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5/ However, PJ.2.1 should be closely monitored for the emergence of mutations that increase antibody evasion, as previously suggested by others.

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4/ Overall, increased ACE2 binding may be a key driver of PJ.2.1 transmission. PJ.2.1 was robustly neutralized by antibodies induced by LP.8.1- and XFG-adapted mRNA vaccines, suggesting that vaccination should provide protection.

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2/ Despite its highly mutated spike protein, PJ.2.1 did not show increased evasion of antibodies from donors vaccinated with the LP.8.1-adapted mRNA vaccine.

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Stefan Pöhlmann @snpoehlm.bsky.social · 12/10/2026

We analyzed cell entry and antibody-mediated neutralization of the emerging saltation variant PJ.2.1. Check out our preprint below! #PJ21 1/ We found that PJ.2.1 shows increased ACE2 binding and enhanced entry into cells expressing low levels of ACE2.

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PJ.2.1 also detected in France 🇫🇷. 1 sequence, collected September 1

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Stefan Pöhlmann @snpoehlm.bsky.social · 12/10/2026

PJ.2.1 has reached New Zealand 🇳🇿 and Israel 🇮🇱. New Zealand: 3 sequences, all collected in late September Israel: 1 sequence, collected in late August #PJ21

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Reposted by Stefan Pöhlmann

Ryan Hisner @ryanhisner.bsky.social · 09/10/2026

Just to add some detail to the PJ.2.1 picture outlined in the thread below, here's a Venn diagram (modeled on Cov-Spectrum's) of the four major PJ branches' amino acid mutations (excluding all shared, inherited MC.10.1.7 mutations).

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Reposted by Stefan Pöhlmann

Ryan Hisner @ryanhisner.bsky.social · 09/10/2026

Large upload from Ontario yesterday, providing some striking revelations about the evolution of PJ.2.1. First, there is yet another strikingly divergent branch of PJ.2.1. This isn't one variant: it's four. More and more, this resembles the emergence of BA.1/2/3. What is happening? 1/

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@ryanhisner.bsky.social - are there any mutations in these subvariants that you find interesting and that might warrant functional analysis? Thanks! #BA32

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➡️RD* and SN* stood out: they showed either no such age preference or a much less pronounced one. However, data for these subvariants remain limited.

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➡️RE* had the most entries (998) and showed the expected age preference, with children aged 0-9 preferentially infected. Most other subvariants showed a broadly similar pattern.

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We demonstrated that BA.3.2 preferentially infects children aged 0-9. However, our initial analyses did not examine BA.3.2 subvariants separately. Here are the additional results, based on all BA.3.2 sequences deposited in GISAID in 2026:

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The good news: vaccination boosted neutralizing responses against many currently circulating variants, including the emerging saltation variant PJ.2.1 The less good news: neutralizing antibodies against BA.3.2 showed the weakest boost. #BA32 #PJ21

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Effects of XFG-adapted mRNA vaccination on SARS-CoV-2 variant neutralization - see our new preprint. Georg Behrens, Markus Hoffmann & teams analyzed neutralizing antibody responses in individuals who received an XFG-adapted mRNA booster, recommended for the 2026/2027 COVID season.

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Ryan Hisner @ryanhisner.bsky.social · 07/10/2026

New sequences from Saitama and Yamanashi, Japan 🇯🇵, collected from June through September: over 70% are BA.3.2 Looking at September alone, nearly 60% are BA.3.2 As others have noted, the frequency of BA.3.2 in Japan remains unexpectedly high. #BA32

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Reposted by Stefan Pöhlmann

There was also a partial PJ.2.1 sequence recently in German wastewater.

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Reposted by Stefan Pöhlmann

Ryan Hisner @ryanhisner.bsky.social · 06/10/2026

Since Aug 31, 12.8% (10/78) airport surveillance seqs from international travelers to the US have been PJ.2.1. 45% (9/20) from Latin American travelers in that period are PJ.2.1: 4 from Cuba & 1 each from Chile, Colombia, the DR, Ecuador, & Guatemala. PJ.2.1 is the fastest variant in the world now.

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Stefan Pöhlmann @snpoehlm.bsky.social · 07/10/2026

New sequences from Germany 🇩🇪, all collected in September. No PJ.2.1 - so far. #PJ21

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Stefan Pöhlmann @snpoehlm.bsky.social · 07/10/2026

In Thailand, as in all other countries analyzed, BA.3.2 is most frequently detected in the 0-9 age group. For XFG and other variants (i.e. not XFG*, not NB.1.8.1*), this age group is also the major target but the preference is not as pronounced as that displayed by BA.3.2. #BA32

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Stefan Pöhlmann @snpoehlm.bsky.social · 07/10/2026

BA.3.2 is receding to very low levels in several countries - but not in Thailand 🇹🇭, where its frequency has remained substantial since week 23. This development warrants monitoring, as suggested by @siamosolocani.bsky.social

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Stefan Pöhlmann @snpoehlm.bsky.social · 29/09/2026

New sequences from Japan and South Korea, collected from July through September. BA.3.2 is still circulating at significant levels, accounting for 65% and 28% of sequences, respectively. #BA32

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Stefan Pöhlmann @snpoehlm.bsky.social · 26/09/2026

Importantly, even in Africa’s much younger population, the age preference of BA.3.2 clearly differs from that of other variants (data 01/2026-09/2026):

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Stefan Pöhlmann @snpoehlm.bsky.social · 26/09/2026

We previously found that #BA32 preferentially infects children aged 0-9 years. Our analyses focused on Europe, North America, Asia, and Australia, where the median population age is substantially higher than in Africa.

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Stefan Pöhlmann @snpoehlm.bsky.social · 25/09/2026

My final update for today: 9 new PJ.2.1 sequences: 🇺🇸 7 from the US 🇪🇸 2 from Spain At first glance, no new A475V cases - but @ryanhisner.bsky.social might well correct me here.

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Stefan Pöhlmann @snpoehlm.bsky.social · 25/09/2026

4 out of 50 new sequences from Syracuse, NY, USA, are PJ.2.1 #PJ21 Patients are in age groups 0-9 and 65+

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Stefan Pöhlmann @snpoehlm.bsky.social · 25/09/2026

One new PJ.2.1 from Spain 🇪🇸 The sample was collected from a one-month-old, non-hospitalized male in Vitoria-Gasteiz, northern Spain. Among 90 newly submitted sequences - many collected in September - only one was PJ.2.1. Its spread may therefore be less robust than initially persumed. #PJ21

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🙏 Thanks to everyone who contributed links and resources. My apologies to anyone whose suggestions I may have overlooked.

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🇺🇸 USA 𓆞 Lungfish lung.fish 𓆞 Lungfish Wastewater Data Explorer lungfish-science.github.io/wastewater-d... WastewaterSCAN data.wastewaterscan.org CDC – Traveler-Based Genomic Surveillance (TGS) cdc.gov/traveler-gen...

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🇹🇭 THAILAND Department of Disease Control Dashboard dvis3.ddc.moph.go.th/t/DDC_CENTER... 🇹🇼 TAIWAN Taiwan CDC – Surveillance cdc.gov.tw/Category/Pag... 🇬🇧 UNITED KINGDOM UKHSA COVID Dashboard ukhsa-dashboard.data.gov.uk/respiratory-... RCGP Research & Surveillance Centre rcgp.org.uk/representing...

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🇸🇪 SWEDEN Swedish Pathogens Portal – SARS-CoV-2 Wastewater Surveillance pathogens.se/dashboards/c... 🇨🇭 SWITZERLAND BAG/FOPH – Communicable Diseases Information Portal idd.bag.admin.ch/de/diseases/... ETH Zürich – WISE Wastewater Surveillance wise.ethz.ch?page=overview

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🇿🇦 SOUTH AFRICA SAMRC – SARS-CoV-2 Wastewater Surveillance Weekly Reports samrc.ac.za/wbe/weekly.h... NICD Wastewater/Genomics Data github.com/NICD-Wastewa... 🇰🇷 SOUTH KOREA KDCA – Infectious Disease Surveillance dportal.kdca.go.kr/pot/bbs/BD_s...

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🇸🇬 SINGAPORE Weekly Infectious Diseases Bulletin cda.gov.sg/resources/we... 🇪🇸 SPAIN SiVIRA – Respiratory Virus Surveillance docsivira.isciii.es/Informe_sema... 🇪🇸 CATALONIA SIVIC – Respiratory Infections / COVID-19 sivic.salut.gencat.cat/covid

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🇳🇿 NEW ZEALAND Wastewater Surveillance esr-cri.shinyapps.io/wastewater/ 🇵🇱 POLAND – WARSAW MPWiK Warsaw – SARS-CoV-2 Wastewater Surveillance mpwik.com.pl/view/monitor... 🏴 SCOTLAND Public Health Scotland – Respiratory/COVID-19 Surveillance scotland.shinyapps.io/phs-respirat...

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🇱🇺 LUXEMBOURG MicrObs – SARS-CoV-2 microbs.lu/dashboards/r... 🇲🇽 MEXICO Weekly Influenza, COVID-19 & Respiratory Virus Surveillance gob.mx/salud/docume... 🇳🇱 NETHERLANDS RIVM – Weekly COVID-19 Update rivm.nl/en/coronavir...

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🇯🇵 JAPAN Ministry of Health – COVID-19 Surveillance mhlw.go.jp/stf/seisakun... 🇯🇵 SAPPORO Sapporo City – SARS-CoV-2 Wastewater Surveillance city.sapporo.jp/gesui/survei... 🇯🇵 YAMANASHI Yamanashi Prefecture – Wastewater Surveillance pref.yamanashi.jp/kansensho/ge...

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🇮🇹 ITALY ISS – SARS-CoV-2 Surveillance epicentro.iss.it/coronavirus/... ARPA Piemonte – Wastewater Variant Sequencing arpa.piemonte.it/scheda-infor...

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🌍 GLOBAL Pandemic Mitigation Collaborative (PMC) pmc19.com/global 🇭🇰 HONG KONG Government COVID-19 Portal / Archive coronavirus.gov.hk/eng/index.html 🇮🇪 IRELAND HPSC – Respiratory Virus Notification Data Hub respiratoryvirus.hpsc.ie

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🇩🇪 GERMANY RKI Infection Radar – Wastewater infektionsradar.rki.de/en/covid/sew... RKI – SARS-CoV-2 Sublineages public.data.rki.de/t/public/vie... 🇩🇪 GERMANY & 🇺🇸 USA World Health Network – Wastewater-based infection estimates whn.global/estimation-o...

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🇨🇦 ONTARIO Public Health Ontario – SARS-CoV-2 Genomic Surveillance t.co/m6NkwH9iRC 🇨🇳 CHINA China CDC – SARS-CoV-2 Surveillance chinacdc.cn/jksj/jksj04_... 🇫🇷 FRANCE Santé publique France – COVID-19 Surveillance santepubliquefrance.fr/covid-19/don...

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🇨🇦 ALBERTA Respiratory Virus Dashboard – variants & wastewater alberta.ca/stats/dashbo... 🇨🇦 BRITISH COLUMBIA BCCDC – Wastewater Surveillance reporting.bccdc.ca/wastewater_s... BCCDC – Genomic Surveillance reporting.bccdc.ca/genomic_surv...

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🇨🇦 CANADA National Wastewater Monitoring of Pathogens health-infobase.canada.ca/wastewater/ Canadian Wastewater Surveillance wwater.ca COVID Hazard Index covid19resources.ca/covid-hazard... COVID-19 Statistics – Jeff Gilchrist gilchrist.great-site.net/jeff/COVID-1...

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