COVID-19: Vaccine side effects and reactions

Find out the side effects, the reported adverse events and allergic reactions to the Pfizer vaccine.

Last updated: 14 December 2021

On this page:

Rare side effects:

This page is about the Pfizer vaccine. For information about AstraZeneca, see AstraZeneca vaccines.

Common side effects

Like all medicines, you might experience some mild side effects 1–2 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.

Uncommon side effects reported include:

  • enlarged lymph nodes
  • feeling unwell
  • insomnia

Report your side effects

Rare side effects

There are some side effects that are more serious but very rare, like a severe allergic reaction or an inflammation of the heart. If you develop difficulty breathing, a racing heart, chest pain or feel faint immediately or in the days after the vaccine, you should seek medical attention.


Myocarditis is an inflammation of the heart muscle and it can be mild or serious. It is usually caused by viruses but it is also a very rare side effect of the vaccine.

Symptoms of myocarditis linked to the vaccine generally appear within a few days, and mostly within the first week after having the vaccine. If you get any of these new symptoms, you should seek medical help, especially if these symptoms don’t 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. You can also call Healthline on 0800 358 5453 anytime to get advice.

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

Allergic reactions

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

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

Bell's palsy

Temporary one-sided facial drooping (Bell's palsy) has been reported as a rare side effect, affecting every 1 in 1,000 to 1 in 10,000 people in the clinical trials.

When you’re likely to experience a side effect

Most side effects show within a day or two after being vaccinated.

What you may feel What can help When this could start

Pain at the injection site, a headache and feeling tired and fatigued. These are the most commonly reported side effects.

Place a cold, wet cloth, or ice pack on the injection site for a short time.

Do not rub or massage the injection site.

Within 6 to 24 hours

Muscle aches, feeling generally unwell, chills, fever, joint pain and nausea may also occur.

Rest and drink plenty of fluids

Paracetamol or ibuprofen can be taken, follow the manufacturer’s instructions.

Seek advice from your health professional if your symptoms worsen.

Within 6 to 48 hours

New onset chest pain, racing heart, or shortness of breath Speak to your health professional promptly if you develop any of these symptoms. Within 14 days

If you’re concerned about how you’re feeling

If you’re unsure about your symptoms or if they get worse, call Healthline:

Phone 0800 358 5453

If you’re concerned about your safety, call 111. Tell them you’ve had a COVID-19 vaccination so they can assess you properly.

Reported side effects in New Zealand

Side effects following COVID-19 immunisation are reported to the Centre for Adverse Reactions Monitoring (CARM).

Report COVID-19 vaccine side effects to CARM

Any side effects reported are suspected by the reporter to be caused by the vaccine. It doesn’t always mean the vaccine did cause the side effect.

Medsafe closely monitors and releases safety reports showing this data.

Timeframe: 20 February to 20 November 2021
COVID-19 vaccine administered: Pfizer/BioNTech (Comirnaty)
Total doses given: 7,349,778

  • Total reports received: 38,556
  • Total reports that were serious: 1,462
  • Total reports that were not serious: 37,094

The most common reported side effects

The top 10 reported adverse events were:

  • Dizziness: 12,041 reports
  • Headache: 11,617 reports
  • Lethargy: 9,469 reports
  • Pain at the injection site: 9,238 reports
  • Nausea: 8,258 reports
  • Chest discomfort: 6,105 reports
  • Influenza-like illness: 5,062 reports
  • Fever: 5,062 reports
  • Numbness: 3,690 reports
  • Shortness of breath: 3,609 reports

Serious adverse cases reported

Medsafe's reports give detailed information about serious adverse cases reported. 

See details in the full reports

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