Thread by @miamalan

[Thread] 1. Why are #Omicron infections in SA decreasing slower than what they increased?
@Dr_Groome of @nicd_sa:
1. 4th wave’s downward slope = plateaued. We’ve had similar nrs of new #COVID19 cases for 3 weeks
2. 4th wave downward slope (graph) = not as steep as upward slope

2. Is the number of #COVID19 infections per 100 000 people increasing in any province?

1. Yes, it's increasing in MP, FS, GP, LP (if we compare the past 7 days with the previous 7 days)
2. In coastal provinces (WC, KZN, EC) cases are decreasing

3. Is the % of #COVID19 tests coming out positive (test positivity rate) increasing in any province?

1. Yes, over the past 3 weeks the test + rate has increased in GP, FS, MP, LP (black line on graph)
2. But the test + rate declined in coastal provinces (WC, EC, KZN) and NC.

4. In which age groups are increases in new #COVID19 cases and the % of people testing positive occurring?

Mainly in those younger than 20 years

5. So why are the increases in some provinces happening and why are new #COVID19 cases not going down?
Possible reasons:
1. There’s a new variant or lineage of #Omicron circulating
2. There are changes in behaviour or exposure, e.g. the opening of schools

6. Is there a new #COVID19 variant?

1. Not an entirely new variant, but an #Omicron subvariant that has been identified in about 60 countries
2. It has been circulating in SA for 2 months. It’s called BA.2 or 21L (the original Omicron lineage = called BA.1)

7. If BA.2/21L has been around in SA for 2 months, why are we only concerned about it now? Because it's occurrence is increasing.

1. 99.1% of #COVID19 cases in SA are caused by #Omicron
2. In Dec, 4% of tests analysed = BA.2/21L
3. In Jan, 23% of tests analysed = BA.2/21L

8. Why could BA.2/21L potentially be contributing 2 more #COVID19 infections?

Data from Denmark + UK suggest = more transmissible than #Omicron BA.1 (original form), so it spreads faster + infects more people. No indication that it makes people sicker: bit.ly/3Lupqlx

9. Should we be worried?
@Dr_Groome:

We don’t yet have enough data to be concerned, but SA is monitoring the spread of BA.2 and is now collecting larger numbers of test samples to analyse in provinces where infections are increasing (so in MP, GP, LP, FS, NW)

10. Why are we specifically seeing upticks in infections in people younger than 19?

@Dr_Groome:
1. Schools have opened
2. Why do we see increases in northern provinces but not coastal provinces? Schools in coastal provinces opened later, so increases = likely in the next weeks

11. Why could the opening of schools have led to more #COVID19 infections?
1. More people = gathered indoors (it increases the risk 4 infection)
2. Fewer young people than older people = vaxxed/previously infected (so they have lower levels of immunity)

12. @Dr_Groome:

1. Increases in school kids = not unexpected (schools were closed for most of the 4th wave and now opened - we saw a similar picture during the 3rd wave)
2. We need to encourage vaccination in people between 12 and 17 years of age

13. What’s happening with hospital admissions?

Past 2 weeks:
1. On a provincial level, hospitalisations = declining
2. On a district level, there are increases in 15 districts, eg. City of Tshwane (where SA's #Omicron outbreak started)

14. Who is getting admitted to hospital?
Waasila Jassat, @nicd_sa:

1. Mainly people of younger than 30, particularly school-going children (so it corresponds to the higher nr of current infections in that group)
2. Mainly unvaccinated people

15. How does SA’s #COVID19 deaths in vaxxed vs. unvaxxed people compare 2 the US where the vaxxed pop = larger than the unvaxxed pop (SA = the opposite)?

@ProfAbdoolKarim:
CDC analysis:
Death rate in US = 13-fold higher in unvaxxed people vs. those with 2 vax doses