| 772 | France |
| 743 | Humans |
| 558 | Influenza, Human |
| 374 | Female |
| 350 | Male |
| 322 | Adult |
| 283 | Middle Aged |
| 252 | Aged |
| 237 | Influenza Vaccines |
| 203 | Adolescent |
| 195 | Influenza A Virus, H1N1 Subtype |
| 195 | Disease Outbreaks |
| 189 | Child |
| 166 | Vaccination |
| 157 | Young Adult |
| 149 | Child, Preschool |
| 137 | Seasons |
| 133 | Infant |
| 110 | Aged, 80 and over |
| 88 | Animals |
| 86 | Population Surveillance |
| 82 | Pandemics |
| 79 | Risk Factors |
| 74 | Infant, Newborn |
| 73 | Influenza A virus |
| 65 | Incidence |
| 64 | Prospective Studies |
| 63 | Respiratory Tract Infections |
| 56 | Surveys and Questionnaires |
| 56 | Cross-Sectional Studies |
| 54 | Retrospective Studies |
| 53 | Time Factors |
| 47 | Age Factors |
| 42 | Pregnancy |
| 42 | Hospitalization |
| 41 | Antiviral Agents |
| 38 | Influenza in Birds |
| 36 | Health Knowledge, Attitudes, Practice |
| 34 | Paris |
| 34 | Influenza B virus |
| 34 | Attitude of Health Personnel |
| 33 | Cohort Studies |
| 32 | Influenza A Virus, H3N2 Subtype |
| 32 | Antibodies, Viral |
| 31 | Treatment Outcome |
| 31 | Sentinel Surveillance |
| 30 | Orthomyxoviridae Infections |
| 28 | Patient Acceptance of Health Care |
| 28 | Orthomyxoviridae |
| 28 | Health Personnel |
| 27 | Oseltamivir |
| 27 | Influenza A Virus, H5N1 Subtype |
| 25 | Phylogeny |
| 24 | Virus Diseases |
| 24 | Reverse Transcriptase Polymerase Chain Reaction |
| 24 | Epidemics |
| 23 | Models, Statistical |
| 23 | Emergency Service, Hospital |
| 22 | United Kingdom |
| 22 | Severity of Illness Index |
| 22 | Risk Assessment |
| 22 | Public Health |
| 21 | Prevalence |
| 21 | Pregnancy Complications, Infectious |
| 21 | Cross Infection |
| 20 | Travel |
| 20 | Pneumococcal Vaccines |
| 20 | Immunization Programs |
| 20 | Hemagglutination Inhibition Tests |
| 20 | Birds |
| 20 | Anti-Bacterial Agents |
| 20 | Age Distribution |
| 19 | Sensitivity and Specificity |
| 19 | Hospitals, University |
| 19 | History, 20th Century |
| 18 | Practice Patterns, Physicians' |
| 18 | Neuraminidase |
| 18 | Attitude to Health |
| 17 | United States |
| 17 | Pneumonia, Viral |
| 17 | Intensive Care Units |
| 16 | Swine |
| 16 | Polymerase Chain Reaction |
| 16 | Mortality |
| 16 | Military Personnel |
| 15 | Personnel, Hospital |
| 15 | Logistic Models |
| 15 | General Practitioners |
| 15 | Follow-Up Studies |
| 15 | Communicable Diseases |
| 15 | Communicable Disease Control |
| 15 | Air Pollutants |
| 14 | Saudi Arabia |
| 14 | Respiratory Syncytial Virus Infections |
| 14 | RNA, Viral |
| 14 | Multivariate Analysis |
| 14 | Mass Vaccination |
| 14 | Health Policy |
| 14 | Europe |
| 14 | Coronavirus Infections |
| 14 | Community-Acquired Infections |
| 14 | Case-Control Studies |
| 13 | Viruses |
| 13 | Vaccines |
| 13 | Vaccination Coverage |
| 13 | Sequence Analysis, DNA |
| 13 | Pneumonia |
| 13 | Nursing Homes |
| 13 | General Practice |
| 13 | Epidemiological Monitoring |
| 13 | Comorbidity |
| 12 | Socioeconomic Factors |
| 12 | Regression Analysis |
| 12 | Nasopharynx |
| 12 | Infection Control |
| 12 | Immunization Schedule |
| 12 | Horses |
| 12 | Homes for the Aged |
| 12 | Ducks |
| 12 | Air Pollution |
| 11 | Zanamivir |
| 11 | Swine Diseases |
| 11 | Risk |
| 11 | Primary Health Care |
| 11 | Odds Ratio |
| 11 | Molecular Sequence Data |
| 11 | Internet |
| 11 | Horse Diseases |
| 11 | Hemagglutinin Glycoproteins, Influenza Virus |
| 11 | Health Care Surveys |
| 11 | Data Collection |
| 11 | Asthma |
| 10 | Urban Population |
| 10 | Reproducibility of Results |
| 10 | Physicians, Family |
| 10 | Interviews as Topic |
| 10 | Health Surveys |
| 10 | Global Health |
| 10 | Geriatrics |
| 10 | Forecasting |
| 10 | Databases, Factual |
| 10 | Cost of Illness |
| 10 | Algorithms |
| 9 | Viral Proteins |
| 9 | Sex Factors |
| 9 | Seroepidemiologic Studies |
| 9 | Rhinovirus |
| 9 | Practice Guidelines as Topic |
| 9 | Poultry |
| 9 | Poultry Diseases |
| 9 | Models, Theoretical |
| 9 | Longitudinal Studies |
| 9 | Immunocompromised Host |
| 9 | Health Promotion |
| 9 | HIV Infections |
| 9 | Germany |
| 9 | Geography |
| 9 | Family Practice |
| 9 | Epidemiologic Methods |
| 9 | Enzyme-Linked Immunosorbent Assay |
| 9 | Decision Making |
| 9 | Coinfection |
| 9 | Chronic Disease |
| 9 | Acute Disease |
| 8 | World Health Organization |
| 8 | Vaccines, Inactivated |
| 8 | Survival Analysis |
| 8 | Sulfur Dioxide |
| 8 | Pulmonary Disease, Chronic Obstructive |
| 8 | Pneumococcal Infections |
| 8 | Molecular Diagnostic Techniques |
| 8 | Models, Biological |
| 8 | Islam |
| 8 | Immunization |
| 8 | History, 21st Century |
| 8 | Drug Prescriptions |
| 8 | Diagnosis, Differential |
| 8 | Cost-Benefit Analysis |
| 8 | Cause of Death |
| 8 | Cardiovascular Diseases |
| 8 | Antigens, Viral |
| 7 | Turkeys |
| 7 | Sex Distribution |
| 7 | Respiratory Syncytial Viruses |
| 7 | Respiratory Distress Syndrome, Adult |
| 7 | Registries |
| 7 | Real-Time Polymerase Chain Reaction |
| 7 | Poisson Distribution |
| 7 | Pharmacovigilance |
| 7 | Patient Compliance |
| 7 | Nitrogen Dioxide |
| 7 | National Health Programs |
| 7 | Motivation |
| 7 | Length of Stay |
| 7 | Health Behavior |
| 7 | Feasibility Studies |
| 7 | Cystic Fibrosis |
| 7 | Computer Systems |
| 7 | Computer Simulation |
| 7 | Bacterial Infections |
| 7 | Antibodies, Bacterial |
| 7 | Amino Acid Substitution |
| 6 | Whooping Cough |
| 6 | Viral Vaccines |
| 6 | Urban Health |
| 6 | Statistics, Nonparametric |
| 6 | Space-Time Clustering |
| 6 | Sick Leave |
| 6 | Self Report |
| 6 | Reunion |
| 6 | Pneumonia, Pneumococcal |
| 6 | Pneumonia, Bacterial |
| 6 | Picornaviridae Infections |
| 6 | Outcome Assessment, Health Care |
| 6 | Mass Media |
| 6 | Masks |
| 6 | Immunosuppressive Agents |
| 6 | Hospitals |
| 6 | Hospital Units |
| 6 | Hospital Mortality |
| 6 | Guillain-Barre Syndrome |
| 6 | Genotype |
| 6 | Family Characteristics |
| 6 | Evolution, Molecular |
| 6 | Environmental Exposure |
| 6 | Emergency Medical Services |
| 6 | Demography |
| 6 | Cough |
| 6 | Confidence Intervals |
| 6 | Common Cold |
| 6 | Belgium |
| 6 | Animal Migration |
| 5 | Virology |
| 5 | Temperature |
| 5 | Streptococcus pneumoniae |
| 5 | Spatio-Temporal Analysis |
| 5 | Spain |
| 5 | Schools |
| 5 | Respiratory Tract Diseases |
| 5 | Recurrence |
| 5 | Reagent Kits, Diagnostic |
| 5 | Qualitative Research |
| 5 | Purpura, Thrombocytopenic, Idiopathic |
| 5 | Public Opinion |
| 5 | Program Evaluation |
| 5 | Probability |
| 5 | Pregnancy Outcome |
| 5 | Predictive Value of Tests |
| 5 | Pilot Projects |
| 5 | Pharmacists |
| 5 | Patient Education as Topic |
| 5 | Paramyxoviridae Infections |
| 5 | Ozone |
| 5 | Netherlands |
| 5 | Nervous System Diseases |
| 5 | Nasal Mucosa |
| 5 | Multiplex Polymerase Chain Reaction |
| 5 | Meteorological Concepts |
| 5 | Measles |
| 5 | Lung Diseases |
| 5 | Italy |
| 5 | Influenza A Virus, H5N2 Subtype |
| 5 | Immunization, Secondary |
| 5 | House Calls |
| 5 | Hemagglutinins, Viral |
| 5 | Health Status Indicators |
| 5 | Guideline Adherence |
| 5 | Fever |
| 5 | European Union |
| 5 | Enzyme Inhibitors |
| 5 | Drug Utilization |
| 5 | Drug Resistance, Viral |
| 5 | Dogs |
| 5 | Disease Transmission, Infectious |
| 5 | Disease Susceptibility |
| 5 | Developed Countries |
| 5 | Coronavirus |
| 5 | Cluster Analysis |
| 5 | Betacoronavirus |
| 5 | Bacteria |
| 5 | Antibody Formation |
| 5 | Antibodies, Monoclonal |
| 5 | Ambulatory Care |
| 5 | Adrenal Cortex Hormones |
| 5 | Absenteeism |
| 4 | Zoonoses |
| 4 | Workforce |
| 4 | Weather |
| 4 | Warfare |
| 4 | Thogotovirus |
| 4 | Tetanus Toxoid |
| 4 | Species Specificity |
| 4 | Societies, Medical |
| 4 | Sialic Acids |
| 4 | Respiratory Syncytial Virus, Human |
| 4 | Research Design |
| 4 | Refusal to Participate |
| 4 | Reassortant Viruses |
| 4 | Quality of Life |
| 4 | Public Health Surveillance |
| 4 | Proportional Hazards Models |
| 4 | Preventive Medicine |
| 4 | Population Dynamics |
| 4 | Poliomyelitis |
| 4 | Point-of-Care Systems |
| 4 | Pharmacies |
| 4 | Occupational Health |
| 4 | Occupational Diseases |
| 4 | Nurses |
| 4 | Nasal Cavity |
| 4 | Mutation, Missense |
| 4 | Mumps |
| 4 | Military Medicine |
| 4 | Midwifery |
| 4 | Metapneumovirus |
| 4 | Medical Staff, Hospital |
| 4 | Insurance, Health |
| 4 | Inpatients |
| 4 | Influenzavirus C |
| 4 | Influenza A Virus, H5N8 Subtype |
| 4 | Influenza A Virus, H1N2 Subtype |
| 4 | Infectious Disease Transmission, Professional-to-Patient |
| 4 | Hospitals, Public |
| 4 | History, Modern 1601- |
| 4 | History, 19th Century |
| 4 | Health Planning |
| 4 | Health Facilities |
| 4 | Genome, Viral |
| 4 | Feces |
| 4 | Fear |
| 4 | Epidemiologic Studies |
| 4 | Enterovirus Infections |
| 4 | Drug-Related Side Effects and Adverse Reactions |
| 4 | Double-Blind Method |
| 4 | Disease Reservoirs |
| 4 | Disaster Planning |
| 4 | Diphtheria-Tetanus-Pertussis Vaccine |
| 4 | Diabetes Mellitus |
| 4 | Data Interpretation, Statistical |
| 4 | Computer Communication Networks |
| 4 | Complement Fixation Tests |
| 4 | Communicable Diseases, Emerging |
| 4 | Cloaca |
| 4 | China |
| 4 | Cattle |
| 4 | Biomarkers |
| 4 | Base Sequence |
| 4 | Bacterial Vaccines |
| 4 | Australia |
| 4 | Anseriformes |
| 4 | Animals, Wild |
| 4 | Amino Acid Sequence |
| 4 | Adverse Drug Reaction Reporting Systems |
| 4 | Adjuvants, Immunologic |
| 3 | Virus Shedding |
| 3 | Virulence |
| 3 | Trachea |
| 3 | Tetanus |
| 3 | Telephone |
| 3 | Syndrome |
| 3 | Symptom Assessment |
| 3 | Switzerland |
| 3 | Suicide |
| 3 | Students, Nursing |
| 3 | Stroke |
| 3 | Stochastic Processes |
| 3 | Statistics as Topic |
| 3 | Staphylococcus aureus |
| 3 | Splenectomy |
| 3 | Smoke |
| 3 | Smallpox |
| 3 | Single-Blind Method |
| 3 | Serologic Tests |
| 3 | Sampling Studies |
| 3 | Rubella |
| 3 | Rituximab |
| 3 | Risk Management |
| 3 | Respirovirus Infections |
| 3 | Respiration, Artificial |
| 3 | Residence Characteristics |
| 3 | Recombination, Genetic |
| 3 | Quebec |
| 3 | Pyrans |
| 3 | Public Policy |
| 3 | Public Health Informatics |
| 3 | Psoriasis |
| 3 | Prenatal Care |
| 3 | Pregnant Women |
| 3 | Population |
| 3 | Policy Making |
| 3 | Plague |
| 3 | Physicians |
| 3 | Pertussis Vaccine |
| 3 | Perception |
| 3 | Pediatrics |
| 3 | Patient Satisfaction |
| 3 | Patient Safety |
| 3 | Patient Participation |
| 3 | Patient Isolation |
| 3 | Patient Admission |
| 3 | Particulate Matter |
| 3 | Parents |
| 3 | Oxygen Inhalation Therapy |
| 3 | Outpatients |
| 3 | Organ Dysfunction Scores |
| 3 | Online Systems |
| 3 | Occupational Exposure |
| 3 | Obesity |
| 3 | Nursing Staff, Hospital |
| 3 | Nurse's Role |
| 3 | Mutation |
| 3 | Multiple Sclerosis |
| 3 | Morbidity |
| 3 | Monte Carlo Method |
| 3 | Molecular Typing |
| 3 | Models, Econometric |
| 3 | Microbial Sensitivity Tests |
| 3 | Meta-Analysis as Topic |
| 3 | Meningococcal Infections |
| 3 | Mass Screening |
| 3 | Markov Chains |
| 3 | Lung |
| 3 | Linear Models |
| 3 | Leukocidins |
| 3 | Kaplan-Meier Estimate |
| 3 | Japan |
| 3 | Internal Medicine |
| 3 | Intensive Care Units, Pediatric |
| 3 | Intensive Care Units, Neonatal |
| 3 | Inhibitory Concentration 50 |
| 3 | Influenzavirus A |
| 3 | Influenza A Virus, H3N8 Subtype |
| 3 | Infectious Disease Transmission, Patient-to-Professional |
| 3 | Infections |
| 3 | Hygiene |
| 3 | Humidity |
| 3 | Hospital Departments |
| 3 | Homeless Persons |
| 3 | History, 18th Century |
| 3 | Hepatitis B Vaccines |
| 3 | Hemagglutination Tests |
| 3 | Heart Diseases |
| 3 | Health Services for the Aged |
| 3 | Health Care Costs |
| 3 | Guanidines |
| 3 | Genetic Variation |
| 3 | Gastrointestinal Diseases |
| 3 | Gastroenteritis |
| 3 | Extracorporeal Membrane Oxygenation |
| 3 | Expert Testimony |
| 3 | Exotoxins |
| 3 | Evaluation Studies as Topic |
| 3 | Environmental Monitoring |
| 3 | England |
| 3 | Emergencies |
| 3 | Early Diagnosis |
| 3 | Dust |
| 3 | Drug Therapy, Combination |
| 3 | Drug Industry |
| 3 | Drug Approval |
| 3 | Diphtheria Toxoid |
| 3 | Diarrhea |
| 3 | Diagnostic Tests, Routine |
| 3 | Death Certificates |
| 3 | Critical Illness |
| 3 | Contact Tracing |
| 3 | Community Networks |
| 3 | Commerce |
| 3 | Clinical Trials as Topic |
| 3 | Climate |
| 3 | Cities |
| 3 | Cell Line |
| 3 | Causality |
| 3 | Cattle Diseases |
| 3 | Bacterial Toxins |
| 3 | Arthritis, Rheumatoid |
| 3 | Anxiety |
| 3 | Antibodies, Neutralizing |
| 3 | Animal Husbandry |
| 3 | Analysis of Variance |
| 3 | Ambulatory Care Facilities |
| 3 | Amantadine |
| 3 | Administration, Intranasal |
| 3 | Adenoviridae Infections |
| 2 | World War I |
| 2 | Workplace |
| 2 | Whole Genome Sequencing |
| 2 | Wetlands |
| 2 | Water Microbiology |
| 2 | Vulnerable Populations |
| 2 | Viral Load |
| 2 | Viral Hepatitis Vaccines |
| 2 | Vaccines, Combined |
| 2 | Vaccines, Attenuated |
| 2 | Vaccine Potency |
| 2 | Vaccination Refusal |
| 2 | Universities |
| 2 | Uncertainty |
| 2 | Typhus, Epidemic Louse-Borne |
| 2 | Tuberculosis |
