As with any medicine, the NHS will only offer a COVID-19 vaccination when it has been approved by the Medicines and Healthcare Products Regulatory Agency (MHRA), the official UK regulator.

Vaccines go through three phases of clinical trials – For example, in the third phase the Pfizer vaccine was given to 21,000 volunteers, including older people, and there were no serious safety concerns.

Each vaccine went through all the normal stages of development and approval. It happened quickly for several reasons, including:

• there had been vaccine work on other corona viruses
• there was no waiting for funding
• development stages were run in parallel

This video explains how COVID-19 vaccines were developed quickly.

You can learn more in this video from the MHRA.