A pandemic is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide.
An epidemic is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic.
The 1918–1920 flu pandemic, also known as the Great Influenza epidemic or by the common misnomer Spanish flu, was an exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. The earliest documented case was March 1918 in the state of Kansas in the United States, with further cases recorded in France, Germany and the United Kingdom in April. Two years later, nearly a third of the global population, or an estimated 500 million people, had been infected in four successive waves. Estimates of deaths range from 17 million to 50 million, and possibly as high as 100 million, making it one of the deadliest pandemics in history.
Flu season is an annually recurring time period characterized by the prevalence of an outbreak of influenza (flu). The season occurs during the cold half of the year in each hemisphere. It takes approximately two days to show symptoms. Influenza activity can sometimes be predicted and even tracked geographically. While the beginning of major flu activity in each season varies by location, in any specific location these minor epidemics usually take about three weeks to reach its pinnacle, and another three weeks to significantly diminish.
Influenza prevention involves taking steps that one can use to decrease their chances of contracting flu viruses, such as the Pandemic H1N1/09 virus, responsible for the 2009 flu pandemic.
Richard Michael Durbin is a British computational biologist and Al-Kindi Professor of Genetics at the University of Cambridge. He also serves as an associate faculty member at the Wellcome Sanger Institute where he was previously a senior group leader.
Dame Angela Ruth McLean is professor of mathematical biology in the Department of Biology, University of Oxford, and Chief Scientific Adviser to the UK Government.
Bryan Thomas Grenfell is a British population biologist and the Kathryn Briger and Sarah Fenton Professor of Ecology and Evolutionary Biology and Public Affairs at the Princeton School of Public and International Affairs at Princeton University.
Sir Jeremy James Farrar is a British medical researcher who has served as chief scientist at the World Health Organization since 2023. He was previously the director of the Wellcome Trust from 2013 to 2023 and a professor of tropical medicine at the University of Oxford.
Sheila Macdonald Bird OBE FRSE FMedSci is a Scottish biostatistician whose assessment of misuse of statistics in the British Medical Journal (BMJ) and BMJ series ‘Statistics in Question’ led to statistical guidelines for contributors to medical journals. Bird's doctoral work on non-proportional hazards in breast cancer found application in organ transplantation where beneficial matching was the basis for UK's allocation of cadaveric kidneys for a decade. Bird led the Medical Research Council (MRC) Biostatistical Initiative in support of AIDS/HIV studies in Scotland, as part of which Dr A. Graham Bird and she pioneered Willing Anonymous HIV Surveillance (WASH) studies in prisons. Her work with Cooper on UK dietary bovine spongiform encephalopathy (BSE) exposure revealed that the 1940–69 birth cohort was the most exposed and implied age-dependency in susceptibility to clinical vCJD progression from dietary BSE exposure since most vCJD cases were younger, born in 1970–89. Bird also designed the European Union's robust surveillance for transmissible spongiform encephalopathies in sheep which revolutionised the understanding of scrapie.
Christl Ann Donnelly is a professor of statistical epidemiology at Imperial College London, the University of Oxford and a Fellow of St Peter's College, Oxford. She serves as associate director of the MRC Centre for Global Infectious Disease Analysis.
This is a timeline of influenza, briefly describing major events such as outbreaks, epidemics, pandemics, discoveries and developments of vaccines. In addition to specific year/period-related events, there is the seasonal flu that kills between 250,000 and 500,000 people every year and has claimed between 340 million and 1 billion human lives throughout history.
Guan Yi is a Chinese virologist. In 2014, he was ranked as 11th in the world by Thomson Reuters among global researchers in the field of microbiology. He obtained his PhD in microbiology at the University of Hong Kong and is now a professor of microbiology at his alma mater. His research on the viral respiratory disease SARS helped the Chinese government avert the 2004 outbreak of this disease. He is the current director of the State Key Laboratory for Emerging Infectious Diseases University of Hong Kong. In early 2017, Guan warned that the H7N9 influenza virus "poses the greatest threat to humanity than any other in the past 100 years".
Neil Morris Ferguson is a British epidemiologist and professor of mathematical biology, who specialises in the patterns of spread of infectious disease in humans and animals. He is the director of the Jameel Institute, and of the MRC Centre for Global Infectious Disease Analysis, and head of the Department of Infectious Disease Epidemiology in the School of Public Health and Vice-Dean for Academic Development in the Faculty of Medicine, all at Imperial College London.
Azra Catherine Hilary Ghani is a British epidemiologist who is a professor of Infectious Disease Epidemiology at Imperial College London. Her research considers the mathematical modelling of infectious diseases, including malaria, bovine spongiform encephalopathy and coronavirus. She has worked with the World Health Organization on their technical strategy for malaria. She is associate director of the MRC Centre for Global Infectious Disease Analysis.
Maria DeJoseph Van Kerkhove is an American infectious disease epidemiologist. With a background in high-threat pathogens, Van Kerkhove specializes in emerging and re-emerging infectious diseases and is based in the Health Emergencies Program at the World Health Organization (WHO). She is the technical lead of COVID-19 response and the head of emerging diseases and zoonosis unit at WHO.
Cécile Viboud is a Staff Scientist based in the Fogarty International Center at the National Institutes of Health, where she is part of the Multinational Influenza Seasonal Mortality Study (MISMS). Viboud specialises in the mortality of infectious disease. Viboud was involved with epidemiological analysis during the COVID-19 pandemic.
Eleni Nastouli is a Greek clinical virologist who works at University College London Hospitals NHS Foundation Trust (UCLH) and Great Ormond Street Hospital. At UCLH, Nastouli leads the Advanced Pathogen Diagnostics Unit, where she develops technologies for genome sequencing as well as studying how viruses are transmitted around hospitals. During the COVID-19 pandemic Nastouli led an investigation into infection rates amongst healthcare workers.
Shabir Ahmed Madhi is a South African physician who is professor of vaccinology and director of the South African Medical Research Council Respiratory and Meningeal Pathogens Research Unit at the University of the Witwatersrand, and National Research Foundation/Department of Science and Technology Research Chair in Vaccine Preventable Diseases. In January 2021, he was appointed Dean of the Faculty of Health Sciences at the University of the Witwateratand.
