Coronavirus diary, Sunday 22 November

The success achieved in developing an anti coronavirus vaccine is a remarkable story.

Faced with a task that could have taken years, scientists and pharmaceutical companies have produced a result in a matter of months. 

It was a race against time. 

The pandemic has already killed 1.34 million with Britain's  54,626 among the worst in the world. 

So how has success been achieved so quickly?

It is through international effort involving every country with the expertise and facilities. 

Developing a new vaccine is a well established, rigidly controlled, painstaking process. 

There are two methods. The first is to identify an existing virus or bug and gradually weaken it so that it is downgraded and then use it against the virus. Effective but it takes a long time. 

The second, as with coronavirus, is by 'genetic engineering', by  producing in the laboratory antigen - a toxic substance - into the body, creating antibodies - molecules - that find and neutralise the virus.

Then come the three stages to see if it works. The first with perhaps a handful of people, the second expanded to a larger group of different ages and health conditions.

The final step involves very large numbers - in one case with the coronavirus search, 30,000 from several countries. 

There are strict national and international rules throughout the process before a new vaccine is given the all clear and production can begin. The results are then monitored for years.

Although the human guinea pigs are usually volunteers, in many cases they are paid; in fact there are firms specialising in finding teams. 

One London company that provides accommodation, food and entertainment facilities says that, depending on the time taken, it can reach £4,000. The money is for their time and inconvenience, for any risk, they say.

The Pasteur Institute in France says it is using experiments with the well studied measles virus in its quest for a coronavirus vaccine.

'It is a relatively quick method because we can create a measles vaccine and produce a million  copies every year', said the Institute's Professor Frederic Tangy.

Scientists are also looking at the possibility of a modified version of seasonal  flu, he said. 

With two vaccines proved by trials to be over 90% effective, covering various age groups, and the probability of others, including Oxford University's,  being announced soon, the future has suddenly brightened.

An astonishing story.