Like all medicines, vaccines can cause side effects. Most of these are mild to moderate and short-term. Not everyone gets side effects.
If you are concerned about side effects, phone your GP for advice.
The official name of AstraZeneca's COVID-19 vaccine is 'Vaxzevria'. But most people call it 'AstraZeneca'.
Common side effects
The common side effects after the AstraZeneca vaccine are more likely after the 1st dose of the vaccine.
People aged 65 and older are less likely to experience common side effects.
More than 1 in 10 people may experience:
- feeling tired
- tenderness, bruising, pain or itching in the arm where you had the vaccine injection
- muscle pain
- joint pain
- fever (temperature of 38 degrees Celsius or above)
More than one in 100 people may have:
- redness or swelling where you had the injection
- a low platelet count (that doesn’t cause any symptoms)
Rare side effects
More than 1 in 1,000 people may experience:
- reduced appetite
- swollen lymph glands
Very rare side effects
Very rare side effects of the AstraZeneca vaccine include:
- very unusual blood clots
- capillary leak syndrome
Very unusual blood clots
Very rarely 1 in 100,000 people may develop very unusual blood clots with low platelets. 1 in 5 of these people may die.
These blood clots are less likely to be reported after the 2nd dose of the vaccine. The risk of this very rare condition is higher in younger people.
Your GP, doctor or the person giving you your vaccine can advise you on the risks and benefits of getting this vaccine.
Even though these side effects are very rare, you should know the symptoms to look out for.
Symptoms of very rare blood clots
Get urgent medical help if you get any of these symptoms in the weeks after the AstraZeneca COVID-19 vaccine:
- pain in the chest or stomach
- swelling or coldness in a leg
- severe or worsening headache (particularly 3 or more days after the vaccine)
- blurred vision
- persistent bleeding, under the skin where there was no previous injury
- multiple small bruises, reddish or purplish spots, or blood blisters under the skin
Most people who got these very rare side effects got them within 14 days of getting the AstraZeneca vaccine.
No need to take aspirin
You do not need to take aspirin before or after vaccination. These are very rare blood clotting conditions with low platelets. Aspirin would not have a beneficial effect.
You should continue to take any prescribed medication unless told otherwise by your GP.
Capillary leak syndrome
A very small number of people in Europe have experienced capillary leak syndrome after getting the AstraZeneca vaccine.
Capillary leak syndrome is a rare but serious condition. It can sometimes be fatal.
Do not get the AztraZeneca vaccine if you have previously had capillary leak syndrome.
Immediate action required: Call 999/ 112 or go to your nearest emergency department (ED) if:
you have had an AstraZeneca vaccine in the past few days and you notice:
- rapid swelling of your arms or legs
- sudden weight gain
You may also feel faint due to low blood pressure.
These are symptoms of capillary leak syndrome.
Serious side effects
Serious side effects, like a severe allergic reaction, are extremely rare.
Serious side effects after the AstraZeneca vaccine are seen in approximately 1 in 100,000 people.
Your vaccinator is trained to treat any serious allergic reactions.
Fever after COVID-19 vaccines
It’s common to develop a fever (temperature of 38 degrees Celsius or above) after any vaccination. This usually happens within 2 days (48 hours) of getting the vaccine. It usually goes away within 2 days.
You are more likely to get a fever after the 1st dose of this vaccine.
If you feel uncomfortable, take paracetamol or ibuprofen. Follow the instructions on the box or leaflet. Do not take ibuprofen if you are pregnant.
If your fever starts more than 2 days after you are vaccinated, or lasts longer than 2 days, you should self-isolate (stay in your room). Phone your GP to arrange a COVID-19 test.
If you develop COVID-19 symptoms after your vaccine
COVID-19 vaccines cannot give you COVID-19.
It is possible to get COVID-19 before getting your vaccine and not realise you have the symptoms until after your vaccination.
If you have symptoms after the 1st dose of your COVID-19 vaccine, you still need to have the 2nd dose. While you may get some protection from the 1st dose, having the 2nd dose will give you the best protection against the virus.
Self-isolate and phone a GP to arrange a COVID-19 test if you have a fever which:
- starts more than 2 days after you get your vaccine
- lasts longer than 2 days after you get your vaccine
Updates on COVID-19 vaccine side effects
The COVID-19 vaccines have gone through the same clinical trials and safety checks as all other licensed vaccines. But these vaccines are new and long-term side effect information is limited.
As more people in Ireland and around the world get vaccinated, more information on side effects may become available.
We will update this page with any new information.
Reporting side effects of COVID-19 vaccines
As with all vaccines, you can report suspected side effects to the Health Products Regulatory Authority (HPRA).
There are 2 ways you can report a suspected adverse reaction to a COVID-19 vaccine:
- through the HPRA's online adverse reaction report form
- by emailing or posting this adverse reaction report form to the HPRA (DOCX, 3 pages, 115KB)
As much information as is known should be provided, and where possible, the vaccine batch number should be included. You'll find this on your vaccine record card.
You can also ask your doctor or a family member to report side effects for you.
The HPRA cannot provide clinical advice on individual cases. Talk to your doctor or pharmacist about any medical concerns you may have.
This content was fact checked by vaccine experts working in Ireland.
Last updated: 11 June 2021 at 5.30pm