AstraZeneca vaccine: risk of death is 1 in a million, but what does that mean?

24 August 2021

 

Text version and sources listed below. Image: Australian Academy of Science; CC2.0. See high resolution version of this image, or download a PDF of this file suitable for printing (12MB).

Note that in Australia the name ‘COVID-19 Vaccine AstraZeneca’ (usually shortened to ‘AstraZeneca vaccine’) is changing to ‘Vaxzevria’ to identify the specific vaccine and match the name used internationally. There is no change to the vaccine itself.

 

 

Text version and sources listed below. Image: Australian Academy of Science; CC2.0. See a high resolution version of this image, or download a PDF of this file suitable for printing (14MB).

Note that in Australia the name ‘COVID-19 Vaccine AstraZeneca’ (usually shortened to ‘AstraZeneca vaccine’) is changing to ‘Vaxzevria’ to identify the specific vaccine and match the name used internationally. There is no change to the vaccine itself.

What is TTS?

Thrombosis with thrombocytopenia syndrome (TTS) is a rare condition reported in some people who have received adenoviral vector COVID-19 vaccines [such as the AstraZeneca COVID-19 vaccine]. The syndrome is characterised by blood clot formation (thrombosis) combined with low platelet levels (thrombocytopenia).

TTS is different to other more commonly diagnosed blood clotting conditions as it is triggered by an immune response that causes the combination of both clots and low platelets.

Having a history of blood clots, like deep vein thrombosis (DVT), does not increase your risk of TTS due to the AstraZeneca vaccine.

Text version and sources for infographics

Infographic 1: If you choose to get the AstraZeneca vaccine, your risk of death from TTS is 1 in a million and your risk of getting TTS at all is less than 30 in a million

Risk of death due to TTS from receiving the AstraZeneca COVID-19 vaccine is 1 in a million

Death linked to the AstraZeneca vaccine (the name is changing to Vaxzevria) in Australia equals approximately 1 in a million. To 29 July 2021, there have been seven fatalities in Australia out of 6.8 million doses of AstraZeneca vaccine. Six deaths are attributed to TTS, with one death being attributed to the even rarer ITP (immune thrombocytopenic purpura). Source: TGA Weekly COVID-19 Vaccine Safety Report, 5 August 2021, accessed 5 August 2021

Risk of TTS from receiving the AstraZenecaCOVID-19 vaccine is less than 30 in a million

TTS is currently estimated to affect about 1–2 per 100,000 people who receive the AstraZeneca COVID-19 vaccine. For those under 60 years of age, the rate is estimated to be higher, about 2–3 per 100,000 people. Therefore at the highest risk group, it is 3 per 100,000 = 30 in a million. Source: Australian Government Department of Health, 2021, accessed 10 August 2021

Risk of death due to rock climbing is 3 in a million

In a 2018 study comparing everyday risks using the measure of mortality per million, rock climbing deaths were recorded as a 3 in a million risk. Source: Macnamara et al. 2019, accessed 9 August 2021

Risk of death from a general anaesthetic is 18 in a million

In Australia, from 2015 to 2017, there were 239 deaths considered anaesthesia-related, and a total of 13,652,911 estimated anaesthesia procedures performed. Source: Australian and New Zealand College of Anaesthetists, Mortality Sub-Committee (2015–2017), accessed 9 August 2021

Risk of death from accidental poisoning is 55 in a million

Accidental poisoning is caused by exposure to an amount of a substance that harms the body. In Australia during 2017–18, accidental poisoning resulted in 5.5 deaths per 100,000 population. Source: AIHW 2021, accessed 9 August 2021

Risk of death from giving birth is 67 in a million

In the decade from 2009 to 2018, the maternal mortality rate was 6.7 deaths per 100,000 women giving birth in Australia. Source: AIHW 2020, accessed 9 August 2021

Risk of death due to daily aspirin is 100 in a million

For 50-year-old men, taking a full-sized, 325 mg aspirin every day to prevent heart disease and stroke carries a risk of 10.4 deaths per 100,000 men per year (over and above their overall death risk). Source: Cohen and Nuemann 2007, accessed 9 August 2021

Risk of being struck by lightning is 2 in a million

The risk of being struck by lightning in any given year is 1 in 500,000, based on data from the CDC in the United States of America (2013), accessed 9 August 2021

Infographic 2: If you choose to get the AstraZeneca vaccine, your risk of death from TTS is 1 in a million and your risk of getting TTS at all is less than 30 in a million

But how small is 1 in a million?

1 minute in 2 years

2 years = 2 x 365 days = 2x 365 x 24 hours = 2 x 365 x 24 x 60 minutes = 1,051,200 minutes

8 cm along the way from Brisbane to the Gold Coast (80 km)

The distance from the Gold Coast to Brisbane in Australia is 79.2 km. 80 km = 80 x 1000 m = 80 x 1000 x 100 cm = 80,000,000 cm. Distance estimate from Google Maps (2021), accessed 9 August 2021

1 person out of 10 sold-out MCG stadiums

The Melbourne Cricket Ground stadium (or MCG) has a capacity of 100,024 people when full. Source: Stadium DB, accessed 9 August 2021

1 single hair out of a total of 10 people’s heads

The number of hairs most healthy people have on their head is between 80,000 to 120,000. Source: Murphrey et al. 2020, accessed 9 August 2021

Size of the orange dot relative to the size of the infographic

When designed, the orange dot was 1.6 x 1.6 pixels in size (2.56 px²). The graphic is a total of 2,605,440 pixels (1357 x 1920 pixels)