Even an effective coronavirus vaccine will not return life to normal early next year, a group of leading scientists has warned.
A vaccine is often seen as the holy grail that will end the pandemic.
But a report, from researchers brought together by the Royal Society, said we needed to be "realistic" about what a vaccine could achieve and when.
They said restrictions may need to be "gradually relaxed" because it could take up to a year to roll the vaccine out.
More than 200 vaccines to protect against the virus are being developed by scientists around the world in a process that is taking place at unprecedented speed.
"A vaccine offers great hope for potentially ending the pandemic, but we do know that the history of vaccine development is littered with lots of failures," said Dr Fiona Culley, from the National Heart and Lung Institute at Imperial College London.
There is optimism, including from the UK government's scientific advisers, that some people may get a vaccine this year and mass vaccination may start early next year.
However, the Royal Society report warns it will be a long process.
"Even when the vaccine is available it doesn't mean within a month everybody is going to be vaccinated, we're talking about six months, nine months ... a year," said Professor Nilay Shah, head of chemical engineering at Imperial College London.
"There's not a question of life suddenly returning to normal in March."
The report said there were still be "enormous" challenges ahead.
Some of the experimental approaches being taken - such as RNA vaccines - have never been mass produced before.
There are questions around raw materials - both for the vaccine and glass vials - and refrigerator capacity, with some vaccines needing storage at minus 80C.
Prof Shah estimates vaccinating people would have to take place at a pace 10 times faster than the annual flu campaign, and would be a full-time job for up to 30,000 trained staff.
"I do worry, is enough thinking going into the whole system?" he says.
Early trial data has suggested that vaccines are triggering an immune response, but studies have not yet shown if this is enough to either offer complete protection or lessen the symptoms of Covid.
Professor Charles Bangham, chair of immunology of Imperial College London, said: "We simply don't know when an effective vaccine will be available, how effective it will be and of course, crucially, how quickly it can be distributed.
"Even if it is effective, it is unlikely that we will be able to get back completely to normal, so there's going to be a sliding scale, even after the introduction of a vaccine that we know to be effective.
"We will have to gradually relax some of the other interventions."
And many questions that will dictate the vaccination strategy remain unanswered, such as:
- will one shot be enough or will boosters be required?
- will the vaccine work well enough in older people with aged immune systems?
The researchers warn the issue of long-term immunity will still take some time to answer, and we still do not know if people need vaccinating every couple of years or if one shot will do.
Commenting on the study, Dr Andrew Preston from the University of Bath, said: "Clearly the vaccine has been portrayed as a silver bullet and ultimately it will be our salvation, but it may not be an immediate process."
He said there would need to be discussion of whether "vaccine passports" were needed to ensure people coming into the country were immunised.
And Dr Preston warned that vaccine hesitancy seemed to be a growing problem that had become embroiled in anti-mask, anti-lockdown ideologies.
"If cohorts of people refuse to have the vaccine, do we leave them to fend for themselves or have mandatory vaccination for children to go to schools, or for staff in care homes? There are lots of difficult questions."