Those who have received the vaccine are being urged to look out for five symptoms which could lead to health problems.
The Birmingham Mail reports how the warning comes after it was confirmed under-40s are to be offered an alternative to the jab.
Worrying signs include bad headaches, blurred vision, stomach pain or skin rashes.
The Joint Committee on Vaccination and Immunisation (JCVI) said there is an “extremely small risk” of people suffering blood clots after having the jab, but the risk of illness with Covid-19 also drops for younger people as infection rates fall across the country.
Professor Wei Shen Lim, Covid-19 Chair for JCVI said that safety remains the number one priority.
But five worrying signs have been circulated by expects – and they are as follows:
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The Medicines and Healthcare products Regulatory Agency (MHRA) is currently appraising the jab and the review is said to be at an advanced stage.
Experts have also assessed the risks from any third wave of Covid in the UK and concluded that that wave is likely to be smaller than previously anticipated, therefore the risks to younger people are lower.