A new scheme which would allow an NHS system to extract patient data from GP surgeries in England was due to start in July, but has been pushed back to September amid concerns around privacy.
NHS Digital figures show there were 513,876 patients on GP registers in Shropshire, Telford and Wrekin as of June 1.
They will now have until August 31 to opt out of sharing their personal information.
The programme, GP Data for Planning and Research, would put the medical histories of 61 million patients across England into a new database.
The launch was delayed to September 1 following complaints from privacy campaigners and doctors that people did not have enough time to understand what was happening.
The scheme will collect information on people’s treatments, referrals and appointments over the past 10 years, alongside other data from medical records held on GPs’ systems.
NHS Digital says under the system entire GP records will not be collected and the data is protected – or pseudonymised – before it leaves the GP surgery to ensure patients cannot be directly identified.
Bosses say the data can only be accessed by organisations which will legitimately use it for healthcare planning and research purposes and all requests will be scrutinised.
Dr Jess Harvey, from Much Wenlock and Cressage Medical Practice, says while it is important for clinical services to be able to share data between themselves, officials need to be clearer on who the data will be shared with.
"I believe data sharing is essential in terms of allowing clinical services to share records between primary and secondary care which does benefit patient care," she said.
"But the question regarding this data is how it gets used. The issue is one of trust. It needs to be used by appropriate people.
"What the government need to be clear about is who the data will be shared with."
Dr Harvey says the kind of data that will be shared is expected to include information such as sex, ethnicity and sexual orientation, as well as allergies and diagnosis.
However, no names, addresses and written notes will be handed over.
Dr Harvey said: "Without data sharing we wouldn't have been able to organise the Covid vaccinations in the way we have done and there are lots of other benefits.
"The data needs to be limited to people who need it.
"What would be difficult is if this issue affects patients' attitude towards the NHS."
She has urged patients to seek out information available online so they can make an informed decision for themselves.
More details can be found at nhs.uk/your-nhs-data-matters
Simon Bolton, chief executive of NHS Digital, said the responsibility to safeguard the data it holds is taken "incredibly seriously".
He added: “We intend to use the next two months to speak with patients, doctors, health charities and others to strengthen the plan even further.”
NHS bosses say making better use of data could benefit millions of people across the country.
In the past data has been used to help better understand and develop cures for serious illnesses, such as heart disease, diabetes and cancer.
The current system for collecting patient data is over 10 years old and NHS chiefs say it needs to be replaced, hence the planned introduction of the new system.
Mr Bolton said: "Data saves lives and has huge potential to rapidly improve care and outcomes, as the response to the Covid-19 pandemic has shown.
"The vaccine rollout could not have been delivered without effective use of data to ensure it reached the whole population.
"We are absolutely determined to take people with us on this mission. We take our responsibility to safeguard the data we hold incredibly seriously."
NHS Digital says that patients can opt out of sharing their data at any time, though it will not be applied retrospectively.
Anyone wishing to opt out of GPDPR entirely should therefore do so before September 1.
The data will be pseudonymised to ensure patients cannot be directly identified.
But campaigners say pseudonymous is different from anonymous, meaning peoples’ identities will be disguised but could later be re-identified.
Cori Crider, director of digital privacy group Foxglove, said: “The Government must make sure every single patient in England is meaningfully informed about what is happening to their data."
The Royal College of GPs also welcomed the delay to introducing the new system, but said safeguards must be in place to ensure data is not used inappropriately.
Professor Martin Marshall, chairman of the Royal College of GPs, said: “It is essential that this time is used to properly communicate with the public and with clinicians so that patients and GPs have trust in the programme."
The British Medical Association has also welcomed the delay, saying it was needed to allow for a proper in-depth public information campaign to give people a chance to make an informed decision about whether they want their data collected as part of the new programme.