More than 60 million doses of COVID-19 vaccines have now been administered in Australia. The safety of these vaccines is monitored on an ongoing basis and while there are some commonly reported side effects, reports of serious side effects are extremely rare.
 

Common side effects

Like all medicines used in Australia, COVID-19 vaccines can cause mild side effects, but not everyone gets them. Most side effects are mild and short-lived, with the vast majority of people affected recovering within 3 days. Common side effects include:

  • pain at injection site
  • feeling tired
  • headache
  • aches and pain
  • fever and chills

You can take pain relief medication such as paracetamol to help relieve these symptoms.

Access the latest COVID-19 vaccine short-term common side effects data here

It can take up to 12 days after the first dose of the vaccine for your body to produce antibodies to partially protect you, and 7–14 days after the second dose to reach the optimal level of protection provided by the vaccine. You cannot catch COVID-19 from getting your vaccine; however, if you develop COVID-19-like symptoms any time after your vaccination, it is important that you still get tested and follow public health advice. A booster dose is recommended 3 months after your second dose to make sure the protection from the first 2 doses is even stronger and longer lasting.
 

Extremely rare side effects

Serious or allergic reactions to vaccines are extremely rare. Although serious allergic reactions usually occur within 15 minutes of receiving a vaccine, there are some very rare conditions that have been linked to COVID-19 vaccines that can occur later after vaccination.
 

Blood clots (Thrombosis with thrombocytopenia syndrome – TTS)

Thrombosis with thrombocytopenia syndrome (TTS) has been found to be causally associated with the AstraZeneca COVID-19 vaccine. This condition is very rare, with 2 cases out of every 100,000 people after a first dose AstraZeneca vaccine and 3 cases out of every million people after a second dose of  AstraZeneca vaccine reported in Australia.

TTS involves the formation of blood clots (thrombosis) by platelets in body places where blood clots should not occur, such as the brain, abdomen, chest and legs, preventing blood flowing normally through those parts of the body. Because the platelets are used up in the formation of these clots, it leads to a decrease in platelets (thrombocytopenia) in the bloodstream, preventing them from doing their normal function. Thrombocytopenia can lead to excessive bleeding if blood cannot form clots where it is needed.  

Symptoms of TTS most commonly develop 4 to 30 days after an adenovector viral vaccine such as the AstraZeneca vaccine. The condition is not found to be associated with mRNA vaccines such as Pfizer and Moderna vaccines. 

Early treatment for TTS can prevent serious complications. It is therefore important for people with early symptoms of TTS to get medical attention as soon as possible. Contact your doctor or healthcare professional as soon as possible or go directly to a hospital if you have:

  • severe or persistent headache that does not go away after taking pain relief medication
  • blurred vision, loss of power or sensation, confusion or seizures
  • shortness of breath
  • abdominal pain that does not go away after taking pain relief medication
  • chest pain
  • leg pain or leg swelling
  • unusual bruising or pinpoint spots (petechiae) on skin that can not be explained from trauma.

More detailed information on TTS is available at the links below:

Heart inflammation (myocarditis and pericarditis)

In rare instances, myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the outer lining of the heart) have been reported by individuals after receiving an mRNA COVID-19 vaccine – Pfizer or Moderna. 

Most cases typically happen within 10 days of vaccination and occur more commonly after the second dose in men aged under 30 years. Most people have mild symptoms and recover well. In Australia, 1–2 cases out of every 100,000 people after receiving the Pfizer vaccine have been reported.

Contact your doctor or healthcare professional as soon as possible or go directly to a hospital if you have:

  • chest pain
  • pressure or discomfort in the chest
  • irregular, skipped heartbeats or ‘fluttering’
  • fainting
  • shortness of breath
  • pain when breathing.

More detailed information on myocarditis and pericarditis is available at the links below:

COVID-19 Vaccine Side Effects Symptom Checker

If you think you may be experiencing side effects following your COVID-19 vaccination, you can check these and get information on what to do next on the healthdirect COVID-19 vaccine Side Effects Symptom Checker below.

healthdirect COVID-19 vaccine Side Effects Symptom Checker
 

Last updated May 2025