England’s deputy chief medical officer has said he will not be giving any “further airtime” to false information around vaccines.

Professor Jonathan Van-Tam told a Downing Street coronavirus briefing that vaccine misinformation was “exactly that”, adding he still expected strong demand for a Covid-19 jab.

His comments on Monday came as GCHQ reportedly launched a cyber operation to disrupt disinformation around vaccines being spread by hostile states.

Meanwhile, one of the UK’s leading fact checking organisations, Full Fact, said it was preparing for anti-vaccination posts to be “ramped up” online following news of a major vaccine breakthrough.

Interim results from a jab developed by Pfizer and its partner BioNTech were found to be more than 90% effective, the pharmaceutical firm announced on Monday.

Answering a question about misinformation spread by anti-vaccine groups, Prof Van-Tam said: “Vaccine misinformation has been out there ever since the first vaccines were made and it is exactly that, misinformation, and I don’t propose to give it any further airtime.”

He added: “If you look at the staggering likelihood of hospitalisation or death with increasing age and in the elderly, I predict very strongly that there will be a very significant demand in the elderly, in particular, for this vaccine and ones that follow.”

Prime Minister Boris Johnson said the anti-vax argument “holds no water”.

False information about vaccines has increased during the coronavirus pandemic, with Russia identified as one of the main spreaders of such content.

According to The Times, the UK spy agency GCHQ is now using tools developed to stop material created by so-called Islamic State from spreading against anti-vaccine propaganda.

GCHQ declined to comment on any of its operational matters.

Russia has been linked to a number of malicious online activities associated with coronavirus, believed to be part of efforts to undermine the West while boosting Russian interests.

Last month, it was accused of leading a misinformation campaign which looked to undermine trust in a British coronavirus vaccine by spreading crude images, memes and video clips online in an attempt to discredit its development.

Meanwhile, Full Fact said it was preparing for further attempts by anti-vaxxers looking to sow public doubt following the latest coronavirus vaccine breakthrough.

Full Fact editor Tom Phillips said: “I don’t think we’ve seen anything about it just yet but I would imagine that it will not be too long before we start seeing things.

“I wouldn’t be surprised if we start to see false claims about it relatively soon.”

Vaccine misinformation has made up a “sizeable amount” of the content reviewed by the organisation, Mr Phillips said.

He added that, due to the magnitude of the pandemic, pre-existing conspiracy theories have now been attached to Covid-19.

“I suspect that we will see many of the same claims being ramped up – the claims that this was part of a plot to force a vaccination on the population,” he told the PA news agency.