Early research into vaccines' effect on Covid-19 transmission has been described as “really encouraging” by Nadhim Zahawi.
A study by Oxford University shows jabs could reduce rates, but the vaccines minister added the full data may not be available for weeks.
Mr Zahawi said two ongoing Public Health England (PHE) studies into the impact of vaccines on Covid-19 could be key to England's route out of lockdown.
Boris Johnson is “hopeful” restrictions can be cautiously eased in the coming weeks, saying vaccines are providing “grounds for confidence”.
The Prime Minister said he wants the end of current national lockdown to be “irreversible” ahead of the publication of his “road map” next Monday.
This week, he will analyse data on case numbers, hospital admissions, deaths and the impact of the vaccine roll-out as he prepares his plan.
Mr Zahawi said early signs from Oxford University has been promising but PHE research – the Vivaldi study on care home residents and staff, and the Siren research on healthcare workers – will give a clearer picture on the efficacy of vaccines.
He told Times Radio: “We’ve got to make sure that you bring down the infection rates, hence why we’re waiting to see the data on transmission.
"The Oxford team had some early data which is really encouraging on transmission, which has to be peer-reviewed."
But he stressed it is currently uncertain how much of the reduction in infections being seen is down to lockdown restrictions or the vaccine roll out, and suggested the full research may not be available for a number of weeks.
“We have a couple of very large-scale studies related to giving us better data on the vaccines,” Mr Zahawi told the BBC's Radio 4 Today programme.
“We should be able to see really good data in the next few weeks from those studies.”
Preliminary data, comparing elderly people who have received the vaccine with those who have not, is starting to show it is cutting hospital admissions and deaths, according to the Times.
The paper said ministers have already been given data showing that vaccines are cutting illness by about two-thirds, while a separate study suggests jabs are reducing transmission.
But Mr Zahawi told Times Radio: “We’re beginning to see more and more data but at the moment it’s far too early to begin to speculate on the quality of the data.”
He said vaccine supplies at the moment are “finite” but expressed confidence that the government will reach its next target of vaccinating another 17 million people, including all over-50s and those in at-risk groups, by the end of April.
“I see much greater volume in March and April – tens of millions of doses coming through – and I’m confident that we’ll hit our target,” he told BBC Breakfast.
The Prime Minister said on Monday that there are “grounds for confidence” that vaccines are helping to curb the spread of coronavirus, not just in protecting those who received the jab.
He told a Downing Street press conference: “We have some interesting straws in the wind, we have some grounds for confidence, but the vaccinations have only been running for a matter of weeks.”
