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Ed Hill
@edmhill.bsky.social
Researcher in mathematical epidemiology & modelling of infectious disease dynamics. #academicsky Affiliation: Civic Health Innovation Labs (CHIL) & the Institute of Population Health, University of Liverpool. Personal webpage: edmhill.github.io
493 followers342 following378 posts
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EHedmhill.bsky.social

5/ Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 💉 WHO recommends trivalent vaccines for use in 2025 southern hemisphere influenza season 🧪 Contains a H1N1pdm09-like virus, a H3N2-like virus & a B/Victoria lineage-like virus /end

For trivalent vaccines for use in the 2025 southern hemisphere influenza season, the WHO recommends the following: Egg-based vaccines • an A/Victoria/4897/2022 (H1N1)pdm09-like virus; • an A/Croatia/10136RV/2023 (H3N2)-like virus; and • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus. Cell culture-, recombinant protein- or nucleic acid-based vaccines • an A/Wisconsin/67/2022 (H1N1)pdm09-like virus; • an A/District of Columbia/27/2023 (H3N2)-like virus; and • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.
The recommendation for the B/Yamagata lineage component of quadrivalent influenza vaccines remains unchanged from previous recommendations: • a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus. The continued absence of confirmed detection of naturally occurring B/Yamagata lineage viruses after March 2020 is indicative of a very low risk of infection by B/Yamagata lineage viruses. Consistent with previous recommendations, it remains the opinion of the WHO influenza vaccine composition advisory committee that inclusion of a B/Yamagata lineage antigen in quadrivalent influenza vaccines is no longer warranted, and every effort should be made to exclude this component as soon as possible.
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EHedmhill.bsky.social

4/ Technical briefing content 🌍 Summary of seasonal influenza activity in different global transmission zones 🔬 Genetic and antigenic characteristics of recent seasonal influenza viruses, human serology & antiviral susceptibility 💉 The recommendation for composition of influenza virus vaccines

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EHedmhill.bsky.social

3/ How are influenza virus vaccine recommendations made? 📊 Uses data from WHO Global Influenza Surveillance & Response System (GISRS) Data types mentioned in FAQ doc include: ▶️ Surveillance data ▶️ Antigenic & genetic characterisation of viruses ▶️ Human serology studies ▶️ Vaccine effectiveness

3. How are influenza virus vaccine recommendations made? Data and information from the GISRS network, which includes NICs, WHO CCs, WHO ERLs and WHO H5 Reference Laboratories, and from other sources are used to make vaccine virus recommendations. This includes: • Surveillance data: Virus surveillance data from the GISRS network, complemented with epidemiologic and clinical findings, inform the vaccine virus selection process. • Antigenic characterization of viruses: GISRS laboratories, in particular WHO CCs, use post-infection ferret antisera and pooled post-vaccination human sera to evaluate antibody reactivity with the surface proteins (antigens) of circulating and vaccine influenza viruses. Antigenic cartography is used to visualize relatedness of viruses based on the data provided by WHO CCs. • Human serology studies with influenza virus vaccines: WHO CCs and WHO ERLs test how well antibodies from vaccinated people react with recently circulating influenza viruses.
• Virus fitness forecasting: Virus fitness relates to the likelihood of any emerging groups of viruses becoming more prevalent in coming months. Information from modelling studies, based on genetic sequences available in databases and antigenic information provided by the WHO CCs is considered. • Antiviral susceptibility: GISRS laboratories analyse influenza viruses to determine if they remain susceptible to the antiviral drugs approved for treatment of influenza infections. This information is taken into consideration when specific viruses are selected as candidate vaccine viruses (CVVs).
• Vaccine effectiveness: The Global Influenza Vaccine Effectiveness (GIVE) Collaboration, made up of many different studies conducted in countries in both the northern and southern hemispheres, provides information on vaccine performance in previous influenza seasons and interim reports on the current season. • Availability of candidate vaccine viruses (CVVs): CVVs are essential for production of vaccines in a timely manner for the next influenza season. Most vaccines produced globally use egg-based manufacturing processes which require CVVs that replicate well in eggs while cell-based vaccines require CVVs that replicate well in cell culture. Separate recommendations are made for egg- and cell-based
CVVs because of the differing replication and manufacturing processes. Influenza virus vaccines comprised of recombinant protein influenza virus antigens do not require CVVs for manufacturing. These data, and other findings made available by GISRS, are evaluated during WHO Consultations usually held in February and September of each year. The consultations include experts from WHO CCs, WHO ERLs, WHO H5 Reference Laboratories, NICs, OFFLU, academic institutions, and other national and regional institutions.
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EHedmhill.bsky.social

2/ Purpose of WHO recommendations on influenza virus vaccine composition? ▶️ Periodic update of influenza vaccines is necessary due to constant evolving nature of influenza viruses 🗓️ WHO holds technical consultations twice annually (Feb & Sep), once for southern & once for northern hemispheres

2. What is the purpose of WHO recommendations on the composition of influenza virus vaccines? These WHO recommendations provide a guide to national public health and regulatory authorities, and vaccine manufacturers for the development and production of influenza virus vaccines for the next influenza season and for pandemic preparedness. In contrast to many other vaccines, the viruses in seasonal influenza vaccines need to be evaluated and updated regularly because circulating influenza viruses evolve continuously and may not be optimally covered by the current vaccines. Recommendations are usually made in February for the following influenza season in the northern hemisphere and in September for the following influenza season in the southern hemisphere. The recommendation dates are chosen to provide approximately 6-8 months for the production, regulatory approval and distribution of the manufactured vaccines.
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EHedmhill.bsky.social

1/ How does WHO make seasonal influenza vaccine composition recommendations❓ 🧪 Recommendations announced (on 27 Sep 2024) for 2025 southern hemisphere influenza season 🔗 News release: www.who.int/news/item/27...www.who.int/publications...cdn.who.int/media/docs/d...

Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season
Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season

Publications of the World Health Organization

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EHedmhill.bsky.social

Informative discussion - see both post and replies on what possible cluster of human bird-flu infections in Missouri says about H5N1 avian influenza transmission potential. 🧪 #EpiSky

AKadamjkucharski.bsky.social

What might below say about transmission potential? If (still a big if) this is a transmission cluster, then we now have 14 reported spillover cases (i.e. single human cases unrelated to others) and one possible cluster of 9 (i.e. unknown source case + patient + 7 suspected onwards cases)....

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Reposted by Ed Hill
THtah-sci.bsky.social

This is bad from a surveillance point of view. In the event that there were several human infections with a new H5N1 flu in the same cluster that would tip it so a wider outbreak was more likely than not in my estimation. But we don't know because it wasn't tested for.

HBhelenbranswell.bsky.social

More from Missouri: #CDC reports that Missouri has found 4 more health workers who developed mild illness after caring for the confirmed #H5N1 #birdflu case hospitalized in August. None were tested while ill. www.statnews.com/2024/09/27/b...

Four more health care workers reported illnesses after caring for bird flu case in Missouri
Four more health care workers reported illnesses after caring for bird flu case in Missouri

The CDC said an investigation into a human H5N1 bird flu infection in Missouri has found four additional health care workers who fell ill after caring for the patient.

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EHedmhill.bsky.social

📄 UKHSA data: Seasonal #influenza#EpiSky#fluassets.publishing.service.gov.uk/media/66f525...assets.publishing.service.gov.uk/media/66f535...

Influenza Through Respiratory DataMart, influenza positivity remained stable at 1.6% in week 38 compared with 1.4% in the previous week.
Laboratory surveillance Respiratory DataMart system (England) In week 38 2024, data is based on reporting from 11 out of the 16 sentinel laboratories. In week 38 2024, 3,896 respiratory specimens reported through the Respiratory DataMart System were tested for influenza. There were 63 positive samples for influenza; 28 influenza A(not subtyped), 22 influenza A(H3N2), 1 influenza A(H1N1)pdm09, and 12 influenza B. Overall, influenza positivity remained stable at 1.6% in week 38 compared with 1.4% in the previous week.
Figure of Respiratory DataMart weekly positivity (%) for influenza, SARS-CoV-2, RSV and rhinovirus in England. Covers week 39 2023 (approx September 2023) to week 38 2024 (ending 22 September 2024).
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EHedmhill.bsky.social

4/ Research gaps ❓ Should the West vaccinate poultry for H5N1? ❓ Can H5N1 be eliminated in US dairy cattle? ❓ Prospects for the Future - severity of a future H5N1 pandemic remains unclear /end

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EHedmhill.bsky.social

3/ How could H5N1 become a pandemic? ▶️ Examines how changes in the ecology & molecular evolution of H5N1 in wild & domestic birds increases opportunities for spillover to mammals. ▶️ Discusses the chance of different evolutionary pathways that could turn H5N1 into a pandemic virus

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EH
Ed Hill
@edmhill.bsky.social
Researcher in mathematical epidemiology & modelling of infectious disease dynamics. #academicsky Affiliation: Civic Health Innovation Labs (CHIL) & the Institute of Population Health, University of Liverpool. Personal webpage: edmhill.github.io
493 followers342 following378 posts
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