Thread by @miamalan

[Thread] BREAKING 1. Real-world @Discovery_SA data on how well #Pfizer's two-dose #COVID19 jab works in SA:

14 days to 3 months after taking the 2nd shot: :
- 94% effectiveness @ COVID-related death
- 92% effectiveness @ COVID-related hospitalisation

2. What is real-world effectiveness?

It’s data from an actual vaccine roll-out. During studies jabs = used under tightly controlled conditions. In the real world those conditions = more fluid. Real-world data = how well jabs work outside of a trial.

3. Is there a difference between the protection offered by 1 dose of the #Pfizer jab and 2 doses?

Yes.

- 1 dose = 78% effective @ hospitalisation (28 days after you’ve had a jab)
- 2 doses = 94% effective @ hospitalisation (14 days after the 2nd jab)

4. How did @Discovery_SA collect + analyse data?

1. They used the same method scientists use to measure how well influenza jabs work.
2. It’s called a test-negative design study (comparing the vaccination status of people with +#COVID19 tests to those with -#COVID tests).

5. Where does @Discovery_SA’s data come from?

All the data is from Discovery Health medical aid members collected between 17 May (start of #VaccineRollOutSA) and 23 Sep.

They analysed:
- 526,516 #COVID19 tests
- 14,673 #COVID hospital admissions
- 3,441 COVID deaths

6. Does the sex of a fully vaccinated person influence how likely they are to get hospitalised because of #COVID19?

No. Vaccinated men and women (of 18+) are equally likely to get admitted (or not admitted) to hospital.

7. Do specific chronic conditions (comorbidities, e.g. #HIV, #diabetes) influence how likely a fully vaccinated person is to get hospitalised because of #COVID19?

No, but what does matter is how MANY chronic conditions a person has (see next tweet).

8. Does the nr of chronic conditions (comorbidities) that a fully vaccinated person has influence how likely they are to get hospitalised?

Yes. People with 3 or more conditions are more likely to fall seriously ill with #COVID and be admitted to hospital.

9. How does AGE influence how likely a fully vaccinated person is to be hospitalised because of #COVID19?

People of 80+ are most likely to get admitted — but even for older people, the risk remains relatively low (protection = 88% for 80+ vs. 92-94% for all 18+).

10. Did the effectiveness of the #Pfizer jab wane over a period of 3 months (the data interval looked at)?

No. Studies that will look at waning immunity over longer periods of time in SA are being conducted.

11. Do #Pfizer jabs give people who've had #COVID19 more protection than they'd have if they relied on natural immunity only?

YES.

If you’ve had COVID + fully vaccinated, your risk of hospitalisation = 98% reduced. If you rely on natural immunity only your risk = 85% reduced.