There was huge relief at news that a possible Covid-19 vaccine might be available to the most vulnerable by Christmas - but an Observer poll found that more than a third of readers would not take it if offered.

Vaccines are one of the greatest advances in medicine, and have saved countless millions of lives. Thanks to them, mass killers like smallpox and tuberculosis are largely memories in the West.

But perhaps the success of a few forgotten childhood injections has blinded us to the horrors of the diseases they protect us against. and left us vulnerable to the suggestion that vaccines themselves are harmful.

The discredited health scare against the measles, mumps and rubella jab did much to raise suspicion of vaccines among people who wrongly thought of these disease as harmless childhood illnesses. Nowadays, there is a whole movement of 'anti-vaxxers' online spreading arguments based on fear, misunderstanding and ignorance of the science involved.

People have also forgotten that part of the reason vaccines work is not just because they protect individuals, but the whole of society because of a phrase we have heard a lot this year - herd immunity.

This is when so many people are already immune to a disease that it cannot spread from person to person easily. The level of inoculation varies among diseases: for measles, 19 out of 20 people must be vaccinated. For polio it is four in five.

Coronavirus is a new illness. We do not know how long immunity from a vaccine or from catching it might last, whether subsequent infections are as serious, or whether we may need boosters or annual jabs like flu. We do not how many need to be inoculated for herd immunity to arise - one estimate is that if a vaccine is 75 per cent effective, roughly two thirds of the population need to take it.

Many pharmaceuticals companies are rushing to produce a vaccine so that life can return to normal. Yes, full testing and scientific rigour is needed. But the best thing for everyone is for as many people as possible to take the vaccine so there is a chance of herd immunity to take effect and protect those who cannot take it.

Not getting a vaccination because of internet hearsay or inflated fears is not only dangerous to you but to others.

A successful vaccine offers a chance of a return to normality. And we should not just take it for ourselves, we should do it so everyone - even those who genuinely cannot take it - can be safer.