Australia’s active vaccine safety system
The world’s largest published post-marketing analysis of COVID-19 vaccines has affirmed the short-term safety of Comirnaty (Pfizer) and Vaxzevria (AstraZeneca) COVID-19 vaccines.
The research, led by AusVaxSafety, analysed data from more than 3 million Pfizer and AstraZeneca COVID-19 vaccine recipients in Australia who participated in active vaccine safety surveillance via the AusVaxSafety system between 22 February 2021 and 30 August 2021. Surveillance is ongoing and now includes almost 6.5 million survey responses, including more than 100,000 from Aboriginal and Torres Strait Islander vaccine recipients.
35.9% of respondents reported at least one adverse event following immunisation (AEFI) in the first 3 days after Pfizer dose 1; 54.7% after Pfizer dose 2; 52.8% after AstraZeneca dose 1; and 22% after AstraZeneca dose 2.
Local pain, fatigue, headache and myalgia were the most frequently reported AEFIs. Reported AEFIs were mostly short-lived, with the proportion of respondents who reported AEFIs in the day 8 surveys lower than in the day 3 surveys.
The rate of AEFIs reported by Aboriginal and Torres Strait Islander peoples was similar to that for other Australians. AusVaxSafety researchers found AEFIs were more frequently reported by women and people with underlying medical conditions, including a history of anaphylaxis.
“After adjusting for demographic characteristics, vaccination site type, jurisdiction and self-reported medical conditions, the odds of reporting any AEFI were higher for women than men, for people with a history of anaphylaxis and for people reporting certain underlying conditions, including obesity, immunodeficiency or chronic inflammatory disease,” said Dr Lucy Deng, clinical lead of the AusVaxSafety program.
Overall, 0.9% of respondents sought medical advice in the 3 days following vaccination, most frequently after Pfizer dose 2 (1.4%) and AstraZeneca dose 1 (1.2%). Similarly, impact of symptoms on daily activities was most frequently reported after Pfizer dose 2 (20.3%) and AstraZeneca dose 1 (17.4%).
Findings were broadly consistent with and reaffirm safety profiles of these vaccines identified in clinical trials and other post-marketing surveillance conducted internationally.
As clinical trials predominantly enrol healthy people, post-licensing monitoring is essential for assessing the ongoing safety of new vaccines. AusVaxSafety continues to monitor COVID-19 vaccine safety in Australia as the Australian vaccination program evolves.
Read the full study here
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