There was promising news in the search for an effective vaccine against coronavirus this week when a team at Oxford University announced its first results. It is one of around two dozen vaccines being tested on people in clinical trials – and there are around 140 others in development around the world.

The BBC’s online health editor Michelle Roberts answers some of your questions about coronavirus vaccines.

Would a vaccine be 100% safe – I am worried that a vaccine may be rushed out and there may be unwanted side-effects?

From Tim Pryke, Woodlesford, Leeds

New vaccines undergo rigorous safety checks before they can be recommended for widespread use. Although research into a coronavirus vaccine is happening at a very rapid pace, these checks are still happening in clinical trials.

Any treatment can have some side-effects and vaccines are no different. The most common side-effects of vaccines are typically mild and can include swelling or redness to the skin where the jab was given.

Is there any proof that the flu vaccine in 2019 and 2020 have been checked for Covid-19?

From Antonia Saluto, Bedford, England

The seasonal flu vaccine will not protect against coronavirus. Flu (influenza) and coronavirus are completely different diseases caused by different viruses.

Having a flu jab is a good idea, particularly during the coronavirus pandemic, to help protect your health.

Flu can cause severe illness in some people, and those at high risk – which includes the over-65s and people with long-term health conditions – can get a free flu jab on the NHS.

Are people who have transplants able to have the vaccine?

From Anne Lindo, Reading, England

Scientists are testing lots of different potential coronavirus vaccines. It is not yet clear which ones may be most effective, if any. Different versions may be more suitable for some people than others.

Tests are happening in volunteers but it will take time to get results and to know who might benefit from vaccination.

If you have received a transplant and are taking immunosuppressant drugs to prevent rejection, some vaccines, such as “live” vaccines containing weakened bacteria or viruses, may not be appropriate for you.

Would this vaccine still be effective if the virus mutates?

From Alan Ng, Dingley, Canada

The coronavirus vaccines being developed at the moment are based on the viral strain currently circulating.

Viruses can mutate, but this will not necessarily make the corresponding vaccine less effective. It depends how significant the mutations are and whether they affect the part of the virus the vaccines are designed to safely mimic.

Many of the experimental coronavirus jabs currently being tested contain the genetic instructions for the surface spike protein that coronavirus uses to attach to and infect human cells. Reassuringly, scientists have not seen any substantial mutations to this part of the virus yet that would render these vaccines useless.

Source BBC