This weekly update covers recent developments in vaccine research, including regulatory decisions, clinical trial progress, early- and late-stage data releases, and platform expansion efforts across infectious diseases.
In Today’s Newsletter
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🫁 GSK expands Arexvy approval in Japan [1] [Japan • 22 May 2026]
https://www.gsk.com/en-gb/media/press-releases/gsk-s-rsv-vaccine-arexvy-receives-expanded-approval-in-japan-for-adults-aged-18-59-at-increased-risk/
Context: Labeling now explicitly includes immunocompromised patients as an at-risk group; approval was supported by Phase IIIb immunogenicity and Phase IIb data.
Key point: Arexvy (GSK; RSV vaccine) received expanded approval in Japan for adults aged 18–49 at increased risk for RSV disease.
Implication: May influence prescriber choice and payer reviews pending full data.
🧬 Korea and US groups advance hantavirus vaccine programs [2] [South Korea, US • 17 May 2026]
https://www.dongascience.com/en/news/77872
Context: Remaining preclinical studies are underway with a target to enter Phase 1 testing in 2028; US groups also reported Andes virus DNA vaccine Phase 1 findings.
Key point: Korea University researchers completed animal studies for an mRNA hantavirus vaccine candidate targeting Hantaan and Seoul viruses.
Implication: Signals pipeline investment and modality expansion.
💉 Pfizer advances 25-valent pediatric pneumococcal vaccine [3] [US • 21 May 2026]
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-advances-pivotal-pediatric-pneumococcal-vaccine
Context: Pfizer initiated a pediatric Phase 3 program evaluating a four-dose schedule in up to 2,400 children; no major safety concerns were reported.
Key point: Pfizer reported positive Phase 2 data for PF-07872412 (25vPnC), including higher serotype 3 immune responses versus PREVNAR 20 in infants.
Implication: May influence prescriber choice and payer reviews pending full data.
🌍 WHO recommends LP.8.1 COVID-19 vaccine antigen [4] [Global • 16 May 2026]
https://www.who.int/news/item/16-05-2026-statement-on-the-antigen-composition-of-covid-19-vaccines
Context: WHO reviewed variant evolution, neutralization data, vaccine effectiveness findings, and emerging data on JN.1-descendant and BA.3.2 lineages.
Key point: WHO TAG-CO-VAC recommended monovalent LP.8.1 as the preferred COVID-19 vaccine antigen composition for updated vaccines.
Implication: Could inform regulatory, manufacturing, and vaccination strategy decisions globally.
🛡️ HDT Bio moves CCHF vaccine into Phase 1 [5] [US • 21 May 2026]
https://www.prnewswire.com/news-releases/hdt-bio-and-utmb-receive-mcdc-innovation-prototype-award-for-advancing-cchf-vaccine-from-lab-to-phase-1-clinical-trial-302778410.html
Context: Preliminary Phase 1 data reportedly showed safety and immunogenicity; the candidate uses HDT Bio’s LION delivery platform.
Key point: HDT Bio and UTMB received an MCDC award for advancing HDT-321, a Crimean-Congo hemorrhagic fever vaccine candidate, into Phase 1 testing.
Implication: Signals pipeline investment and modality expansion.
🧪 FDA schedules advisory review for Moderna flu vaccine [6] [US • 21 May 2026]
https://www.reuters.com/business/healthcare-pharmaceuticals/us-fda-hold-expert-committee-meeting-review-modernas-flu-vaccine-2026-05-21/
Context: Moderna amended its application after earlier FDA concerns regarding the comparator flu vaccine used in studies.
Key point: FDA scheduled a June 18 advisory committee meeting to review Moderna’s investigational mRNA seasonal influenza vaccine.
Implication: Could inform future adoption of mRNA-based influenza vaccines pending regulatory review.
Why it matters
- RSV vaccine eligibility continues to broaden into younger at-risk adult populations, reflecting growing focus on chronic disease-associated respiratory risk.
- Pneumococcal vaccine competition is increasingly centered on expanded serotype coverage and improved serotype 3 immunogenicity.
- WHO’s LP.8.1 recommendation may shape upcoming COVID-19 vaccine manufacturing and procurement cycles.
- Emerging-pathogen vaccine development remains active across hantavirus and CCHF programs, supported by biodefense and public-health funding.
- FDA review activity around Moderna’s flu vaccine highlights continued regulatory scrutiny of mRNA platform expansion beyond COVID-19.
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FAQ
What changed in Japan’s approval for Arexvy?
Japan expanded Arexvy eligibility to adults aged 18–49 years who are at increased risk for RSV disease. The label also explicitly includes immunocompromised patients as an at-risk population. [1]
What stage is the Korean hantavirus mRNA vaccine program in?
The Korea University program completed animal efficacy studies and is continuing preclinical work, including toxicity testing. Phase 1 entry is targeted for 2028, pending approvals and funding. [2]
What stood out in Pfizer’s 25vPnC Phase 2 data?
Pfizer reported stronger immune responses against pneumococcal serotype 3 versus PREVNAR 20 after infant doses 3 and 4. The company has already started Phase 3 pediatric studies. [3]
Why did WHO recommend LP.8.1 for COVID-19 vaccines?
WHO TAG-CO-VAC concluded that LP.8.1 generated broadly cross-reactive immune responses against circulating JN.1-descendant variants. The group noted lower responses against BA.3.2. [4]
What is HDT-321 targeting?
HDT-321 is an investigational vaccine candidate for Crimean-Congo hemorrhagic fever (CCHF). The program has entered Phase 1 clinical testing after preclinical development supported by biodefense collaborations. [5]
What is happening with Moderna’s flu vaccine review?
FDA plans to convene its Vaccines and Related Biological Products Advisory Committee on 18 Jun 2026 to review Moderna’s seasonal mRNA influenza vaccine application. [6]
Entities / Keywords
GSK Arexvy RSV approval (Japan): GSK, Arexvy, RSVPreF3, RSV, Japan MHLW, PMDA, immunocompromised, COPD, asthma,
Pfizer pneumococcal vaccine: Pfizer, PF-07872412, 25vPnC, PREVNAR 20, pneumococcal conjugate vaccine, serotype 3, IPD,
WHO COVID-19 antigen guidance: WHO, TAG-CO-VAC, SARS-CoV-2, LP.8.1, XFG, NB.1.8.1, BA.3.2, JN.1, vaccine effectiveness
Moderna flu vaccine review: Moderna, FDA, mRNA influenza vaccine, VRBPAC, regulatory review
Hantavirus programs: Korea University, Hantavirus, Andes virus, Hantaan virus, Seoul virus, mRNA vaccine, DNA vaccine, USAMRIID, HFRS, HPS
HDT Bio CCHF vaccine: HDT Bio, UTMB, HDT-321, CCHF, MCDC, NIH/NIAID, LION platform,
References