Side effects of COVID-19 vaccines

Find out about vaccination side effects and what to do if you experience them.

Common side effects

Like all medicines, you might experience some mild side effects in the days after getting your vaccination. This is common, and a sign that your body is learning to fight the virus.

Most side effects do not last long, and will not stop you from having a second dose or going about your daily life. Some side effects may temporarily affect your ability to drive or use machinery.

The most common reported reactions are:

  • pain or swelling at the injection site
  • feeling tired or fatigued
  • headache
  • muscle aches
  • chills
  • joint pain
  • fever
  • redness at the injection site
  • nausea.

Some side effects are more common after the second dose.

Side effects of the COVID-19 vaccine are similar in young people to those seen in adults. 

If you feel uncomfortable

You can:

  • place a cold, wet cloth or ice pack on the injection site for a short time
  • rest and drink plenty of fluids
  • take paracetamol or ibuprofen.

Serious side effects

There are some side effects that are more serious but rare, like a severe allergic reaction.

Serious allergic reactions or anaphylaxis from the vaccine are rare. This is why people are observed for around 15 minutes post vaccination. Vaccinators are well-trained in managing these if they occur.


Myocarditis and pericarditis

Myocarditis is inflammation of the heart muscle, while pericarditis is inflammation of the tissue forming a sac around the heart. These conditions are usually caused by viral infections (including COVID-19), but they are also very rare and serious side effects of the Pfizer vaccine.

Symptoms of myocarditis or pericarditis linked to the vaccine generally appear within a few days, and mostly within the first few weeks after having the vaccine.

If you get any of these new symptoms after your vaccination, you should seek medical help, especially if these symptoms do not go away:

  • tightness, heaviness, discomfort or pain in your chest or neck
  • difficulty breathing or catching your breath
  • feeling faint or dizzy or light-headed
  • fluttering, racing or pounding heart, or feeling like it is ‘skipping beats’

If you feel any of these symptoms in the days or weeks after the vaccine, you should see a doctor — there will be no charge for the consultation.

You can also call Healthline on 0800 358 5453 any time to get advice.

If you have an immediate concern about your safety, call 111, and make sure you tell them you have had a COVID-19 vaccination, or have or had COVID-19 so they can assess you properly.


Blood clots are a very rare side effect of the AstraZeneca vaccine. It has occurred in around 1 in 100,000 people who have received the AstraZeneca vaccine.

Symptoms can include:

  • shortness of breath
  • chest pain
  • leg swelling
  • pain in arms or legs
  • severe or persistent headache
  • blurred vision
  • confusion or seizures (fits)
  • abdominal pain.

Very rare cases of Capillary Leak Syndrome (CLS) have been reported. The symptoms of this condition include rapid swelling of the arms and legs, sudden weight gain and feeling faint.

Very rare cases of Guillain-Barré syndrome (GBS) have also been reported. GBS is a rare immune disorder that causes nerve inflammation. Symptoms may include pain, numbness and muscle weakness in the arms and legs which may progress to the chest and face.

Booster side effects

Side effects of booster doses are like those from primary vaccine doses. These include pain, redness or swelling at the injection site, headache, nausea and feeling tired or fatigued.

When to seek help

If you feel any of these serious side effect symptoms in the days or weeks after the vaccine, you should see a doctor or other health professional. You can also call Healthline on 0800 358 5453 anytime to get advice.

If you have an immediate concern about your safety, call 111. Tell them you have had a COVID-19 vaccination, or have or had COVID-19 so they can assess you properly.

For information about uncommon and rare side effects, visit the Ministry of Health website.

Uncommon and rare side effects | (external link)

Allergic reactions

If you have had a severe or immediate allergic reaction to any vaccine or injection in the past, tell your vaccinator when you arrive.

Serious allergic reactions do happen but are extremely rare.

If you have a reaction when getting the vaccine, a health worker will be there to look after you and make sure you are okay.

How to report side effects

Reporting COVID-19 vaccine side effects means the safety of the Pfizer vaccine within Aotearoa New Zealand can be closely monitored.

You can report your own side effects, or side effects experienced by someone else (including a child). You do not have to be certain the vaccine caused the side effects to make a report.

Side effects are reported to the Centre for Adverse Reactions Monitoring (CARM).

Medsafe closely monitors and releases safety reports showing this data.

Report your side effects (external link)

Learn more about CARM (external link)

You may be invited to submit side effects via text

If you get a Pfizer booster, or a child in your care has had a paediatric (child) Pfizer vaccine, you may be invited by text to let us know about any side effects experienced in the days after. This is called a Post Vaccine Symptom Check.

The text invite will come from the Ministry of Health, and you will be asked to reply ‘YES’, ‘NO’, or ‘STOP'. All replies are free of charge.

If you want to take part, you will be sent a link to an online form.

Last updated: at