Health Desk- 09 Dec 2020: One in 1,000 people in the UK have already died after being infected with coronavirus during the pandemic. This is the known threat from the disease that any risks have to be balanced against.
In medicine there is an important difference between "safe" and "harmless" and between "risk" and something being "risky".
So, what do we mean when we talk about Covid vaccines being "safe" to use?
"If you mean absolutely no adverse effect, then no vaccine is 'safe' and no drug is 'safe'. Every effective medicine has unwanted effects" says Prof Stephen Evans, from the London School of Hygiene & Tropical Medicine.
The UK's medicines regulator, the MHRA, has decided the Pfizer/BioNTech vaccine has met that standard.
There are some drugs that have truly brutal consequences on the body, but are still approved because they are considered worth the risk.