Dominik Steiger
#Covid wave in #Singapore, update until week 21 2025.
SARS2 positivity among ARI and ARI cases have slightly risen.
Will be interesting to see if the MOH will publish new case and hospitalisation data.
#Singapore MOH public epi surveillance data and #Covid wave press releases:
Data: https://www.cda.gov.sg/resources/weekly-infectious-diseases-bulletin-2025
Press Release May 18 2024: https://www.moh.gov.sg/newsroom/update-on-covid-19-situation
Press Release May 13 2025:
https://www.moh.gov.sg/newsroom/update-on-covid-19-situation-
According to the press release metric, the peak might be nigh.
#Singapore #Covid wave, update until week 22 2025.
Perhaps we've indeed passed the peak.
New seq data (last seq date May 16): No change to the conclusion that NB.1.8.1* cannot have driven this wave.
#Singapore #Covid wave, update until week 23 2025.
Seems to have peaked.
New seq data (last seq date May 27): No change to the conclusion that NB.1.8.1* cannot have driven this wave.
NB.1.8.1* has reached ca. 50% in the presumptive peak week 21 according to the covSPECTRUM estimate.
This wave has likely been smaller compared to the one exactly one year ago. MOH has not published peak week hospitalisation numbers or indeed complete data, AFAIK, so it's hard to compare well.
NB.1.8.1* fraction growth seems to be slowing already (upper figures from covSPECTRUM).
XFG* (lower figures, only 28 sequences) seems to be growing fast, currently still at low fraction size.
We'll see what impact it will have on the currently steeply lowering ARI numbers.
P.S. If this will proceed along above lines, I will have successfully established the Singapore Covid Press Release Metric as a reliable wave peak indicator.
A plausibility check:
Applying the UKHSA Winter CIS IHR (0.45%, https://bsky.app/profile/dominiksteiger.bsky.social/post/3knnplfebjl2b) to the MOH hospitalisation figures:
100 average daily - 7d /100k incidence 12 - 7d /100k infection incidence 2'600
200 average daily - 7d/100k incidence 24 - 7d /100k infection incidence 5'300
Such incidences would be in the order of magnitude range independent measurements and estimates yield for Covid waves.
#Singapore #Covid wave, update until week 24 2025.
The wave has peaked, as expected.
No new seq data that would change the conclusion that NB.1.8.1 has not driven initial growth.
"Nimbus" reached 50% at the peak. Growth started long before it reached significant fraction size.
#Singapore #Covid wave, update until week 27 2025.
The recent fast rise of XFG* is slowing the decline.
We will see if it can drive prevalences up.
I continue to not see that NB.1.8.1* has driven the wave. It reached 50% shortly before the peak.
See also:
https://swiss.social/@dominiksteiger/114716297628001828
Seq data up until July 1st shows NB.1.8.1* in decline (left). The wave peaked in May.
Seq data for XFG* (right).
https://cov-spectrum.org/explore/Singapore/AllSamples/Past6M/variants?nextcladePangoLineage=XFG*&
See also:
https://swiss.social/@dominiksteiger/114680528689524947
Cf. Switzerland:
Not much of a wave so far, in contrast to Singapore. Recently lowering prevalences, despite XFG* fraction becoming dominant end of May. NB.1.8.1* looking less competitive.
Singapore Covid wave, update until week 28 2025.
The recent fast rise of XFG* continues to slow the decline.
As with last week's data: We will see if it can drive prevalences up.
Singapore Covid wave, update until week 29 2025.
XFG* fraction growth has already stalled beginning of July. Its fast growth could not drive a rise.
Seq data from covSPECTRUM until July 15.
As for NB.1.8.1* before: Currently, population immunity, not variant drift, dominates trajectories.
NB.1.8.1* fraction size had reached ca. one third of sequences in week 18, beginning of May, at the peak of ARI cases.
Covid in Singapore until week 31 2025.
The wave is over. Lowest SARS2 positivity (3%) since February.
XFG* could only slow the decline.
This is now the 2nd year when the Singapore wave preceded trajectories in Europe and North America, its wave occurring quite precisely one year after the last
#Covid in #Singapore until week 32 2025.
The last wave (https://www.moh.gov.sg/newsroom/update-on-covid-19-situation-) was likely milder than the one 1 year ago. Note the large influenza wave, too.
It was not variant-driven, as evident from integrating the available sequencing data with the Singapore epi monitoring data.
1/3
Similarly, NB.1.8.1* ("Nimbus") and XFG* ("Stratus") reaching strong dominance could not drive up prevalences a lot in Switzerland.
As per mid July, they comprised about 80% respectively 100% of the viral load in the two plants shown, and similarly elsewhere.
2/3
The data suggest that trajectories are currently rather driven by the number of susceptibles (i.e., the state of population immunity), seasonal, and behavioral factors, not by variant replacement.
3/3
#Covid in #Singapore until week 33 2025.
Acc. to the seq data from covSPECTRUM, XFG* is already falling, after failing to have much of an impact. Some NB.1.8.1* derivative(s) seem(s) to have started rising. I doubt that it will make a large difference to the trajectory.
#Covid in #Singapore until week 34 2025.
Currently needs to be called "influenza in Singapore".
SARS2 positivity among ARI very low (4%), influenza positivity among ILI (23%) highest since Feb. Rising ARI cases will likely be due to influenza, not Covid.
#Singapore, epi data until week 35 2025.
As evident last week: Influenza wave.
Covid XFG* fraction continues to hover around 2/3 of specimens, at low absolute prevalence. The wave was over in week 31.
#Singapore, data until week 36 2025.
Flu wave continues.
Lowest SARS2 positivity among ARI (2%) since I follow this (wk 9 2024).
#Singapore data until week 37 2025.
Flu wave continues.
Very high influenza positivity among ILI. SARS2 positivity among ARI stays very low.
Source: https://www.cda.gov.sg/resources/weekly-infectious-diseases-bulletin-2025
#Singapore #Covid and #Influenza, data until week 39 2025.
Substantial influenza wave.
As you can see from following this thread since March 2024, the Singapore ARI ILI epidemiological surveillance system allows to accurately follow Covid and influenza waves and to early detect onsets of such waves.
Wk. 34 was ending August 24th. Compare to this article from September 8th:
"A sharp rise in flu cases in Singapore has raised concerns among healthcare professionals"
#Singapore #Covid and #Influenza, data until week 41 2025.
Influenza wave continues. Covid at baseline levels.
#Singapore #Covid and #Influenza, data until week 42 2025.
Influenza wave continues, with lowering ILI positivity.
Covid at baseline levels.
Singapore, data until week 44 2025.
Might be over the peak of the H3N2 wave now.
Covid at baseline levels.
#Singapore #Covid and #Influenza, data until week 46 2025.
H3N2 wave coming down.
Covid positivity among ARI lowest since I follow ("<1%").
#Singapore #Covid and #Influenza, data until week 48 2025.
H3N2 wave going sideways.
Covid positivity among ARI lowest since I follow (3 weeks with 2x <1% and 1x 1%).
#Singapore #Covid and #Influenza, data until week 52 2025.
Not clear what drives the pronounced spike in ARI cases in wk52. Covid positivity in the community among ARI lower than ever. Flu positivity among ILI in the community lower than previous weeks. A year end artifact?
#Singapore #Covid and #Influenza, data until week 3 2026.
Singapore, data until week 3 2026
High ARI numbers, despite flu coming down and Covid very low, a pattern never seen since I follow. Which viruses cause this?
#Singapore #Covid and #Influenza, data until week 4 2026.
Very high ARI numbers, now even more detached from Covid and influenza.
What is it?
Covid stays very low, despite a new variant (RF.5) becoming dominant.
#Singapore #Covid and #Influenza, data until week 5 2026
Polyclinic attendances for ARI over the 90th percentile for the 3rd week, without Covid and influenza. What is it? Rhinovirus/enterovirus?
Maybe bad air quality:
"Some clinics have seen up to 25 per cent more patients with coughs and breathing problems, though doctors remain cautious about definitively linking all cases to poor air quality"
#Singapore #Covid and #Influenza, data until week 6 2026
No Covid, no influenza, polyclinic attendances for ARI remain over the 90th percentile.
"Doctors see surge in respiratory cases as haze persists over parts of Singapore"
#Singapore #Covid and #Influenza, data until week 8 2026:
No Covid, no influenza, polyclinic attendances for ARI remain over the 90th percentile. Still the haze? Any better idea?
#Singapore #Covid and #Influenza, data until week 9 2026.
Sources:
https://www.cda.gov.sg/resources/weekly-infectious-diseases-bulletin-2026/
https://cov-spectrum.org/
#Singapore #Covid and #Influenza, data until week 13 2026.
Low ARI activity after the potential haze event. SARS2 positivity slightly higher than previously.
Acc. to Xu Zou (figure, https://x.com/xz_keg/status/2038652822363771213?s=20), RF.5 was dominant in the first half of March, to no big effect.
Also, when searching for Xu Zou's post, I regrettably learned that caning is a thing in Singapore.
