With the current focus on COVID-19 vaccines, Healthdirect Australia has developed the COVID-19 vaccine symptom checker to help you decide what to do if you have side effects after a COVID-19 vaccination, ranging from common flu-like symptoms to rare cases when medical attention is needed.
Mild side effects
Evidence from clinical trials, along with national and international databases, show that most side effects being reported after vaccination with AstraZeneca and Pfizer COVID-19 vaccines are mild and temporary (lasting only a few days).12-14
National survey data from over 1,459,000 Australians (information correct to 11 July 2021) who have received either one or both doses of a COVID-19 vaccine shows that for the AstraZeneca vaccine, around 6 in 10 people (55.6%) reported experiencing side effects after the first dose and around 3 in 10 (29.2%) after the second dose.15 For the Pfizer vaccine, this trend was reversed, with 4 in 10 people (37.3%) experiencing symptoms after the first dose and 6 in 10 (57.0%) after the second dose.15
These potential side effects include those described above such as fever, headaches, muscle and joint pain as well as injection site reactions (pain, redness, swelling or hardness where the needle went in). Other possible side effects being described for both vaccines also include nausea and tiredness (fatigue).15
“Usually rest is the best advice for managing mild vaccine-related side effects,” says Dr Samecki.
“If you have a fever, you should stay well hydrated, keep the room at a comfortable temperature, wear lightweight clothing and avoid using warm bedding as it may make you hotter.
“There is no need to take medicines for pain or fever unless you are uncomfortable. However, if you are feeling discomfort, simple pain relievers such as paracetamol
are available over the counter without a prescription and can help reduce pain and fever.
“Before taking any medicine, check the active ingredients are safe to take with any medical conditions you have, other medicines you are taking, or if you are pregnant or breastfeeding,” she says.
When to seek medical attention
New, unexpected or persistent symptoms
Speak with a health professional if you are worried about a potential vaccine side effect, have new or unexpected symptoms, or if you have an expected side effect that hasn’t gone away after a few days.
The COVID-19 vaccine side effects symptom checker can help and you can contact the Adverse Medicine Events line for information about side effects and to forward reports to the TGA. The service is, however, unable to provide medical advice.
Symptoms more than 4 days after vaccination
A very rare condition called thrombosis with thrombocytopenia syndrome (TTS) has been reported as confirmed or probable in 87 Australians who receive their first dose of the AstraZeneca COVID-19 vaccine (information correct to 23 July 2021).16 There have been over 6.1 million doses of the AstraZeneca vaccine given. Australian data show that the risk of this very rare side effect is lower in people that are older. It appears that the condition is also more severe in younger people.17 Current estimates (on 23 July 2021) of risk are summarised in the following table. There are no reports of TTS occuring in Australia following a second dose of AstraZeneca vaccine.
|Age||Estimated risk of TTS for every 100,000 AstraZeneca vaccine first doses given|
|younger than 50 years ||3.3|
|50 - 59 years of age||2.5|
|60-69 years of age||1.5|
|70 - 79 years of age||1.8|
|80 years or older||1.8|
The key signs of this adverse event are blood clotting (thrombosis) and low platelet levels (thrombocytopenia).16 First reports of this rare condition emerged from Europe in April 202118 and medicine regulators both here and overseas continue to monitor the issue and investigate reports of potential events.17 A consequence of this monitoring is that information about the condition continues to grow and there are now established procedures to help treat people who develop this condition. Health professionals are now fully alert to the potential of TTS and are more likely to diagnose it earlier. Raised awareness, early diagnosis and appropriate treatment have meant that most people who experience this extremely rare condition return to good health.16,17
Symptoms for TTS typically occur around 4 to 28 days after vaccination.3 You need to seek medical attention, and if severe, go to a hospital emergency department, if you have any of the following symptoms, particularly 4 to 28 days after vaccination:
- severe, persistent headaches that do not settle with paracetamol or other pain reliever medicines
- blurred vision
- weakness of face (such as slurred speech or drooping mouth or drooping eyelid), or weakness in the arms or legs
- confusion or seizure
- shortness of breath
- chest pain
- persistent abdominal pain
- leg swelling
- rash or bruising not at the injection site that cannot be explained.19
Severe allergic reactions
Serious but extremely rare side effects to vaccines – including the COVID-19 vaccines – can include allergic reactions. If an allergic reaction is going to happen it will usually occur within 15 minutes of receiving a vaccine, which is why you should wait this amount of time before you leave the vaccination centre.
Seek medical attention if you think you are having an allergic reaction and call 000 if the symptoms are severe, such as if you have difficulty breathing, start wheezing, have a fast heartbeat or feel like you may be about to collapse.