blame.
He said: "I believe the world would have been far better working through the most vulnerable people globally, rather than wealthier countries working through their populations.
"If vaccines had been rolled out in order of vulnerability on a global basis then this may not have happened."
Scientists say variants are more likely to arise in unvaccinated populations.
What do we know about the new variant?
Known for now as B.1.1.529, UK scientists first became aware of the new strain on November 23 after samples were uploaded on to a coronavirus variant tracking website from South Africa, Hong Kong and then Botswana.
A total of 59 samples have been uploaded on to the website so far.
On Friday, it was then confirmed that cases had been identified in Israel and Belgium.
Despite only being tracked for the past five days, the virus has been identified as having 30 different mutations already. That is twice as many as the Delta variant, which has been the most prominent variant in the UK over the past few months.
It has not yet been classified as a 'variant of concern', but ministers and scientists have said they are worried about it.
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