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1.
CPT Pharmacometrics Syst Pharmacol ; 11(1): 44-54, 2022 01.
Article in English | MEDLINE | ID: covidwho-1616093

ABSTRACT

The identification of influenza epidemics and assessment of the efficacy of vaccination against this infection are major challenges for the implementation of effective public health strategies, such as vaccination programs. In this study, we developed a new pharmacometric model to evaluate the efficacy of vaccination based on infection surveillance data from the 2010/2011 to 2018/2019 influenza seasons in Japan. A novel susceptible-infected-removed plus vaccination model, based on an indirect response structure with the effect of vaccination, was applied to describe seasonal influenza epidemics using a preseasonal collection of data regarding serological H1 antibody titer positivity and the fraction of virus strains. Using this model, we evaluated Kin (a parameter describing the transmission rate of symptomatic influenza infection) for different age groups. Furthermore, we defined a new parameter (prevention factor) showing the efficacy of vaccination against each viral strain and in different age groups. We found that the prevention factor of vaccination against influenza varied among age groups. Notably, children aged 5-14 years showed the highest Kin value during the 10 influenza seasons and the greatest preventive effect of vaccination (prevention factor = 70.8%). The propagation of influenza epidemics varies in different age groups. Children aged 5-14 years most likely play a leading role in the transmission of influenza. Prioritized vaccination in this age group may be the most effective strategy for reducing the prevalence of influenza in the community.


Subject(s)
Influenza Vaccines/administration & dosage , Influenza Vaccines/immunology , Influenza, Human/epidemiology , Influenza, Human/immunology , Adolescent , Adult , Age Factors , Aged , Basic Reproduction Number , Child , Child, Preschool , Female , Humans , Infant , Influenza, Human/prevention & control , Influenza, Human/transmission , Japan/epidemiology , Male , Middle Aged , Models, Biological , Seasons , Sentinel Surveillance , Young Adult
3.
PLoS Pathog ; 17(12): e1010106, 2021 12.
Article in English | MEDLINE | ID: covidwho-1598647

ABSTRACT

The development of safe and effective vaccines in a record time after the emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a remarkable achievement, partly based on the experience gained from multiple viral outbreaks in the past decades. However, the Coronavirus Disease 2019 (COVID-19) crisis also revealed weaknesses in the global pandemic response and large gaps that remain in our knowledge of the biology of coronaviruses (CoVs) and influenza viruses, the 2 major respiratory viruses with pandemic potential. Here, we review current knowns and unknowns of influenza viruses and CoVs, and we highlight common research challenges they pose in 3 areas: the mechanisms of viral emergence and adaptation to humans, the physiological and molecular determinants of disease severity, and the development of control strategies. We outline multidisciplinary approaches and technological innovations that need to be harnessed in order to improve preparedeness to the next pandemic.


Subject(s)
COVID-19/virology , Influenza, Human/virology , Orthomyxoviridae/physiology , SARS-CoV-2/physiology , Animals , Antiviral Agents , COVID-19/therapy , COVID-19/transmission , Drug Development , Evolution, Molecular , Humans , Influenza, Human/therapy , Influenza, Human/transmission , Orthomyxoviridae/immunology , SARS-CoV-2/immunology , Selection, Genetic , Viral Load , Viral Vaccines
4.
J Infect Dis ; 224(9): 1500-1508, 2021 11 16.
Article in English | MEDLINE | ID: covidwho-1522219

ABSTRACT

BACKGROUND: Nonpharmaceutical interventions (NPIs) have been implemented to suppress transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Evidence indicates that NPIs against coronavirus disease 2019 (COVID-19) may also have effects on transmission of seasonal influenza. METHODS: In this study, we use an absolute humidity-driven susceptible-infectious-recovered-susceptible (SIRS) model to quantify the reduction of influenza incidence and transmission in the United States and US Department of Health and Human Services regions after implementation of NPIs in 2020. We investigate long-term effect of NPIs on influenza incidence by projecting influenza transmission at the national scale over the next 5 years, using the SIRS model. RESULTS: We estimate that incidence of influenza A/H1 and B, which circulated in early 2020, was reduced by more than 60% in the United States during the first 10 weeks following implementation of NPIs. The reduction of influenza transmission exhibits clear geographical variation. After the control measures are relaxed, potential accumulation of susceptibility to influenza infection may lead to a large outbreak, the scale of which may be affected by length of the intervention period and duration of immunity to influenza. CONCLUSIONS: Healthcare systems need to prepare for potential influenza patient surges and advocate vaccination and continued precautions.


Subject(s)
COVID-19/epidemiology , COVID-19/prevention & control , Forecasting , Influenza, Human/transmission , COVID-19/transmission , COVID-19/virology , Communicable Disease Control , Humans , Incidence , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Pandemics , Public Health , SARS-CoV-2/isolation & purification , United States/epidemiology
5.
Ann Intern Med ; 174(12): 1710-1718, 2021 12.
Article in English | MEDLINE | ID: covidwho-1506230

ABSTRACT

Policies to prevent respiratory virus transmission in health care settings have traditionally divided organisms into Droplet versus Airborne categories. Droplet organisms (for example, influenza) are said to be transmitted via large respiratory secretions that rapidly fall to the ground within 1 to 2 meters and are adequately blocked by surgical masks. Airborne pathogens (for example, measles), by contrast, are transmitted by aerosols that are small enough and light enough to carry beyond 2 meters and to penetrate the gaps between masks and faces; health care workers are advised to wear N95 respirators and to place these patients in negative-pressure rooms. Respirators and negative-pressure rooms are also recommended when caring for patients with influenza or SARS-CoV-2 who are undergoing "aerosol-generating procedures," such as intubation. An increasing body of evidence, however, questions this framework. People routinely emit respiratory particles in a range of sizes, but most are aerosols, and most procedures do not generate meaningfully more aerosols than ordinary breathing, and far fewer than coughing, exercise, or labored breathing. Most transmission nonetheless occurs at close range because virus-laden aerosols are most concentrated at the source; they then diffuse and dilute with distance, making long-distance transmission rare in well-ventilated spaces. The primary risk factors for nosocomial transmission are community incidence rates, viral load, symptoms, proximity, duration of exposure, and poor ventilation. Failure to appreciate these factors may lead to underappreciation of some risks (for example, overestimation of the protection provided by medical masks, insufficient attention to ventilation) or misallocation of limited resources (for example, reserving N95 respirators and negative-pressure rooms only for aerosol-generating procedures or requiring negative-pressure rooms for all patients with SARS-CoV-2 infection regardless of stage of illness). Enhanced understanding of the factors governing respiratory pathogen transmission may inform the development of more effective policies to prevent nosocomial transmission of respiratory pathogens.


Subject(s)
Infection Control/methods , Respiratory Tract Infections/transmission , Respiratory Tract Infections/virology , Aerosols , COVID-19/prevention & control , COVID-19/transmission , COVID-19/virology , Cross Infection/prevention & control , Cross Infection/virology , Health Policy , Humans , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Influenza, Human/prevention & control , Influenza, Human/transmission , Influenza, Human/virology , Masks , Personnel, Hospital , SARS-CoV-2 , United States/epidemiology , Ventilation
7.
Kidney Blood Press Res ; 46(5): 639-646, 2021.
Article in English | MEDLINE | ID: covidwho-1476898

ABSTRACT

BACKGROUND: It is just over a century since the 1918 flu pandemic, sometimes referred to as the "mother" of pandemics. This brief retrospective of the 1918 pandemic is taken from the viewpoint of the current SARS-CoV-2/COVID-19 pandemic and is based on a short lecture given during the 2021 Virtual Congress of the ERA-EDTA. SUMMARY: This review summarizes and highlights some of the earlier pandemic's salient features, some parallels with today, and some potential learnings, bearing in mind that the flu pandemic occurred over 100 years ago at a time of major turmoil during the climax to WWl, and with limited medical expertise and knowledge, research facilities, or well-structured and resourced healthcare services. While there is little or no information on renal complications at the time, or an effective treatment, some observations in relation to COVID-19 and vaccination are included. Key Messages: Lessons are difficult to draw from 1918 other than the importance and value of non-pharmaceutical measures to limit viral transmission. While the economic impact of the 1918 pandemic was significant, as it is now with COVID-19, subsequent economic analysis has shown that protecting public health and preserving economic activity are not mutually exclusive. Both H1N1 and SARS-CoV-2 viruses are neurotropic and may cause chronically debilitating neurological diseases, including conditions such as encephalitis lethargica (still debated) and myalgic encephalomyelitis (chronic fatigue syndrome), respectively. Although coronavirus and influenza viral infections have some similarities, they are certainly not the same, as we are realising, and future infectious pandemics may still surprise us, but being "forewarned is forearmed."


Subject(s)
COVID-19 , Influenza Pandemic, 1918-1919/history , Influenza, Human/transmission , Pandemics , COVID-19/complications , COVID-19/economics , History, 20th Century , History, 21st Century , Humans , Influenza A Virus, H1N1 Subtype , Influenza Pandemic, 1918-1919/economics
9.
J Infect Dis ; 224(9): 1500-1508, 2021 11 16.
Article in English | MEDLINE | ID: covidwho-1434407

ABSTRACT

BACKGROUND: Nonpharmaceutical interventions (NPIs) have been implemented to suppress transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Evidence indicates that NPIs against coronavirus disease 2019 (COVID-19) may also have effects on transmission of seasonal influenza. METHODS: In this study, we use an absolute humidity-driven susceptible-infectious-recovered-susceptible (SIRS) model to quantify the reduction of influenza incidence and transmission in the United States and US Department of Health and Human Services regions after implementation of NPIs in 2020. We investigate long-term effect of NPIs on influenza incidence by projecting influenza transmission at the national scale over the next 5 years, using the SIRS model. RESULTS: We estimate that incidence of influenza A/H1 and B, which circulated in early 2020, was reduced by more than 60% in the United States during the first 10 weeks following implementation of NPIs. The reduction of influenza transmission exhibits clear geographical variation. After the control measures are relaxed, potential accumulation of susceptibility to influenza infection may lead to a large outbreak, the scale of which may be affected by length of the intervention period and duration of immunity to influenza. CONCLUSIONS: Healthcare systems need to prepare for potential influenza patient surges and advocate vaccination and continued precautions.


Subject(s)
COVID-19/epidemiology , COVID-19/prevention & control , Forecasting , Influenza, Human/transmission , COVID-19/transmission , COVID-19/virology , Communicable Disease Control , Humans , Incidence , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Pandemics , Public Health , SARS-CoV-2/isolation & purification , United States/epidemiology
10.
Microbiol Spectr ; 9(2): e0025721, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1410327

ABSTRACT

Human-to-human transmission of viruses, such as influenza viruses and coronaviruses, can promote virus evolution and the emergence of new strains with increased potential for creating pandemics. Clinical studies analyzing how a particular type of virus progressively evolves new traits, such as resistance to antiviral therapies, as a result of passing between different human hosts are difficult to carry out because of the complexity, scale, and cost of the challenge. Here, we demonstrate that spontaneous evolution of influenza A virus through both mutation and gene reassortment can be reconstituted in vitro by sequentially passaging infected mucus droplets between multiple human lung airway-on-a-chip microfluidic culture devices (airway chips). Modeling human-to-human transmission of influenza virus infection on chips in the continued presence of the antiviral drugs amantadine or oseltamivir led to the spontaneous emergence of clinically prevalent resistance mutations, and strains that were resistant to both drugs were identified when they were administered in combination. In contrast, we found that nafamostat, an inhibitor targeting host serine proteases, did not induce viral resistance. This human preclinical model may be useful for studying viral evolution in vitro and identifying potential influenza virus variants before they appear in human populations, thereby enabling preemptive design of new and more effective vaccines and therapeutics. IMPORTANCE The rapid evolution of viruses, such as influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is challenging the use and development of antivirals and vaccines. Studies of within-host viral evolution can contribute to our understanding of the evolutionary and epidemiological factors that shape viral global evolution as well as development of better antivirals and vaccines. However, little is known about how viral evolution of resistance to antivirals occurs clinically due to the lack of preclinical models that can faithfully model influenza infection in humans. Our study shows that influenza viral evolution through mutation or gene reassortment can be recapitulated in a human lung airway-on-a-chip (airway chip) microfluidic culture device that can faithfully recapitulate the influenza infection in vitro. This approach is useful for studying within-host viral evolution, evaluating viral drug resistance, and identifying potential influenza virus variants before they appear in human populations, thereby enabling the preemptive design of new and more effective vaccines and therapeutics.


Subject(s)
Drug Resistance, Viral/genetics , Evolution, Molecular , Influenza A virus/drug effects , Influenza A virus/genetics , Lab-On-A-Chip Devices , Amantadine/pharmacology , Antiviral Agents/pharmacology , Benzamidines/pharmacology , Guanidines/pharmacology , Humans , Influenza, Human/drug therapy , Influenza, Human/transmission , Lung/virology , Microfluidics , Oseltamivir/pharmacology , SARS-CoV-2/genetics
12.
Elife ; 102021 02 23.
Article in English | MEDLINE | ID: covidwho-1389775

ABSTRACT

SARS-CoV-2 is difficult to contain because many transmissions occur during pre-symptomatic infection. Unlike influenza, most SARS-CoV-2-infected people do not transmit while a small percentage infect large numbers of people. We designed mathematical models which link observed viral loads with epidemiologic features of each virus, including distribution of transmissions attributed to each infected person and duration between symptom onset in the transmitter and secondarily infected person. We identify that people infected with SARS-CoV-2 or influenza can be highly contagious for less than 1 day, congruent with peak viral load. SARS-CoV-2 super-spreader events occur when an infected person is shedding at a very high viral load and has a high number of exposed contacts. The higher predisposition of SARS-CoV-2 toward super-spreading events cannot be attributed to additional weeks of shedding relative to influenza. Rather, a person infected with SARS-CoV-2 exposes more people within equivalent physical contact networks, likely due to aerosolization.


Subject(s)
COVID-19/transmission , Carrier State , Viral Load , Virus Shedding , Aerosols , Basic Reproduction Number , COVID-19/epidemiology , China/epidemiology , Computer Simulation , Contact Tracing , Humans , Influenza, Human/epidemiology , Influenza, Human/transmission , Models, Theoretical , Pandemics , Probability , SARS-CoV-2 , Time Factors
13.
Int J Infect Dis ; 104: 198-206, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1385702

ABSTRACT

INTRODUCTION: Synthesis of the available evidence on the effectiveness of medical and cloth facemask use by the general public in community settings is required to learn lessons for future respiratory epidemics/pandemics. METHOD: Search terms relating to facemasks, infection and community settings were used for PubMed, the Cochrane Library Database and Google Scholar. A meta-analysis was conducted using a random-effects model. RESULTS: The review included 12 primary studies on the effectiveness of medical facemask use to prevent influenza, influenza-like illness, SARS-CoV, and SARS-CoV-2 transmission. The meta-analysis demonstrated that facemask use significantly reduces the risk of transmitting these respiratory infections (pooled OR = 0.66, 95% CI 0.54-0.81). Of the 12 studies, 10 clinical trials suggested that respiratory infection incidence is lower with high medical facemask compliance, early use and use in combination with intensive hand hygiene. One cohort study conducted during the SARS-CoV-2 pandemic demonstrated that facemasks are effective in reducing SARS-CoV-2 transmission when used before those who are infected develop symptoms. One case-control study reported that controls used medical facemasks more often than cases infected with SARS-CoV (p < 0.05). No primary study on cloth facemask effectiveness to prevent respiratory infection transmission was found. CONCLUSION: Based on the available evidence, medical facemask use by healthy and sick individuals is recommended for preventing respiratory infection transmission in community settings. Medical facemask effectiveness is dependent on compliance and utilization in combination with preventive measures such as intensive hand hygiene. No direct evidence is currently available in humans supporting the recommendation of cloth facemask use to prevent respiratory infection transmission.


Subject(s)
COVID-19/prevention & control , Influenza, Human/prevention & control , Masks , Pandemics/prevention & control , Respiratory Tract Infections/prevention & control , Severe Acute Respiratory Syndrome/prevention & control , COVID-19/transmission , COVID-19/virology , Case-Control Studies , Cohort Studies , Hand Hygiene , Humans , Influenza, Human/transmission , Influenza, Human/virology , Respiratory Tract Infections/transmission , Respiratory Tract Infections/virology , Severe Acute Respiratory Syndrome/transmission , Severe Acute Respiratory Syndrome/virology
16.
Hist. ciênc. saúde-Manguinhos ; 28(3): 879-883, jul.-set. 2021.
Article in Spanish | WHO COVID, LILACS (Americas) | ID: covidwho-1341554

ABSTRACT

Resumen El desarrollo de la pandemia de la covid-19 ha motivado un renovado interés por la gripe de 1918-1919 para buscar elementos que facilitaran la comprensión de la experiencia presente, pero también como oportunidad para reevaluar la grave crisis sanitaria del siglo XX a la luz de lo que estamos viviendo. En este contexto y con ese objetivo se inserta esta reflexión histórica sobre estos dos fenómenos pandémicos, que muestra los paralelismos existentes y la necesidad de una toma de conciencia de que nuestro modelo de sociedad está en crisis y se requiere una transformación profunda.


Abstract The rise of the covid-19 pandemic has led to renewed interest in the 1918-1919 influenza in search of aspects that might help us understand the current situation, but also as an opportunity to re-evaluate the serious twentieth-century health crisis in light of what we are experiencing now. In this context and with that goal, this historical reflection shows the parallels that exist and the need for a realization that our model of society is undergoing a crisis and requires profound transformation.


Subject(s)
Humans , History, 20th Century , History, 21st Century , Influenza, Human/history , Pandemics/history , COVID-19/history , Influenza Vaccines/history , Hygiene/history , Denial, Psychological , World War I , Economics , Influenza, Human/prevention & control , Influenza, Human/transmission , Influenza, Human/epidemiology , COVID-19 Vaccines/history , COVID-19/prevention & control , COVID-19/transmission , COVID-19/epidemiology , Military Personnel/history
18.
Nat Commun ; 12(1): 3249, 2021 05 31.
Article in English | MEDLINE | ID: covidwho-1249208

ABSTRACT

Coronavirus disease 2019 (COVID-19) was detected in China during the 2019-2020 seasonal influenza epidemic. Non-pharmaceutical interventions (NPIs) and behavioral changes to mitigate COVID-19 could have affected transmission dynamics of influenza and other respiratory diseases. By comparing 2019-2020 seasonal influenza activity through March 29, 2020 with the 2011-2019 seasons, we found that COVID-19 outbreaks and related NPIs may have reduced influenza in Southern and Northern China and the United States by 79.2% (lower and upper bounds: 48.8%-87.2%), 79.4% (44.9%-87.4%) and 67.2% (11.5%-80.5%). Decreases in influenza virus infection were also associated with the timing of NPIs. Without COVID-19 NPIs, influenza activity in China and the United States would likely have remained high during the 2019-2020 season. Our findings provide evidence that NPIs can partially mitigate seasonal and, potentially, pandemic influenza.


Subject(s)
COVID-19/epidemiology , Influenza, Human/epidemiology , Models, Statistical , Pandemics , Respiratory Tract Infections/epidemiology , COVID-19/transmission , COVID-19/virology , China/epidemiology , Humans , Influenza, Human/transmission , Influenza, Human/virology , Orthomyxoviridae/pathogenicity , Orthomyxoviridae/physiology , Personal Protective Equipment , Physical Distancing , Quarantine/organization & administration , Respiratory Tract Infections/transmission , Respiratory Tract Infections/virology , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Seasons , United States/epidemiology
19.
Hum Genomics ; 15(1): 26, 2021 05 07.
Article in English | MEDLINE | ID: covidwho-1220117

ABSTRACT

BACKGROUND: Mathematical approaches have been for decades used to probe the structure of DNA sequences. This has led to the development of Bioinformatics. In this exploratory work, a novel mathematical method is applied to probe the DNA structure of two related viral families: those of coronaviruses and those of influenza viruses. The coronaviruses are SARS-CoV-2, SARS-CoV-1, and MERS. The influenza viruses include H1N1-1918, H1N1-2009, H2N2-1957, and H3N2-1968. METHODS: The mathematical method used is the slow feature analysis (SFA), a rather new but promising method to delineate complex structure in DNA sequences. RESULTS: The analysis indicates that the DNA sequences exhibit an elaborate and convoluted structure akin to complex networks. We define a measure of complexity and show that each DNA sequence exhibits a certain degree of complexity within itself, while at the same time there exists complex inter-relationships between the sequences within a family and between the two families. From these relationships, we find evidence, especially for the coronavirus family, that increasing complexity in a sequence is associated with higher transmission rate but with lower mortality. CONCLUSIONS: The complexity measure defined here may hold a promise and could become a useful tool in the prediction of transmission and mortality rates in future new viral strains.


Subject(s)
Betacoronavirus/classification , Betacoronavirus/genetics , Influenza A virus/classification , Influenza A virus/genetics , Models, Genetic , Betacoronavirus/physiology , Coronavirus Infections/mortality , Coronavirus Infections/transmission , Coronavirus Infections/virology , Evolution, Molecular , Humans , Influenza A virus/physiology , Influenza, Human/mortality , Influenza, Human/transmission , Influenza, Human/virology , Sequence Analysis, DNA , Species Specificity , Time Factors
20.
Aten Primaria ; 53(5): 102021, 2021 May.
Article in Spanish | MEDLINE | ID: covidwho-1196671

ABSTRACT

OBJECTIVE: The present study seeks to analyse sociodemographic determinants related to severe acute respiratory infections (SARI) and calculate the priorization index in the cantons of Ecuador to identify areas probably most vulnerable to COVID-19 transmission. DESIGN: This descriptive ecological observational study. SETTING: 224 cantons (geographical area) of Ecuador with secondary data sources of hospital information. PARTICIPANTS: The unit of measurement was 224 cantons of Ecuador, in which analysed morbidity and lethality rates for SARI using hospital release data (2016-2018). MAIN MEASUREMENTS: Eight sociodemographic indicators were structuralized, and correlation tests applied for a multiple regression model. The priorization index was created with criteria of efficiency, efficacy, effect size (IRR) and equity. Using the sum of the index for each indicator, the priorization score was calculated and localized in a territorial map. RESULTS: Morbidity associated factors where: school attendance years, urbanization and population density; for mortality resulted: school attendance and ethnics (indigenous) IRR: 1.09 (IC95%:1.06-1.15) and IRR: 1.024 (IC95%:102-1.03) respectively. With lethality where related cantons, with population older than 60 years, IRR: 1.049 (IC95%: 1.03-1.07); 87 cantons had high priority mostly localized in the mountain region and the Morona Santiago Province. CONCLUSIONS: Morbidity and mortality of SARI in Ecuador are associated to social and demographic factors. Priorization exercises considering these factors permit the identification of vulnerable territories facing respiratory disease propagation. The social determinants characteristic for each territory should be added to known individual factors to analyse the risk and vulnerability for COVID in the population.


Subject(s)
COVID-19/etiology , COVID-19/prevention & control , Social Determinants of Health , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/transmission , Child , Child, Preschool , Ecuador/epidemiology , Environment , Female , Geographic Mapping , Humans , Infant , Infant, Newborn , Influenza, Human/epidemiology , Influenza, Human/etiology , Influenza, Human/prevention & control , Influenza, Human/transmission , Male , Middle Aged , Pandemics , Risk Assessment , Risk Factors , Severity of Illness Index , Socioeconomic Factors , Vulnerable Populations , Young Adult
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