COVID-19 booster strategies provide lasting immunity

Murdoch Childrens Research Institute

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Smaller doses of COVID-19 booster vaccines can provide long-lasting immunity, helping to reduce costs and improve access to vaccination, according to new research. And the findings could also inform vaccine dosing and options during future pandemics.

An international research program led by Murdoch Children’s Research Institute (MCRI) and involving more than 2,000 participants across Australia, Indonesia and Mongolia has provided new evidence that will help shape future COVID-19 booster strategies. 

The $17.6 million program, funded by the Coalition for Epidemic Preparedness Innovations (CEPI), evaluated different COVID-19 booster approaches through three randomised clinical trials, tracking participants for up to two years. 

The trials found fractional doses, where people receive half the standard vaccine amount given as boosters, produced strong immune responses that remained comparable to full-dose boosters.

MCRI Dr Nadia Mazarakis said fractional dosing could help extend vaccine supplies, widen coverage and improve equity in future vaccination programs, particularly in low-income countries. 

“This research provides valuable evidence showing that smaller vaccine doses can still provide strong, long-lasting immunity, which is encouraging for countries looking for practical and affordable ways to deliver booster programs,” she said. 

“Fractional dosing attracted global interest during the COVID-19 pandemic when vaccine supplies were limited. While circumstances have changed, the findings remain relevant because they show there may be opportunities to use vaccines more efficiently without compromising immune responses.

“Importantly, these vaccine strategies will reduce costs, extend supplies and support broader and more equitable access to booster programs, especially in resource constrained countries across Southeast Asia and Africa.” 

CEPI Clinical Development Science Lead Amol Chaudari said, “These pivotal insights - produced across different countries, with different vaccines and people who had received different first COVID vaccine doses - essentially show that public health officials can get ‘more bang for their buck’ with COVID vaccine boosters. If COVID cases were to ramp up again and there be strain on the vaccine supply, these findings could be key to expanding vaccination coverage quickly and preventing future infections and deaths. The findings could also prove helpful for future vaccines against other coronaviruses manufactured using similar technologies.”

Results from the Indonesian study, published in Nature Communications, followed more than 1,200 adults for up to two years after receiving either fractional or standard doses of Pfizer or AstraZeneca vaccines, or a standard CoronaVac vaccine.

The researchers found that while fractional doses produced slightly lower immune responses shortly after vaccination, those differences narrowed over time and remained comparable to full doses at 24 months.  

A companion study of 601 Mongolian adults, published in Frontiers in Immunology, discovered a fractional Pfizer booster produced long-lasting antibody responses similar to a full dose for two years. A further analysis of the same cohort reported that key cellular immune responses, which help protect against serious infections, also remained strong.

In Australia, researchers compared mRNA and protein-based booster vaccines as a fourth full dose. Published in the Journal of Infection, the study involving 496 healthy adults found mRNA vaccines generated higher antibody responses. Both vaccine types reduced infections and produced comparable immune responses over 12 months. The study recently received a further $2 million from the National Health and Medical Research Council (NHMRC) to follow the cohort for 30 months to examine the effects of repeated mRNA COVID-19 vaccination.

Additional research from the team published in Vaccine, found vaccination in the morning, rather than afternoon, improved responses to the mRNA vaccine, but not the protein-based vaccine. The findings suggest simple changes to vaccination timing may offer meaningful benefits.

MCRI Associate Professor Paul Licciardi said while the acute phase of the pandemic had passed, COVID-19 remained a significant cause of respiratory illness and death globally. 

“Understanding how long vaccine-induced immunity lasts remains important for future vaccination planning,” he said. “As countries move towards long-term management of COVID-19, we need evidence about which booster strategies provide durable immunity while making the best use of healthcare resources.

“This knowledge can also help future public health strategies to combat emerging pathogens like hantavirus, Ebola and mpox.”

Australia spends about 10 per cent of its gross domestic product (GDP) on healthcare, compared with 4.4 per cent in Mongolia and 2.7 per cent in Indonesia, highlighting the importance of identifying vaccination strategies that maximise the impact of available resources. 

MCRI Associate Professor Claire von Mollendorf said, “These trial results demonstrate that shaping effective public health policy requires monitoring long-term immune responses across diverse settings with variable infection rates and different primary vaccine schedules.”

Publication: John D. Hart, Eddy Fadlyana, Nadia Mazarakis, Nina Dwi Putri, Emma Watts, Kerryn A. Moore, Eleanor F. G. Neal, Djatnika Setiabudi, Muhammad Gilang Dwi Putra, Cattram Nguyen, Aqila Sakina Zhafira, Pratama Wicaksana, Robert Sinto, Dwi Oktavia, Rini Fajarani, Agnes Rengga Indrati, Chrysanti Murad, Yovita Hartantri, Hendarsyah Suryadinata, Yulia Sofiatin, Kusnandi Rusmil, Hindra I. Satari, Sri Rezeki. Hadinegoro, Cissy B. Kartasasmita, Julitasari Sundoro, Paul V. Licciardi, Claire von Mollendorf and Edward K. Mulholland. ‘Immunogenicity of fractional and standard dose COVID-19 vaccine boosters among healthy adults in Indonesia: twenty four month follow-up from a randomised controlled trial,’ Nature Communications. DOI: 10.1038/s41467-025-63598-6

Publication: Tsetsegsaikhan Batmunkh, Eleanor FG Neal, Otgonjargal Amraa, Nadia Mazarakis, Bolor Altangerel, Naranbaatar Avaa, Lkhagvagaram Batbayar, Khishigjargal Batsukh, Kathryn Bright, Tsogjargal Burentogtokh, Lien Anh Ha Do, Gantuya Dorj, John D Hart, Otgonbold Jamiyandorj, Khulan Javkhlantugs, Sarantsetseg Jigjidsuren, Frances Justice, Shuo Li, Khaliunaa Mashbaatar, Kerryn A Moore, Narantuya Namjil, Cattram D Nguyen, Batbayar Ochirbat, Unursaikhan Surenjav, Helen Thomson, Bilegtsaikhan Tsolmon, Paul V Licciardi, Claire von Mollendorf and Kim Mulholland. ‘Fractional BNT162b2 boosters induce durable immune responses after non-mRNA priming in Mongolia: a randomised controlled trial,’ Frontiers in Immunology. DOI: 10.3389/fimmu.2026.1789248

Publication: Nadia Mazarakis, Zheng Quan Toh, Eleanor Neal, Cattram Nguyen, Kathryn Bright, Skky Luu, Leanne Quah, Yan Yung Ng, John Hart, Lien Anh Ha Do, Anna Rudel, Shashini Dassanayake, Rachel A. Higgins, Rachael Carissa, Darren Suryawijaya Ong, Frances Justice, Kerryn A. Moore, Emma Watts, Kanta Subbarao, Kim Mulholland, Claire von Mollendorf and Paul V. Licciardi. ‘Immunogenicity and efficacy over 12 months following a fourth dose of a bivalent mRNA or protein-based COVID-19 vaccine: A randomised controlled trial in Australia,’ Journal of Infection. DOI: 10.1016/j.jinf.2026.106727 

Available for interview:

Associate Professor Paul Licciardi, MCRI Group Leader, Vaccine Immunology

Associate Professor Claire von Mollendorf, MCRI Team Leader, New Vaccines

Dr Nadia Mazarakis, MCRI Postdoctoral Researcher, Vaccine Immunology

 

 

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Journal

Journal of Infection

DOI

10.1016/j.jinf.2026.106727 

Method of Research

Randomized controlled/clinical trial

Subject of Research

People

Article Title

Immunogenicity and efficacy over 12 months following a fourth dose of a bivalent mRNA or protein-based COVID-19 vaccine: A randomised controlled trial in Australia.

 

Public investment in liver transplants saves lives and is also beneficial in economic and social terms

Pompeu Fabra University (UPF), the National Transplant Organization (ONT) and Vall d’Hebron University Hospital have led the first study to assess the economic feasibility of the Spanish transplant system, in addition to its impact on patients’ health

Universitat Pompeu Fabra - Barcelona

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Public investment in liver transplants not only saves lives and substantially improves patients’ survival and quality of life, but also generates a positive long-term social and economic return. So demonstrates a pioneering study led by researchers from Pompeu Fabra University (UPF), the National Transplant Organization (ONT), and Vall d’Hebron University Hospital. More than four decades after the first liver transplant in Spain in 1984, this is the first study to perform a global assessment of the impact of these interventions, not only from the perspective of patients’ health, but also from the economic and social perspectives.

The study reveals that liver transplant patients currently contribute at least 100 million euros per year to the Spanish economy. This figure exceeds the annual investment in liver transplants, which stands at around 75 million euros. If the costs of post-surgical treatment -lifelong immunosuppressive therapy to prevent the rejection of the transplanted organ- are also taken into account, this investment would total 90 million euros per year. The research is based on official and historical data from the Spanish Registry of Liver Transplantation (RETH), the ONT, and the Spanish Society of Liver Transplantation (SETH), which include transplants conducted between 1984 and 2024.

The system has been profitable since the start of the 21st century

When liver transplants began in the mid-1980s, only a few dozen were carried out each year, while currently the figure stands at about 1,200. Precisely when this figure began to stabilize, in the early 2010s, the costs of the operation and patient treatment and the economic return to society cancelled each other out, and today the balance is clearly positive. This is possible thanks to the economic contributions of patients of working age (active population), although it must not be forgotten that transplanted children will end up doing the same in the longer term and that older people, given the foreseen increase in life expectancy and quality, will be able to make increasing contributions to society beyond the labour market.

Longer life expectancy for patients, especially children

The research also reveals an increase in transplant patients’ life expectancy and quality. While in the 1980s, patients gained an average of 10 years of life, today this figure ranges between 16 and 20 among adults and between 21 and 29 in the case of children, due to significant advances in paediatric surgery. Currently, the Spanish liver transplant system is an international benchmark and the state organ donation rate is one of the highest in the world (52.6 per million inhabitants).

The results of the study have been published in an article in Health Economics Review. At UPF, the principal investigator is Gemma Piella, co-director of the SIMBYOsys group of the BCN MedTech Unit of the Department of Engineering, who led the study together with Gloria de la Rosa (National Transplant Organization), and Concepción Gómez Gavara (linked to Vall d’Hebron University Hospital while the study was being conducted and now, to Hospital Clínic de Barcelona). Other co-authors are Edson Plasencia (article lead author, with the UPF SIMBYOsys group), Gloria Merino Pinto (Centre for Research in Economics and Health -CRES- of the UPF Department of Economics and Business), Roger Sabater Mezquita (CRES-UPF and the Department of Econometrics, Statistics and Applied Economics at the University of Barcelona), Itxarone Bilbao (Vall d’Hebron University Hospital and Department of Surgery at the UAB), and Gerardo Blanco-Fernández (SETH and University Hospital of Badajoz).

Roger Sabater (UPF and UB) and Edson Plasencia (UPF) highlight: “Thanks to gradual technological advances, more and more contemporary surviving recipients of working age have accumulated, whose income exceeds the costs of new transplants and immunosuppressive treatments in each of the last fifteen years, and with an increasingly larger margin. This trend will continue into the future if innovative technology is able to further improve survival and reduce the likelihood of re-transplantation”.

Gloria de la Rosa, an assistant physician at the ONT, adds that this study shows the value of keeping robust national records sustained over time: “The Spanish Registry of Liver Transplantation, together with the data from the ONT concerning donations, waiting lists and transplant activity, allow analysing four decades of the evolution of liver transplantation in Spain from the clinical, organizational and social standpoints. This data is essential to evaluate results, guide planning, and continue improving a model based on the quality, equity and solidarity of donors and their families”.

Regarding future challenges, Gemma Piella (UPF) explains that the number of donors is still below the number of patients awaiting transplants. This has led her to develop a new smart system, LiverColor, which will reduce the margin of error of current methods used to identify which donated livers are suitable for transplantation and prevent valid organs from going to waste. Piella highlights “the potential of biomedical technology to further improve the efficiency of the system”.

Dr. Concepción Gómez Gavara adds: “Innovation in the field of transplantation has traditionally been a particularly complex challenge, as any new technology must demonstrate with the utmost rigor that it can improve current outcomes without compromising patient safety or graft survival. With this vision, we launched a line of work that combines clinical and surgical expertise with technological knowledge and engineering, leading to the development of LiverColor, a more precise, objective, and personalized transplantation model.” Currently, at Hospital Clínic Barcelona, Gómez Gavara continues to drive the development and evolution of the technology, exploring new applications and innovation opportunities to further improve the transplantation process.

Reference article:

Plasencia Sánchez, E., Gómez Gavara, C., Merino Pinto, G. et al. The Spanish transplantation model as a benchmark: clinical, societal, and economic impact of liver transplants in Spain (1984–2024). Health Econ Rev (2026). https://doi.org/10.1186/s13561-026-00801-4

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Journal

Health Economics Review

DOI

10.1186/s13561-026-00801-4 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

The Spanish transplantation model as a benchmark: clinical, societal, and economic impact of liver transplants in Spain (1984–2024)

 

Study: Golf generates nearly €630 million in societal benefits in Finland

PUBLIC VS TRUMP GOLF COURSES

University of Eastern Finland

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A new study published in Frontiers in Sports and Active Living shows that Finnish golf players spend approximately €330 million on golf annually, and that this generates an estimated benefit to society almost twice as high.

The study analysed the societal significance of golf in Finland in 2021. It examined two dimensions: the flow of money spent by golf players into different sectors of the economy, and the broader societal impacts of the physical activity and well-being promoted by golf, including their effects on healthcare costs.

SROI, or Social Return on Investment, is a method used to assess the social return of investments, that is, their societal impacts, value and benefits in relation to their costs. The SROI ratio estimates the return on an investment relative to the amount invested. In this study, the SROI of golf illustrates the sport’s impacts on public health and the national economy. The SROI ratio was 1.9, rising to as much as 2.4 when economic multiplier effects were taken into account.

The main data for the study were collected through an online survey in May 2021, completed by 1,052 members of the Finnish Golf Union. The study also drew on existing research literature, financial statements from ten golf courses and other national economic statistics.

The first author of the study was Julia Kettinen, a visiting researcher at the University of Eastern Finland and a postdoctoral researcher at ETH Zürich. The research team included researchers from Finland, Switzerland and the United Kingdom.

 

Golf players’ spending flows widely into the national economy

Golf players spent a total of approximately €330 million per year on their sport. The largest single category of expenditure comprised shareholder, club membership and green fees, together with other costs related to playing, amounting to approximately €150 million. The second-largest expenditure category was the purchase of golf equipment in Finland, at approximately €59 million, followed by domestic golf tourism, at €50 million. This spending supported the national economy through wages (€57 million), local suppliers and subcontractors (€50 million), and domestic tourism services (€50 million), among other channels.

 

Golf promotes physical activity and generates €80 million in savings for society

Golf players were considerably more physically active than Finns on average: of the survey respondents, 89% engaged in physical activity for at least four hours per week throughout the year and 59% engaged in vigorous physical activity for more than two hours per week. Owing to these higher levels of physical activity, golf participation was estimated to generate annual societal savings and additional revenues of approximately €80.9 million. The largest individual benefit categories were increased tax revenues (€46.0 million), reduced costs of institutional care for older people (€11.0 million) and lower disability pension costs (€8.1 million).

 

SROI ratio of 1.9 – golf creates positive externalities

The SROI analysis consisted of three components: the enjoyment and well-being experienced by players (€330 million), economic flows in Finland (€220 million), and societal savings and added revenues (€80 million). Total benefits were estimated at approximately €630 million, resulting in an SROI ratio of 1.9. When the economic multiplier effects of sports and recreation services are taken into account, the economic impact rises to approximately €370 million, total benefits to approximately €770 million and the SROI ratio to 2.4. The result is in line with other SROI studies in the sport and physical activity sector, in which SROI ratios have ranged from 1.92 to 3.28.

The findings suggest that golf players do not personally receive all the societal value generated by their participation in the sport: they spend €330 million to gain personal benefits, while at the same time generating approximately €300 million in additional benefits for wider society.

“The results show that golf is more than just a leisure activity – it can be a significant societal investment. The sport brings economic activity to Finland and keeps golf players more physically active than Finns on average. It is a particularly valuable form of physical activity for middle-aged and older adults, among whom physical activity has the greatest potential to reduce healthcare costs,” says Julia Kettinen.

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Journal

Frontiers in Sports and Active Living

DOI

10.3389/fspor.2026.1832817 

Article Title

The social significance of golf in Finland in the year 2021 based on SROI analysis

 

Brexit nurse exodus linked to more than 3,700 extra hospital deaths, researchers warn

University of Surrey

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The sharp fall in EU nurses joining the NHS after the Brexit referendum may have contributed to more than 1,200 additional patient deaths each year in England, according to new research led by the University of Surrey in partnership with the University of Aberdeen, Harvard Business School and Vienna University of Economics and Business (WU). 

The research suggests the biggest impact was felt by hospitals that had relied most heavily on recruiting nurses from the EU before the 2016 vote. While these hospitals largely replaced departing EU staff with nurses from outside Europe, patient care still worsened, with higher rates of emergency deaths and unplanned readmissions. 

The study, published in The Economic Journal, the official journal of the Royal Economic Society, estimates that, across the first three years after the referendum, hospitals with greater dependence on EU nurses experienced 3,714 additional emergency patient deaths and almost 14,000 extra emergency readmissions to hospital after initial discharge. The researchers found no evidence that these patient health outcomes were caused by reduced hospital funding, fewer beds or an increase in patient numbers. 

Researchers say the findings challenge the idea that simply filling vacancies is enough to protect healthcare quality. Instead, they argue that sudden restrictions on international recruitment can force employers to lower hiring standards when skilled workers become harder to attract. 

To investigate the impact, researchers analysed more than 32 million emergency hospital admissions across 130 NHS hospitals between 2012 and 2019. They linked patient records with NHS workforce data to compare hospitals according to how reliant they had been on EU nurses before the referendum. They found that hospitals with the highest proportions of EU nurses before Brexit experienced the greatest decline in patient outcomes afterwards.  

Giuseppe Moscelli, Professor of Economics at the University of Surrey and principal investigator of the study, said: 

“Hospitals were able to recruit replacement nurses, but our findings suggest they had to recruit from a smaller and less experienced pool of applicants. That appears to have had real consequences for patients.” 

The researchers found hospitals responded to the drop in EU applicants by recruiting more nurses from outside Europe. However, newly recruited nurses after the referendum were more likely to be appointed to lower NHS salary bands, suggesting they had less experience or fewer qualifications than those they replaced. The research also found nurses working in the most affected hospitals reported being less satisfied with the quality of care they were able to provide.  

Professor Moscelli continued: 

“Many countries, including the UK, depend on internationally trained healthcare professionals. Our findings show that immigration policy can have unintended consequences far beyond the labour market. Decisions that make a country less attractive to skilled workers can ultimately affect the quality of care received by patients. 

“Policymakers should recognise that healthcare systems competing for skilled international workers need to consider not only the number of staff they recruit, but also how immigration policies influence who chooses to apply.”  

ENDS 

Notes to editors 

• For interviews with Professor Giuseppe Moscelli, please contact: mediarelations@surrey.ac.uk 

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Journal

The Economic Journal

DOI

10.1093/ej/ueag088 

Article Title

Immigration, Workforce Composition, and Organisational Performance: The Effect of Brexit on NHS Hospital Quality

Article Publication Date

18-Jul-2026

 

When Black Sea waters reshaped Eastern Mediterranean circulation 11,000 years ago

A new study led by the University of Barcelona reveals that freshwater exported from the Black Sea to the Aegean Sea triggered major environmental changes across the Eastern Mediterranean

University of Barcelona

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A new study led by the University of Barcelona reveals that freshwater exported from the Black Sea to the Aegean Sea triggered major environmental changes across the Eastern Mediterranean.

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Credit: Communications Earth & Environment

An international team of researchers led by the University of Barcelona, in collaboration with the University of the Aegean and the Hellenic Centre for Marine Research, has uncovered evidence showing that a massive outflow of low-salinity water from the Black Sea into the Aegean Sea during the Early Holocene (approximately 11,000-6,000 years ago) played a much more important role in shaping the Eastern Mediterranean than previously thought.

The study, published in the Nature Portfolio journal Communications Earth & Environment, demonstrates that freshwater exported from the Black Sea enhanced surface-water stratification in the Aegean Sea, suppressing the formation of deep waters and contributing to the development of the so-called Sapropel 1, a widespread organic-rich sediment layer deposited across the Eastern Mediterranean during the Early Holocene.

The findings extend beyond the Eastern Mediterranean’s past. By demonstrating how large freshwater inputs can disrupt deep-water formation and reorganize marine circulation, the study offers valuable insights into the links between climate, hydrology and ocean circulation during warm periods, helping scientists better understand the potential consequences of future climate change.

The Black Sea: More important than previously thought

For decades, scientists have largely attributed the formation of Sapropel 1 to increased freshwater input from North African rivers and enhanced precipitation over the northern Mediterranean region. These processes were thought to reduce deep-water formation and promote conditions favourable for the accumulation of organic-rich sediments on the seafloor. The new findings challenge this long-standing view by identifying the Black Sea as a major and previously underestimated driver of these environmental changes.

The results reveal that the combination of intensified meltwater input and increased precipitation across the vast Black Sea drainage basin during the Early Holocene strengthened the export of low-salinity water through the Dardanelles Strait. This freshwater pulse triggered a major reorganization of water masses in the northern and central Aegean Sea, increasing stratification of the water column and reducing the formation of deep waters.

“Our findings show that the formation of Sapropel 1 cannot be explained solely by changes in North African river discharge and regional precipitation,” explains Dimitris Evangelinos, lead author of the study and member of the Marine Geosciences Research Group (Gmar) at the UB’s Faculty of Earth Sciences.

“The Black Sea acted as a powerful source of freshwater that fundamentally altered ocean circulation in the Aegean Sea and played a decisive role in the environmental transformation of the Eastern Mediterranean”, explains Evangelinos, from the UB’s Department of Earth and Ocean Dynamics.

More than 42,000 years of environmental history

​​​To reach these conclusions, the researchers analysed a marine sediment core recovered from the central Aegean Sea, close to key deep-water formation areas in the northern Aegean. The sediment archive preserves more than 42,000 years of environmental history. The study relied on a suite of advanced analyses carried out in state-of-the-art laboratories at the UB and its Science and Technology Centres (CCiTUB). By combining multiple innovative approaches, including grain-size analysis, X-ray fluorescence scanning, radiogenic isotopes and stable isotope geochemistry, the team reconstructed past changes in ocean circulation and distinguish the influence of Black Sea outflow from other climatic and hydrological processes.

This research was supported by the MORIA project (2023-2027), and received funding from the the State Research Agency of the Ministry of Science, Innovation and Universities, the European Research Council Consolidator Grant and the NextGenerationEU programme, among other institutions.

 

When Black Sea waters reshaped Eastern Mediterranean circulation 11,000 years ago [AUDIO] 
UB researcher, Dimitris Evangelinos, explains the results of the research.

 

Marine sediment core scanned using an Avaatech X-ray fluorescence (XRF) core scanner at the CORELAB, Universitat de Barcelona (Spain) to obtain high-resolution geochemical records. The dark sedimentary unit visible in the upper part of the core corresponds to the organic-rich sapropel S1 layer, which is characterized by elevated organic matter content relative to the surrounding sediments.

 

Some of the study's authors aboard the Spanish research vessel (R/V) Odón de Buen. From left to right: Isabel Cacho, Leopoldo Pena, Sara Campderrós, Dimitris Evangelinos, and Jaime Frigola.

 

Dimitris Evangelinos, first author of the study and postdoctoral researcher at the Universitat de Barcelona, analyzing marine sediment samples used to reconstruct past Mediterranean ocean and climate changes.

 

Sara Campderrós, author of the study, sampling the marine sediment core for sedimentological, geochemical, and isotopic analyses

Credit

UNIVERSITY OF BARCELONA

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Journal

Communications Earth & Environment

DOI

10.1038/s43247-026-03730-6 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Early Holocene vigorous Black Sea outflow and the onset of sluggish Aegean deep-water convection