The Leeds Teaching Hospitals NHS Trust

Oxford AstraZeneca Vaccine Safety Update

The Oxford AstraZeneca Vaccine: it’s safe, tested and it works

Like all vaccines, the Oxford AstraZeneca vaccine had to meet strict standards of safety and effectiveness before it was approved for use in the UK. It has gone through the same extensive clinical trials and safety checks that all licensed medicines have to complete.

These showed that the vaccine is safe and offers very high levels of protection against the effects of Covid-19.

Millions of people have now had the Oxford AstraZeneca vaccine and there is no evidence of serious side effects linked to the vaccine.

How it works

The vaccine uses tried and tested technology that has been used for other vaccines, such as the flu jab. It is made from a weakened version of a common cold virus, which has been altered to look like the coronavirus. Like all vaccines, it teaches the body to fight the virus by stimulating the immune system to make antibodies and cells to fight the infection. The virus used in the vaccine is deactivated so it cannot make you ill and the components leave your body in a few days.

There are no animal or foetal products in the Oxford AstraZeneca vaccine – or any of the Covid-19 vaccines approved for use in the UK - and it does not alter your DNA.

 Who is it suitable for?

The vaccine has been shown to be effective for adults of all ages. Recent studies of people over 80 who had the vaccine found that a single dose gives high levels of protection against severe disease and reduced hospital admissions by over 80%. A study is underway to assess the safety and effectiveness of the vaccine for children and young adults but currently it is only approved for use in people aged 18 and over.

 Does the vaccine have any side-effects?

Like all medicines and vaccines, the Oxford AstraZeneca vaccine can cause side effects in some people. Very common side effects include pain or tenderness in the arm where you had your injection, feeling tired, headaches, general aches and mild fever.

These tend to happen in the first couple of days after the vaccination and last a few days. You can rest and take the normal dose of paracetamol to help you feel better.

Evidence from the trials showed that these reactions were less common after the second dose. It is important to remember that the effects of Covid-19 are far worse than any of the side effects from the vaccines.

Get protected

Like the other approved vaccines, the Oxford AstraZeneca vaccine is safe and tested and will protect you against serious illness from Covid-19, which has sadly led to the death of millions of people around the world. People will continue to be at risk from the disease if they do not take up the offer of a vaccine so please have your vaccine when you are offered it and help protect yourself from Covid-19.

Why have some countries paused Oxford AstraZeneca vaccinations?

Some European countries have temporarily paused the use of the Oxford AstraZeneca vaccine as a precautionary measure, following reports of blood clots in a small number of people who had recently had the vaccine.

This is against medical advice from the European Medicines Agency (the European regulator for medicines and vaccines) and the World Health Organisation (WHO), who have both said the vaccine is safe and should continue to be given.

The UK regulator, the Medicines Health Regulatory Authority, has said that there is no evidence to suggest the blood clots were caused by the vaccine and that they are also confident the vaccine is safe.

The number of blood clots reported (30 in almost five million people) is actually less than the number that would be expected to happen naturally. Following the concerns, AstraZeneca has also conducted a review of data from over 17 million people, which has shown no evidence of an increased risk of blood clots.

Many other countries, including Canada and Australia, have confirmed they are also continuing to use the Oxford AstraZeneca vaccine.

What the experts say:

Dr Phil Bryan, MHRA Vaccines Safety Lead

“Vaccine safety is of paramount importance and we continually monitor the safety of vaccines to ensure that the benefits outweigh any potential risks. Blood clots can occur naturally and are not uncommon. Reports of blood clots received so far are not greater than the number that would have occurred naturally in the vaccinated population. We are closely reviewing reports but the evidence available does not suggest the vaccine is the cause.”

Margaret Harris, spokesperson for the World Health Organisation (WHO)

“The Oxford AstraZeneca vaccine is an excellent vaccine and no relationship has been established between the shot and the health problems reported. It’s very important to understand that we should continue to be using the vaccine” 

European Medicines Agency

"There is currently no indication that vaccination has caused these conditions, which are not listed as side effects with this vaccine. The vaccine's benefits continue to outweigh its risks and the vaccine can continue to be administered while investigation of cases of thromboembolic events is ongoing."