A vaccination for some could be possible before Christmas but a full roll-out will take 18 months, the county’s director of public health has said.

Dr Louise Smith, Norfolk’s director of public health, was asked about the likelihood of a vaccine by the end of the year on BBC Radio Norfolk.

Hopes have been raised after pharmaceutical companies Pfizer and BioNTech announced they had developed a jab offering 90pc protection from contracting Covid-19 during a major trial.

Dr Smith said it was “quite possible very small numbers” of key workers would be vaccinated by January, but a population-wide jab would take around 18 months.

She said: “I think it is quite possible we will see very small numbers being vaccinated. It’s not going to be straightforward.

“There is still a lot of data we don’t have about this virus. So the announcement we have seen is based on less than 100 cases followed up for seven days each. There is a lot of data still to collect. If we do see a vaccination coming in before Christmas it is likely to be focussed very, very specifically on frontline, key worker staff.”

The government has acquired 40 million doses of Pfizer and BioNTech vaccine as well as another 10 million doses being manufactured by the end of the year if it is approved.

Dr Smith said: “I anticipate that as the vaccine programme develops, other vaccines come online as well. We’re going to be really busy in this area but it’s going to be 18 months or so before it’s population-wide.”

Also in the interview, Dr Smith responded to questions about the effectiveness of the second national lockdown.

She said: “I think it will reduce the numbers [of coronavirus cases]. The question is by how much? We do need to get to a point where we don’t need to have these lockdowns. Nobody wants them. They’re not desirable for individuals or the economy.

“And the answer to that is going to be a really effective test and trace system. One of the key messages that we are really wanting to emphasis is if you have symptoms get a test, if you’re waiting for a test stay in self-isolation and if you’re told you’ve been in contact with a case please go home straight away and go into isolation.”