UPDATE 4-Oxford COVID-19 vaccine prompts immune response among adults old and young, AstraZeneca says

* Oxford vaccine produces immune response

* Details of the findings shortly to be published - FT

* UK health minister: We're not there yet

* Roll out expected in 2021 - British health minister (Recasts lead and headline, adds British health minister)

By Guy Faulconbridge, Kate Kelland and Kate Holton

LONDON, Oct 26 (Reuters) - The COVID-19 vaccine being developed by the University of Oxford produces a similar immune response in both older and younger adults, and adverse responses were lower among the elderly, British drug maker AstraZeneca Plc said on Monday.

A vaccine that works is seen as a game-changer in the battle against the novel coronavirus, which has killed more than 1.15 million people, hammered the global economy and shuttered normal life across the world.

"It is encouraging to see immunogenicity responses were similar between older and younger adults and that reactogenicity was lower in older adults, where the COVID-19 disease severity is higher," an AstraZeneca spokesman told Reuters.

"The results further build the body of evidence for the safety and immunogenicity of AZD1222," the spokesman said, referring to the technical name of the vaccine.

The news that older people get an immune response from the vaccine is positive because the immune system weakens with age and older people are those most at risk of dying from the virus.

The Financial Times reported earlier that the vaccine, being developed by Oxford and AstraZeneca, triggers protective antibodies and T-cells in older age groups - among those most at risk from the virus.

The Oxford/AstraZeneca vaccine is expected to be one of the first from big pharma to secure regulatory approval, along with Pfizer and BioNTech's candidate.

If it works, a vaccine would allow the world to return to some measure of normality after the tumult of the pandemic.

Immunogenicity blood tests carried out on a subset of older participants echo data released in July which showed the vaccine generated "robust immune responses" in a group of healthy adults aged between 18 and 55, the Financial Times reported.

Details of the finding are expected to be published shortly in a clinical journal, the FT said. It did not name the publication.

OXFORD VACCINE

British Health Secretary Matt Hancock said a vaccine was not yet ready though he was preparing logistics for a possible roll out.

"I would expect the bulk of the roll out to be in the first half of next year," Hancock told the BBC.

Asked if some people could receive a vaccine this year he told the BBC: "I don't rule that out but that is not my central expectation."

"We want to be ready in case everything goes perfectly but it's not my central expectation that we'll be doing that this year, but the programme is progressing well, we're not there yet," Hancock said.

Called AZD1222 or ChAdOx1 nCoV-19, the vaccine was developed by Oxford University scientists and licensed to AstraZeneca in April, which took on the task of scaling trials and production.

The vaccine is likely to provide protection for about a year, CEO Pascal Soriot said in June.

The British drugmaker has signed several supply and manufacturing deals with companies and governments around the world as it gets closer to reporting early results of a late-stage clinical trial.

AstraZeneca resumed the U.S. trial of the experimental vaccine after approval by U.S. regulators, the company said on Friday.

Staff at a London hospital trust have been told to be ready to receive the first batches of the vaccine being developed by the University of Oxford and AstraZeneca Plc, The Sun newspaper reported on Monday.

The Sun said the hospital, which was not identified, was told to prepare for the vaccine from the "week commencing the 2 November". (Additional reporting by Bhargav Acharya and Kanishka Singh in Bengaluru; Writing by Guy Faulconbridge in London; Editing by Angus MacSwan)