Covid19

COVID-19 vaccine weekly safety report – 05-08-2021

Read more at www.tga.gov.au

Since last week’s report, a further 3 reports of blood clots and low blood platelets have been assessed as confirmed or probable TTS likely to be linked to the AstraZeneca vaccine (Table 1).  Sadly, one of the cases, a 34-year-old woman from NSW, died yesterday. The TGA extends its sincerest condolences to her family and loved ones. We are in close communication with NSW Health who are undertaking further investigation of this case.

Table 1: Newly confirmed and probable TTS cases for the week of 30 July – 5 August 2021‡

New confirmed TTS

New probable TTS

Two new cases:

One new case:

As previously reported, the TGA determines whether a report is likely to represent TTS by assessing cases against accepted criteria established by the UK’s Medicines and Healthcare products Regulatory Agency.

In addition to the new cases identified above, one case previously reported as probable was reclassified to confirmed. This takes the total Australian reports assessed as TTS following the AstraZeneca vaccine to 93 cases (57 confirmed, 36 probable) from approximately 6.8 million vaccine doses. 

When assessed against the criteria used by the US Centers for Disease Control and Prevention (CDC), fewer than half of the cases reported to TGA are classified as Tier 1 cases which tend to have more serious outcomes. Tier 1 cases involve clots in an unusual location, such as the brain or abdomen (Table 2). 

In Australia, severe cases of TTS appear to be more common in women in younger age groups. Nearly half of the TTS cases in women required treatment in intensive care. Cases meeting the criteria for Tier 1 were also twice as likely to occur in women compared to men. Five of the 6 deaths occurred in women aged 34, 48 (2 cases), 52 and 72-years-old. The other death was in a 44-year-old man.  

Table 2: Total confirmed and probable TTS cases to date by age and CDC classification

Age

Total cases

CDC classification†

Tier 1

Tier 2

Not classified

<30 years

1

1

30-39

2

2

40-49

6

6

50-59

23

11

7

5

60-69

22

8

6

8

70-79

28

8

8

12

80+

11

3

4

4

All ages

93

(42 men, 51 women)

38

26

29

† The US CDC classification is defined as:

  • Tier 1 = clots in an unusual location (such as the brain or abdomen) and a low platelet count with or without antibodies that activate platelets (anti-PF4 antibodies)

  • Tier 2 = clots found in common locations (such as the leg or lungs) and a low platelet count and anti-PF4 antibodies

  • Not classified = case does not meet the criteria for Tier 1 or Tier 2 (for example clots in common locations with low platelet count but no evidence of anti-PF4 antibodies).

Cases have most often occurred about 2 weeks after vaccination, although the time to onset (or diagnosis) has ranged from one to 54 days (Table 3). 

Table 3: Time to onset, treatment and outcomes for TTS cases*

Time to onset/ diagnosis (days)

Median (range)

12 (1-54)

Treated in ICU

At any point

29

Currently

4

Outcome

Discharged

72

In hospital

15

Fatal

6

*Data is based on the most recent medical information available to the TGA

Read more at www.tga.gov.au

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