It’s not often a piece of news is described as a “holy grail” but the latest study into one of the vaccines being administered in the UK could well deserve such an honour.

Why? Because it could mean a way out of lockdown sooner than we’d dared hope.

It’s worth stating that the research published by Oxford University has not yet been peer reviewed, but it is promising all the same.

So let’s look at what all the fuss is about…

The ‘holy grail’

The latest study of the Oxford/AstraZeneca vaccine appears to show it cuts transmission rates by 67%.

There are a lot of percentages around vaccines, so this is worth explaining fully.

We already knew the level of protection the jab offered – that is, how effective it is in stopping someone falling ill from the virus even if they come into contact with it.

Happily, the latest research shows this is actually higher than we thought – 76% up to three months after the first dose, rising to 82.4% after the second dose 12 weeks later.

What we we didn’t know was how effective it was in stopping people passing the virus on to others.

Why is this important?

If a vaccine only prevents a patient becoming severely ill, but they are still able to catch and pass on the virus, then everyone needs to have received a jab to be protected.

But if the vaccine also stops someone hosting and spreading the virus, then each vaccinated person also protects others.

Why didn’t we know this already?

Transmission isn’t something that can be measured in clinical trials as they can’t simulate the conditions of a vaccinated person going out and about amongst unvaccinated people for ethical reasons.

The only way scientists can measure this is to monitor the public rollout of the vaccine after its efficacy has been determined.

Senior public health officials have warned since the first vaccine was approved that there was no data to indicate what impact it would have on transmission rates.

Sounds positive, but what does it actually mean?

The fact it also seems to dramatically cut transmission after just one dose means lockdown measures can be lifted sooner, a former chair at the Faculty of Pharmaceutical Medicine said.

Dr Gillies O’Bryan-Tear said the results, which have yet to be peer reviewed, were the first definitive estimate of the impact of vaccination on transmission rates.

“If the effect on transmission is confirmed for the Pfizer vaccine too, this would be very positive,” he said.

“If these vaccines reduce transmission to the extent reported, it will mean that the easing of social restrictions will be enabled sooner, than if we have to wait for herd immunity – which may never in fact be achieved because of insufficient vaccine population coverage.”

He added: “That would be the holy grail of the global vaccine rollout, and these data bring us one step closer.”

What about mutant strains?

There are two points to consider here – how effective the current vaccine is against mutant strains and how much the vaccines reduce the likelihood of mutant strains occurring in the first place.

Viruses are live organisms and as such have the main principal drive that we humans do – to survive. Variations occur all the time and the ones that thrive are those that are more infectious and less deadly as they survive in the bodies of more and more people.

There are two major factors that increase the likelihood of a virus mutating. First is how much there is circulating in the population. The more virus about, the more chance some of it will mutate.

The news that the Oxford/AstraZeneca reduces transmission suggests it will reduce how much there is circulating in the public, thus reducing the chance of mutations which is very, very good news.

As for protection from the mutant strains that are already around, the news is similarly encouraging albeit slightly more caveated due to insufficient data at this time.

Professor Andrew Pollard, the chief investigator of the study into transmission, told the BBC’s Today programme: “We’re anticipating good protection against the Kent variant and we should have info to make public very soon.

“But when we look at the new variations [like the South Africa variant], that is the virus trying to escape from human immunity, whether that’s from a vaccine or previous infection.

“Hopefully it will be like other coronaviruses that are around us all the time that cause colds and mild infections… and we’ll have built up enough immunity to prevent the severe disease we’ve seen over the last year.”

When can I go to a pub or restaurant?

Steady on, the news is obviously positive but the rollout of vaccines is still going to take a number of months before enough people receive it for it to become effective at a population level.

Unfortunately, the only way to prevent mutations as mentioned above is to reduce transmission as much as possible which means sticking to restrictions for now.

Matt Hancock must be chuffed…

 He is very chuffed, describing the news as “absolutely superb”.

He also said it was vindication of the government’s decision to delay the rollout of the second jab which was initially going to be after three weeks rather than 12.

Hancock told Sky News: “That reduction in transmission, as well as the fact there is no hospitalisations, the combination of that is very good news and it categorically supports the strategy we’ve been taking on having a 12-week gap between the doses because it shows that the strength of the protection you get is, in fact, slightly enhanced by a 12-week gap between the doses. It is good news all round.”

Are there any caveats?

Yes. As with all preliminary scientific findings, the study has to be peer-reviewed just to check everything is in order.

Dr O’Bryan-Tear warned that, as yet, there is little data to show how the researchers calculated the 67% reduction in transmission in vaccinated participants compared to unvaccinated participants.

The paper is currently under review at the Lancet ahead of publication.

Dr O’Bryan-Tear said: “Few data were provided on how this figure was calculated, for example, how many samples it represented.

“We await fuller data and the publication, which will appear in the Lancet shortly.”