A really important critique of the flawed @AnnalsofIM masks vs respirators trial. Good on
@bmj_latest for publishing it

www.bmj.com/content/393/...

To learn how to see what variants are circulating in your area, please read this guide ( bsky.app/profile/jeff... ). 25/

To learn how to create a Sankey diagram of variants circulating in your area, please read this guide ( bsky.app/profile/jeff... ). 24/

The visualization tool for variants was created by @mikehoney.bsky.social and the source of this data can be found at ( app.powerbi.com/view?r=eyJrI... ). 23/

You can find weekly Ontario stats including variants at ( covid.gilchrist.ca/Ontario.html ). 22/

Sankey diagram showing the evolution of sequenced viral genomes in Ontario, Canada, from February to March 2026.

The SanKey diagram shows you variant lineages and you can follow back where that variant came from. 21/

How do variant designations work and relate to our immunity? How do variant designations work and relate to our immunity? Variants: JN.1 vs KP.2 vs KP.3.1.1 Written by: Jeff Gilchrist & Paul Seaman Link to this document: https://tinyurl.com/VariantsSummer2024 L...

As time goes, keeping track of the virus evolution is getting more complex. You can learn more about how variant naming works and mutations from this document ( docs.google.com/document/d/1... ). 20/

The XFY variant family is a recombinant of XFG.5.1 Stratus and NB.1.7.1 Nimbus, so both of the most common variant families together. 19/

RE.1.2 and RT.2 are part of the BA.3.2.* Cicada family, also known as BA.3.2.2.1.2 and BA.3.2.2.2.2.4.2. Variants PQ.2.1, RC.5, RC.6, and SH.1 are part of the Nimbus family, also known as NB.1.8.1.2.1, NB.1.8.1.2.8.1.5/6 and NB.1.8.1.2.1.3.1. 18/

Line graph showing COVID-19 BA.3.2.* Cicada variant family frequency in Ontario, Canada, from February to March 2026.

Two BA.3.2.* Cicada family variants RE.1.2 sits at 4.7% and RT.2 is currently at 3.9%. 17/

Line graph showing specific COVID-19 variant frequencies in Ontario, Canada, from February to March 2026.

Looking at specific variants, RC.5 levels have dropped but still holds first place at 6.6%, XFG.1.1 made a move but decreased to 6.1% where it is tied with SH.1 then XFG.1.1.2 at 5.5%, followed by RC.6 at 4.7% and PQ.2.1 at 4.1%. 16/

The BA.3.2 "Cicada" family has been fairly steady at 6.6% while the XFY.* family has dropped to 1%. 15/

Line graph showing COVID-19 variant family frequencies in Ontario, Canada, from January to March 2026.

In Ontario, there has been some competition for variant dominance in Ontario during the month of March. The NB.1.8.1.* "Nimbus" family currently holds first place with 53.6% while the XFG.* "Stratus" family sits at 36.5% of sequenced genomes from COVID tests. 14/

Ryan Hisner also did a deep dive on BA.3.2 mutations and why it might behave differently in kids ( bsky.app/profile/ryan... ). 13/

2. Producing illness that is more severe in kids than in adults (so more likely to get tested) which could be:
a) Less severe disease in adults
b) More severe disease in kids
c) Both a) and b) at the same time

12/

Euan Arnott had a good post about possible scenarios ( x.com/Nucleocapsoi... ). While it is clear something different is happening with BA.3.2, we are not sure if this is due to:
1. BA.3.2 more able to infect children

11/

Children now would typically only get PCR tested for COVID if they had a serious enough respiratory illness to be brought to the ED or admitted to hospital. We are missing a large amount of covid test sequences from infected children that might give us a better pictures. 10/

Labs in non-funded pediatric hospitals, while they test for COVID, do not send samples to PHO since there is no current requirement for COVID. 9/

With such few samples and limited testing of COVID it is hard to know why this is the case. Only some hospital labs in Ontario are funded by PHO to do genetic sequencing. 8/

Graph showing percentage of BA.3.2 "Cicada" variant lineage sequences in Ontario by Age Group with a trend going down from kids 5-11 as age groups get older.

...despite older adults, often in long-term care, being the most likely to be tested and sequenced (more than 50% of available sequences):
50% = Age 5-11
21.4% = Age 12-19
20.7% = Age 0-4
17.3% = Age 20-39
9.6% = Age 50-59
4.2% = Age 60-79
2.6% = Age 80+

7/

With only 75 sequences available for BA.3.2.2 so far, we see that the breakdown by age group generally shows decreasing percentages as age increases... 6/

What about Ontario? In PHO's latest April report, this also seems to hold true ( www.publichealthontario.ca/-/media/docu... ). 5/

Variant trackers have noticed an interesting pattern with the BA.3.2 "Cicada" family where the highest proportion of sequences reported have been in children and seems to hold true for all countries reporting age with their COVID sequences. 4/

The youngest age group 0-4 currently have a hospitalization rate due to COVID that are 17x higher than age 5-17, 17x higher than age 18-49, and 2.8x higher than adults 50-64. 3/

Graph of New hospitalization rate in Ontario due to COVID by age group (100% Stacked).

Looking at age groups, those age 75+ had the highest rates of hospitalization due to COVID but decreased since last update. Second place is age 0-4 and their levels are currently increasing while age 65-74 has the third highest rate and also decreased since last update. 2/

Graph of New hospitalizations in Ontario due to COVID, Influenza or RSV.

*** Ontario Virus & Variant Update | Apr 13 ***

Hospitalizations due to COVID have gone down from 153 to 123 in the last update. Influenza hospitalizations decreased from 59 to 47 and RSV decreased from 110 to 85. 🧵1/

#Ontario #Virus #Variant #COVID #RSV #Influenza #Hospital

Recent analysis by several Variant Hunters has confirmed that BA.3.2.* is preferentially infecting children.

For example, here’s a comparison of recent samples from New York. For children, BA.3.2.* is 11% of samples, vs just 1.4% of adults, so around 8X more common.

#COVID19 #SARSCoV2 #Global
🧵

So it's clear that BA.3.2 preferentially infects children, something we have never seen before in a SARS-CoV-2 variant.

Why?

The question's baffled me, but after a suggestion from @darrenmartin.bsky.social, I think I have an explanation that makes sense.
1/16

Quick elaboration on this. The disproportionate rate at which BA.3.2 infects children is not driven by infants. The 0-1 age group is less overrepresented (by a large margin) than the 2-5 and 6-17 age groups in the countries we have data for.
1/4

Exactly... ( bsky.app/profile/jeff... )