Casdon
The Covid virus can’t be compared with the flu virus EllanVannin, because there are a large number of flu viruses circulating worldwide, so each year the content of the vaccine is adapted to match the strain that is the most prevalent elsewhere at the time of development in the world - typically the UK vaccine is based on the experience in Australia in their winter before ours. Usually the predictions are not too far off, but some years the vaccine that is developed doesn’t match the strain of flu that is prevalent in the UK.
At the moment, because Covid 19 is a new virus, and is being studied worldwide for mutations, we will know quickly when a mutation that doesn’t respond to the vaccination develops, the scientists are already predicting what that might be and working on the vaccines to counteract.
Thankyou for this explanationcasdon