ESWI annual report 2022

Annual Report 2022

ESWI Members

European Scientific Working group on Influenza and other Respiratory Viruses (ESWI) is a group of key scientific experts in influenza who have joined forces to reduce the burden of Respiratory Virus Infections in Europe.

EXECUTIVE MEMBERS

■ Ab Osterhaus, Chairman, Research Center for Emerging Infections and Zoonoses Hannover, Germany

■ Colin Russell, Vice-President, University of Amsterdam, The Netherlands

■ Ted van Essen, Treasurer, Amersfoort, The Netherlands

BOARD OF DIRECTORS

■ Gülsah Gabriel, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany

■ Marco Goeijenbier, Spaarne Gasthuis, Amsterdam, The Netherlands

■ Edward C. Hutchinson, University of Glasgow, UK

■ George Kassianos, GP and National Immunisation Lead Royal College of General Practitioners, UK

■ Florian Krammer, Icahn School of Medicine at Mount Sinai, New York, United States of America

■ Stefania Maggi, Neuroscience Institute, Padova, Italy

■ Peter Openshaw, Imperial College London, UK

■ Roman Prymula, Military Hospital of Hradec Kralove, Czech Republic

■ Paula Tähtinen, Turku University Hospital, Finland

ASSOCIATE MEMBERS

■ Claude Hannoun, former Institut Pasteur, Paris, France

■ Susanne Herold, University of Giessen Lung Centre, Germany

■ Ursula Kunze, University of Vienna, Austria

■ Bram Palache, Influenza Expert, IFPMA, The Netherlands

■ Sylvie van der Werf, Institut Pasteur, Paris, France

A full list of ESWI’s members with biographies is available at https://eswi.org/site/eswi/members

New members in 2022

Prof. Krammer is the Principal Investigator of the Sinai-Emory Multi-Institutional Collaborative Influenza Vaccine Innovation Center (SEM-CIVIC). It aims to develop improved seasonal and universal influenza virus vaccines that induce long lasting protection against drifted seasonal, zoonotic and future pandemic influenza viruses. The Krammer laboratory focuses on understanding broadly-reactive immune responses against the surface glycoproteins of RNA viruses such as influenza with the goal to develop better vaccines and novel therapeutics.

Dr. Maggi has a specific interest in the epidemiology of ageing and in the analysis of factors promoting health ageing in a lifelong approach. As Research Director Ageing branch at the Institute of Neuroscience, Consiglio Nazionale Delle Ricerche (CNR), she coordinates several national and international research projects on nutrition, vaccines and lifestyle as key factors for promoting healthy ageing.

Dr. Tähtinen works as a paediatrician at Turku University Hospital. Her research focuses on respiratory tract infections, especially acute otitis media. Currently, she is setting up her own research group with the main focus on prevention and treatment of respiratory tract infections. Paula Tähtinen is also an Adjunct Professor and Clinical Lecturer at the University of Turku, Finland.

ESWI extends a special thanks to Terho Heikkinen, Sylvie van der Werf and Susanne Herold, for 18 years, 22 years and 6 years of board membership in ESWI, respectively.

Terho Heikkinen, who formally left ESWI in 2022, has been actively involved in international research collaboration in the field of respiratory infections, especially those caused by influenza or respiratory syncytial viruses. Sylvie van der Werf, specialised in

epidemiological and virological surveillance of human influenza viruses and of other respiratory viruses, and Susanne Herold, specialised in pneumonia, influenza viruses and coronaviruses, retired from the Board but remain active Associate Members of ESWI.

ESWI thanks Güelsah Gabriel for her role in the Executive Committee as Vice-Chair. She was succeeded by Colin Russell at the June General Assembly

Florian Krammer

ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI, NEW YORK, UNITED STATES OF AMERICA.

Stefania Maggi

NEUROSCIENCE INSTITUTE, PADOVA, ITALY

Paula Tähtinen

TURKU UNIVERSITY HOSPITAL, FINLAND

ESWI Coalition Partners

Collaboration is at the core of ESWI and together with our coalition partners, we advance the important work to reduce the burden of major acute respiratory virus infections.

■ Age Platform Europe

■ Asia Pacific Alliance for the Control of Influenza (APACI)

■ European Academy of Allergy & Clinical Immunology (EAACI)

■ European Academy of Paediatrics (EAP)

■ European Forum of National Nursing and Midwifery Associations (EFNNMA)

■ European Heart Network (EHN)

■ European Lung Foundation (ELF)

■ European Medical Association (EMA)

■ European Public Health Alliance (EPHA)

■ European Respiratory Society (ERS)

■ European Society of Clinical Microbiology and Infectious Diseases (ESCMID)

■ European Society for Paediatric Infectious Diseases (ESPID)

■ European Union Geriatric Medicine Society (EUGMS)

■ Foundation of European Nurses in Diabetes (FEND)

■ International Diabetes Federation-Europe (IDF-Europe)

■ International Federation on Ageing

■ Immunisation Coalition

■ International Society of Travel Medicine (ISTM)

■ Middle East, Eurasia And Africa Influenza Stakeholders Network (ME’NA-ISN)

■ Pandemic Action Network (PAN)

■ Pharmaceutical Group to the EU (PGEU)

■ Ready2Respond

■ US National Adult and Influenza Vaccine Summit

■ Vaccines Europe

■ World Organization of Family Physicians (WONCA)

New Coalition Partners in 2022

The Pandemic Action Network was launched in April 2020 by leaders in global health advocacy, crisis response, and communications. It is a partnership of over 250 diverse organisations including Johns Hopkins Centre for Communication Programs, Save the Children, UN Foundation, African Union, African CDC, Bill and Melinda Gates Foundation, CDC Foundation, Foundation of American Scientists. The mission is to drive collective action to bring an end to the COVID-19 crisis focusing on pandemic preparedness. Activities include policy, advocacy, communication recommendations, working collaboratively, catalysing action and filling gaps.

Immunisation Coalition is an independent not for profit organisation and the leading voice in whole-of-life immunisation in Australia, protecting citizens against vaccine preventable diseases. It collaborates with organisations such as Primary Health Networks (PHNs), Public Health Units, Government health departments and other groups that fight vaccine hesitancy.

Middle East, Eurasia And Africa Influenza Stakeholders Network (ME’NA-ISN) was established in 2019 as an association of experts representative of a multidisciplinary approach operating across different countries in the Region. The Network’s primary objective is to address the challenge of low levels of vaccine uptake, generating data and providing expertise for the policy makers and health care systems in order for each country in the Region to develop an effective influenza program to reduce the burden of influenza in the Region.

A full list of ESWI’s coalition partners with links to their websites is available here:

https://eswi.org/site/networks/coalition-partners

ESWI Airborne Podcast series

In March, ESWI launched the podcast series ESWI Airborne. Educational and captivating conversations with ESWI members about the world of respiratory viruses. In these episodes, global health experts, from ESWI coalition partners or IDC members, are invited to join the talks.

ESWI Airborne is moderated by Clare Taylor, a known science communicator, writer, editor and policy analyst. Each episode lasts between 20 and 30 minutes and the entire series is disseminated through various podcast platforms, such as Spotify and Apple Podcasts.

2022 Episodes

1. Ab Osterhaus. Pandemic Preparedness Planning in Peacetime

2. Ted van Essen. How to be an inFLUencer: the role of a general practitioner

3. George Kassianos. Vaccinations to consider before, during, and after pregnancy

4. Terho Heikkinen. Flu shots for children? Why this should be more on the radar

5. Peter Openshaw. A mucosal perspective on pandemics

6. Ed Hutchinson. Visualising Viruses

7. Colin Russell. Using mathematical modelling to predict virus evolution and inform pandemic response

8. Roman Prymula. Walk the talk on immunisation

9. Marco Goeijenbier. Spotlight On The Burden Of Flu For People Living With Diabetes

10. Stefania Maggi. A geriatrician’s insight into reducing the burden of disease in older adults

11. Gülsah Gabriel. How does a virus cause disease after transmission?

12. Paula Tähtinen. Respiratory tract infections in childrenour paediatrician’s insight and bold vision for the future

ESWI Respiratory Virus Summit

Pandemic Preparedness: Where Science and Policy Meet

The ESWI Respiratory Virus Summit, entitled Pandemic Preparedness: Where Science and Policy Meet, took place in Brussels and online on Tuesday 21 June 2022.

Held in the heart of EU headquarters, the scientific and policymaking communities discussed a wide range of themes including early warning systems, diagnostic platforms, pathogen discovery, mathematical models of epidemics, clinical trial platforms, nonpharmaceutical intervention strategies, pharmaceutical intervention and treatment strategies, public communication, and global cooperation.

Taking a One Health and Global Health approach, the summit explored requirements for prediction, planning and execution aspects of pandemic preparedness.

The seven keynote lectures in the morning session included “The role of the WHO in Pandemic Preparedness Planning” by

Dr. Maria Van Kerkhove of the WHO; “Future preparedness for newly emerging infectious diseases” by Prof. Zhengli Shi, of the Wuhan Institute of Virology; and “The role of scientists in advising policymakers in a pandemic, what do we do now? How do we make it work?” by Prof. David Fisman, of the University of Toronto’s Dalla Lana School of Public Health.

An expert panel added their views on preparedness in the afternoon, including Dr. Wolfgang Philipp, the acting director of the European Commission’s DG Health Emergency Preparedness and Response Authority (HERA), followed by stakeholder debate with all panellists, keynote speakers and participants.

The main outcomes and recommendations of the ESWI Summit were published as a peerreviewed article in the scientific journal One Health Outlook.

PANDEMIC PREPAREDNESS: WHERE SCIENCE AND POLICY MEET

chaired by

Ab Osterhaus

ESWI CHAIR, TIHO, GERMANY

Colin Russell

ACADEMIC MEDICAL CENTER, UNIVERSITY OF AMSTERDAM

Debora MacKenzie

SCIENCE JOURNALIST

SPECIALISING IN INFECTIOUS DISEASES

09:00 – 10:30

KEYNOTE LECTURES

The role of WHO in Pandemic Preparedness Planning

Dr. Maria Van Kerkhove WHO, SWITZERLAND

Future preparedness for newly emerging infectious diseases

Prof. Zhengli Shi WUHAN INSTITUTE OF VIROLOGY, CHINA

HERA: what’s new in pandemic preparedness?

Dr. Wolfgang Philipp HERA, BELGIUM

10:30 – 11:00

11:00 – 13:00

COFFEE BREAK

KEYNOTE LECTURES

Options for global and accessible vaccines

Dr. Rino Rappuoli, GSK, ITALY

Translating Science to policymakers and the public at large

Prof. Christian Drosten CHARITÉ UNIVERSITÄTSMEDIZIN BERLIN, GERMANY

The role of scientists in advising policymakers in a pandemic, what do we do now? How do we make it work?

Prof. David Fisman UNIVERSITY OF TORONTO’S DALLA LANA SCHOOL OF PUBLIC HEALTH, CANADA

Making the International Health Regulations work?

Prof. David Heymann CHATHAM HOUSE, UNITED KINGDOM

13:00 – 14:00

14:00-14:15

LUNCH

RAPPORTEUR’S SUMMARY OF KEYNOTE LECTURES

Mrs. Debora Mackenzie SCIENCE JOURNALIST SPECIALISING IN INFECTIOUS DISEASE AND AUTHOR OF “STOPPING THE NEXT PANDEMIC”

14:15 – 15:15

EXPERT PANEL VIEWS ON PREPAREDNESS

Prof. Linfa Wang DUKE-NUS MEDICAL SCHOOL, SINGAPORE

Dr. Lwazi Manzi AU COMMISSION ON AFRICA’S COVID-19 RESPONSE, SOUTH AFRICA

Dr. Aeron Hurt, ROCHE, SWITZERLAND

Dr. Mark Eccleston-Turner KING’S COLLEGE LONDON, UNITED KINGDOM

15:15 – 15:45

15:45 – 17:15:

COFFEE BREAK

STAKEHOLDER DEBATE (ALL PARTICIPANTS)

Prof. Linfa Wang DUKE, SINGAPORE

Dr. Lwazi Manzi AU, AU COMMISSION ON AFRICA’S COVID-19 RESPONSE, SOUTH AFRICA

Dr. Aeron Hurt, ROCHE, SWITZERLAND

Dr. Mark Eccleston-Turner KING’S COLLEGE LONDON, UNITED KINGDOM

Prof. Christian Drosten, CHARITÉ UNIVERSITÄTSMEDIZIN BERLIN, GERMANY

Prof. David Fisman UNIVERSITY OF TORONTO’S DALLA LANA SCHOOL OF PUBLIC HEALTH, CANADA

17:15 – 17:30

CONCLUSIONS

Prof. Ab Osterhaus, ESWI CHAIR, TIHO, GERMANY

Prof. Colin Russell ESWI BOARD MEMBER, ACADEMIC MEDICAL CENTER, UNIVERSITY OF AMSTERDAM

Mrs. Debora MacKenzie SCIENCE JOURNALIST

Numbers at a glance

■ 9 Fluzines were sent to a database of over 19.000 contacts

■ More than 500 people registered from more than 66 countries

■ 7.666 pageviews of the Respiratory Virus Summit website

■ 936 total views via video on demand, from 21 June to 31 August

ESWI Website Education Hub

A major transformation of the ESWI website took place in 2022, which now features a comprehensive Education Hub. It provides a unique open access portal for acute respiratory virus information and includes a user-friendly search engine -searchable by keyword, topic, medium, risk group/NCD, network. It aims to become THE Educational Reference Centre for ESWI’s main target audience: scientists, clinicians, policymakers, but also for the general public. The Education Hub provides links to important scientific papers, reviewed by the ESWI Board members, and other online educational activities such as podcasts, webinars, recordings of conferences, summits, policy recommendations, reports, awareness campaigns, articles , etc.

More than 4.200 views since the new website was launched in October 2022.

Vaccination of specialrisk groups: A toolkit for pharmacists by the International Pharmaceutical Federation (FIP)

It summarises key information, practice guidelines and additional resources in a very practical manner. The Influenza Diabetes Community (IDC) has contributed to the chapter on people living with diabetes.

READ MORE

The cost of health care: how to make it affordable

Watch Robert Yates, political health economist specialising in Universal Health Coverage (UHC) at Chatham House, discuss with The Economist on the International UHC Day.

READ MORE

Older adults and COVID-19 vaccines

What do we know so far about older adults and COVID-19 vaccines? How long does the effect of the vaccine last and how successful have countries been in vaccinating older adults? WHO’s Dr Katherine O’Brien explains in Science in 5

READ MORE

“Flu, COVID and RSV: How to vaccinate?”

symposium at Options XI 30 years of ESWI

READ MORE

Council calls for combatting vaccine hesitancy and closer EU cooperation

EU Ministers of Health approved Council conclusions on vaccination as one of the most effective tools for preventing disease and improving public health.

READ MORE

Why Are Lots of Kids

Likely to Be Sick This Holiday Season?

Opinion by Florian Krammer and Aubree Gordon

READ MORE

The Health System

Burden of RSV in Europe

European Health Management Association’s (EHMA) white paper on the health system burden of the Respiratory syncytial virus (RSV) in Europe.

READ MORE

Stay Safe, Stay Well

Do you love to travel? Check out your recommended travel vaccinations to prevent contracting serious disease.

READ MORE

A few visuals as examples of educational tools covering RSV, Influenza and Covid-19.

EU Global Health Strategy to improve global health security and deliver better health for all

On 30 November, The European Commission adopted Europe’s agenda for global health action for the next 10 years.

READ MORE

National influenza surveillance systems in five European countries: a qualitative comparative framework based on WHO guidance

A new framework can be used to compare influenza surveillance systems qualitatively between countries to allow the identification of structural differences as well as to evaluate adherence to WHO guidance.

READ MORE

ESWI Communications

Social media

ESWI continues to create, collect and disseminate relevant scientific content, policy news and health related information about influenza, RSV and COVID-19 with three important objectives:

■ to reinforce ESWI’s presence and increase awareness

■ to increase interaction with target audiences

■ to promote ESWI events and other relevant events

@ESWInfluenza company/eswi

@ESWInfluenza

Fluzine: ESWI Newsletter

ESWI manages a database of over 19.000 stakeholders worldwide active in influenza, RSV and COVID-19 which comprises scientists, healthcare professionals, policymakers, and industry amongst others.

ESWI uses this platform (Fluzine) on a monthly basis to raise visibility of innovative research related to influenza, RSV and COVID-19, but also to share awareness raising campaigns and to disseminate educational projects and events.

Fluzine is an online tool that makes it easy for ESWI to communicate with health-related interest groups and update them on its regular activities, coalition partners and IDC members. Furthermore, it complements other communications tools such as the Education Hub, the ESWI website, the social media channels, and other publications.

ESWI in the media

JUNE 2022

Monkeypox makes pledges of pandemic solidarity look hollow

“At a pandemic preparedness conference I attended in Brussels last week, few scientists were prepared to rule out a monkeypox pandemic. A big theme of the conference, focused on respiratory viruses, was ensuring that the mistakes of Covid-19, such as delayed reporting of cases and poor messaging, are not repeated. One proposed remedy is the WHO pandemic preparedness treaty, sometimes called a global pandemic treaty. The treaty would legally bind signatories to such practices as timely data-sharing. A “zero draft” will come out in August. The treaty is already the subject of false claims that claim it will strip states of sovereignty and mandate imprisonment for the unvaccinated. The real obstacles are more prosaic: since the WHO is a technical agency rather than a legal one, could it enforce treaty obligations?”

JUNE 2022 • ESWI PRESS RELEASE

International community will gather in Brussels to discuss pandemic preparedness.

On 21 June, ESWI hosted a summit on the continuing pandemic threat posed by respiratory viruses, entitled “Pandemic Preparedness: Where Science and Policy Meet”. Experts from the Wuhan Institute of Virology, the World Health Organisation (WHO), the EU’s new Health Emergency Preparedness and Response unit (HERA), the African Union (AU) and other institutions participated in a discussion aimed at formulating a set of recommendations on predicting, planning, and responding to future pandemics.

OCTOBER 2022 • ESWI PRESS RELEASE

Pandemic Preparedness: Where Science and Policy Meet.

ESWI took part in the WHO public hearing on a new international instrument on pandemic prevention, preparedness and response, 29-30 September 2022.

Young Scientists

In October 2022, ESWI opened the call for applications for the 2023 Claude Hannoun Prize for Best Body of Work and the Young Scientist Vaccine Innovation Award. These awards form a central part of the Young Scientist Programme which was launched by ESWI in 2009. With the Claude Hannoun Prize for Best Body of Work, ESWI highlights and drives the work of young scientists in the field of respiratory virus infections. To broaden the network and with the support of CLS Seqirus, ESWI launched the Young Scientist Vaccine Innovation Award in 2020, recognising exceptional research by promising young scientists in the field of influenza vaccine development.

The Young scientist travel fund is geared towards supporting the travel and registration costs of young scientists at the conferences.

Influenza Diabetes Community

People with diabetes face a higher risk for acute respiratory virus infections and national and international guidelines advise that diabetes patients be annually vaccinated against influenza. The attention for the impact of influenza on people living with diabetes, however, is low and so is the vaccine uptake in this group.

In October 2017 leading diabetes organisations and ESWI joined forces to forge an active InfluenzaDiabetes Community (IDC) to raise awareness of the impact of influenza on people living with diabetes.

ESWI serves as its Secretariat and the IDC is chaired by ESWI Board Member, Marco Goeijenbier. The Community is successful and growing. It has been supported by Sanofi Pasteur since its inception and an outreach towards coalition partners and relevant stakeholders is also part of IDC activities. The IDC is open to new supporters and members that share the IDC vision and mission.

Annual work plans include regular meetings with invited guest lectures, overviews of recently published scientific articles and discussions and exchanges among Community members of best practices, campaigns, and webinars.

As a result of an important partnership with IDC Member FIP (International Pharmaceutical Federation), IDC co-produced a chapter on people living with diabetes in the FIP publication “Vaccination of special risk groups - A toolkit for pharmacists” with the objective to help pharmacists explain the importance of vaccination. As part of the World Diabetes Day activities, Marco Goeijenbier participated as panellist in the webinar “Vaccines & special-risk groups: Diabetes” organised by FIP. Another activity was the production of a podcast: “Spotlight on the burden of flu for people living with diabetes”. It featured Dan Howarth (Diabetes UK), Kirsty Short (University of Queensland) and Marco Goeijenbier discussing and addressing the following questions: Why are people with diabetes more at risk from flu? What are the options for reducing the risk? What are the challenges and solutions to increase awareness across health care professionals, researchers and patients themselves? How did COVID-19 change the attention to viral infections in risk groups?

Current Influenza/Diabetes community members are:

■ The International Diabetes Federation (IDF Europe)

■ Foundation of European Nurses in Diabetes (FEND)

■ Pharmacist Group to the European Union (PGEU)

■ Diabetes UK

■ Primary Care Diabetes Europe (PCDE)

■ Immunology of Diabetes Society (IDS)

■ European Association for the Study of Diabetes (EASD)

■ Nurse Practitioner Healthcare Foundation (NPHF)

■ Association of Diabetes Care and Education Specialists (ADCES)

■ American Pharmacists Association (APhA)

■ International Federation of Ageing (IFA)

■ Ministry of Public Health of the Sultanate of Oman

■ Federaçion Espanola de Diabetes (FEDE)

■ International Pharmaceutical Federation (FIP)

■ University of Queensland, School of Chemistry and Molecular Biosciences

■ Alliance for European Diabetes Research (EURADIA)

■ European Coalition for Diabetes (ECD)

■ Diabetes Liga

■ National Foundation for Infectious Diseases (NFID)

■ University of Rijeka (UNIRI), Department of Histology and Embryology

■ Center for Sustainable Health Care Quality and Equity (SHC)

■ #TogetherAgainstFlu

A dedicated website serves as a virtual reference centre for data and news on diabetes and influenza and other respiratory virus infections.

www.influenzadiabetescommunity.org

ESWI Symposium at OPTIONS XI

Commemorating 30 years of the European Scientific Working group on Influenza and other Respiratory Viruses, ESWI organised a symposium on “Flu, Covid-19 and RSV: How to vaccinate?” The event took place at the Options XI for the Control on Influenza conference, which took place in Belfast on 26-29 September.

Chaired by Colin Russell, ESWI Vice-Chair (Amsterdam University Medical Centre), the panel had Ab Osterhaus, ESWI Chair (TiHO), Peter Openshaw, ESWI Board Member (Imperial College), Adolfo

Garcia-Sastre, Icahn School of Medicine at Mount Sinai, and Kanta

Subbarao, WHO Collaborating Centre for Reference and Research on Influenza Melbourne, as speakers.

The challenges of immunising against all three respiratory viruses especially for vulnerable groups are more apparent than ever. The symposium looked at preventive action through joined-up vaccination campaigns, innovation in vaccines, and treatment options, and underlined the emphasis on awareness and preparedness.

Watch the symposium

https://eswi.org/cnt/article/flu-covid-and-rsvhow-vaccinate-symposium-options-xi-373

The 9th ESWI Influenza Conference 2023

ESWI is looking forward to the 9th ESWI Influenza Conference in Valencia from 17 - 20 September 2023 which will give the floor to the most renowned influenza, RSV and COVID-19 scientists, public health experts and healthcare professionals, discussing hot topics in epidemic and pandemic flu, RSV and COVID-19. As always, the conference will have two science tracks and one track designed to translate the science to policy.

The Scientific Programme Committee is working well and the preliminary conference schedule is live on the ESWI Conference website. Since November, the call for abstracts is open: deadline for submission of abstracts is 14 May 2023 at 23:59 CET The deadline for late breaker abstracts is 6 August 2023 at 23:59 CET.

In September, a successful site visit to Valencia by the ESWI Secretariat together with the technical team took place. We held several meetings with local partners, including the Valencia Conference Centre, and the aim is to deliver an outstanding 9th ESWI Influenza Conference in 2023.

INFLUENZA RSV DISEASE COVID-19

17-20 SEPTEMBER 2023 | VALENCIA

ESWI Respiratory Virus Summit 2023

The burden of RSV Disease and new intervention strategies

In 2022 the foundations were laid for the forthcoming Respiratory Virus Summit, entitled “The burden of RSV Disease and new intervention strategies”. It will take place in Brussels in June 2023. Themes of the summit will include burden of disease, epidemiology, surveillance, diagnostics, prevention and treatment.

The burden of RSV Disease and new intervention strategies

ESWI thanks the entire community of members, coalition partners and sponsors for the great collaboration in 2022. 2023 is set to be another interesting, busy and fruitful year. To realise our goals and meet our ambitious objectives, ESWI will continue to rely on our partners. Our joint forces are the strength of ESWI, allowing the organisation to play a unique role in the field of influenza and respiratory virus infections.