EMBARGOED UNTIL 7:00 PM GMT / 2:00 PM EST THURSDAY, NOVEMBER 7, 2024

• Enhanced genomic surveillance capabilities have provided new insights into global viral evolution;
• Seasonal flu showed a “remarkable” return to pre-pandemic levels once international air travel resumed;
• Regions with fewer COVID-19 restrictions have been associated with sustained influenza virus transmission.

Seasonal influenza epidemics impose substantial burdens on healthcare systems and cause more than 5 million hospitalizations in adults each year. The current approach to influenza vaccine development requires comprehensive surveillance of circulating strains, which are constantly moving from continent to continent. The reduction in global human mobility during the COVID-19 pandemic has provided a unique opportunity to assess how seasonal influenza is affected during pandemics.

In this new study, an international team of researchers, including from the University of Oxford, Fudan University and KU Leuven, combined data on the spread of seasonal flu, its genetic structure and international travel patterns to study how they moved seasonal flu viruses. evolved. This approach helped estimate how long viruses remained in certain regions during periods of high and low volumes of international travel and how their genetic diversity changed before, during and after the COVID-19 pandemic.

During the COVID-19 pandemic, levels of seasonal influenza have declined worldwide due to the COVID-19 pandemic-related restrictions on movement and population mixing. However, the subsequent rapid rebound of influenza, once air travel returned to pre-pandemic levels, showed that the virus was in most cases maintained during the pandemic with continued viral movements and accumulation of genetic diversity.

Lead study author Zhiyuan Chen (University of Oxford and Fudan University) says: “It was remarkable how quickly seasonal influenza returned to a pre-pandemic equilibrium just a few years after the peak of the COVID-19 pandemic.”

Tropical climates, such as those found in South and East Asia, allow for continuous transmission of influenza throughout the year, thereby creating a wider range of influenza strains and increasing overall viral diversity. The increased capacity for genomic surveillance of the virus during the COVID-19 pandemic has provided more details about the role of other regions, such as Africa and West Asia, in the global circulation of influenza. These regions also showed evidence of sustained transmission and had relatively fewer travel restrictions during the pandemic, in part due to lower levels of COVID-19 transmission.

CO-AUTHOR Professor Moritz Kraemer (Department of Biology and Institute of Pandemic Sciences, University of Oxford) says: “The increased capacity for genomic surveillance established during the COVID-19 pandemic means that we are finally gaining deeper insight into the global distribution patterns of seasonal influenza and other respiratory viruses. These new and large, openly accessible data sets provide an opportunity to learn about the complicated relationships of climate, co-circulating viruses and human behavior.”

In addition, with this increased global virus surveillance capacity, better monitoring of seasonal influenza may be possible to reduce the risk of vaccine mismatches, help inform more effective interventions, and reduce the burden of seasonal influenza on our health systems. This is especially relevant as more regions become suitable for year-round influenza circulation with changes in climatic conditions.

Co-author Professor Hongjie Yu of Fudan University says: “Additional efforts should continue to focus on continuous surveillance of seasonal influenza viruses and other respiratory pathogens, especially in regions with limited resources. Surveillance systems established for seasonal respiratory pathogens could also play an extremely vital role when the next pandemic occurs in the future.”

Notes for editors

The paper “Pandemic COVID-19 interventions reshaped the global spread of seasonal influenza viruses” will be published in the journal Science TO https://doi.org/10.1126/science.adq3003. Advance copies of the paper may be obtained from Science press pack, SciPak, la or by contacting [email protected].

Corresponding author interviews are available upon request.

Media contact: Professor Moritz Kraemer: [email protected]

About the University of Oxford

The University of Oxford has been ranked 1st in the Times Higher Education World University Rankings for the ninth consecutive year and 3rd in the QS World Rankings 2024. At the heart of this success are the two pillars of our ground-breaking research and innovation and our distinctive educational offer .

Oxford is world renowned for excellence in research and teaching and is home to some of the most talented people across the globe. Our work helps the lives of millions of people by solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research, together with our personalized approach to teaching, generates imaginative and inventive insights and solutions.

Through its research commercialization arm, Oxford University Innovation, Oxford is the UK’s largest applicant for university patents and ranks first in the UK for university spinouts, having created over 300 new companies since 1988. More than a third of these companies have been created. in the last five years. The University is a catalyst for prosperity in Oxfordshire and the UK, contributing £15.7 billion for the UK economy in 2018/19 and supports over 28,000 full-time jobs.

The Department of Biology is a department of the University of Oxford within the Division of Mathematics, Physics and Life Sciences. It uses academic strength across a range of bioscience disciplines to address global challenges such as food security, biodiversity loss, climate change and global pandemics. It also helps train and equip the biologists of the future through holistic undergraduate and postgraduate courses. For more information visit www.biology.ox.ac.uk.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of press releases posted on EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.