This Morning's doctor and Superdrug's doctor ambassador Dr Zoe said: "Receiving a positive antibody test result does not confer immunity, and it is important that people understand a positive test result does not mean you can be any more relaxed with the required hygiene and social distancing measures as set out by the Government".
Mr Hancock said certificates are being considered for people who test positive for coronavirus antibodies.
Mr Hancock said: 'I can announce today that we have signed contracts to supply, in the coming months, over 10 million tests from Roche and Abbott.
The antibody tests will be rolled out from next week in a "phased way", with health and care staff, patients and residents to be eligible first to see if they have had COVID-19 already.
The tests are not without their critics.
"This is an important milestone and it represents further progress in our national testing programme".
Public Health England (PHE) has evaluated the tests and approved them as being safe and reliable for widespread use.
Hancock said yesterday: "This new test could provide accurate results nearly on the spot".
Earlier, the prime minister's spokesman said the tests will be "free for people who need them, as you would expect".
At the briefing, Mr Hancock added that the government could not now say if people who test positive for these antibodies are necessarily immune from COVID-19.
A top NHS official has warned the public not to buy coronavirus antibody tests from high street stores over questions about their reliability.
The Health Secretary said they would be particularly appropriate for health and care workers, adding: "This will enable health and care workers to carry on with their shift or immediately isolate on the same day, and could eventually offer the same benefit to the whole country".
If the new trial obtains approval, millions of people will be able to access the tests from July.
It comes as the PM scrapped the fees to use the NHS for overseas health service staff and care workers.
Antibody testing has been regularly billed by Boris Johnson and ministers as "a game changer" in the response to the virus, but previous antibody tests have proved unreliable. Sites in Philadelphia are still prioritizing tests for people with coronavirus symptoms who are hospitalized, have chronic medical conditions, reside or work in congregate settings, are essential workers, or are close contacts of those in cluster cases.
"They are just going to tell people to self-isolate when I would have thought the obvious thing to do is test them".
"We're developing this critical science to know the impact of a positive antibody test and to develop the systems of certification to ensure people who have positive antibodies can be given assurances of what they can safely do".
He said "All-cause mortality has come down at the same time as the COVID deaths have come down, and it is now at roughly the rate it is at in an average winter".
One apparent holdup for the test and trace system has been delays to a bespoke NHS phone app, which is meant to track all the people with whom someone who tests positive has come into recent contact with, by communicating with others' phones.
If the technique is deemed to be both successful and effective, it will be rolled out nationally within six weeks.