Face masks to prevent transmission of influenza virus: a systematic review

SUMMARYInfluenza viruses circulate around the world every year. From time to time new strains emerge and cause global pandemics. Many national and international health agencies recommended the use of face masks during the 2009 influenza A (H1N1) pandemic. We reviewed the English-language literature on this subject to inform public health preparedness. There is some evidence to support the wearing of masks or respirators during illness to protect others, and public health emphasis on mask wearing during illness may help to reduce influenza virus transmission. There are fewer data to support the use of masks or respirators to prevent becoming infected. Further studies in controlled settings and studies of natural infections in healthcare and community settings are required to better define the effectiveness of face masks and respirators in preventing influenza virus transmission.

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Initial epidemiological findings in the European Union following the declaration of pandemic alert level 5 due to influenza A (H1N1)

Eurosurveillance ◽

10.2807/ese.14.18.19204-en ◽

2009 ◽

Vol 14 (18) ◽

Cited By ~ 3

Author(s):

ECDC Technical Emergency Team

Keyword(s):

Public Health ◽

Influenza A ◽

International Health ◽

The United States ◽

The European Union ◽

Public Health Agencies ◽

Influenza A H1n1 ◽

Health Agencies ◽

Health Event ◽

Health Regulations

The recent detection of a novel influenza A(H1N1) virus has led to the first WHO declaration of a Public Health Event of International Concern under the International Health Regulations (IHR 2005). Here we review the early epidemiological findings of confirmed cases in Mexico, the United States, Canada and EU/EFTA countries. Strengthened surveillance and continued, transparent communication across public health agencies globally will be necessary in coming months.

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Influenza: An Emerging and Re-emerging Public Health Threat in Nepal

Annals of Clinical Chemistry and Laboratory Medicine ◽

10.3126/acclm.v3i2.20737 ◽

2018 ◽

Vol 3 (2) ◽

pp. 1-2

Author(s):

Bishnu Prasad Upadhyay

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Winter Season ◽

Emerging Infectious Diseases ◽

Influenza Viruses ◽

Influenza B ◽

Influenza A Viruses ◽

Influenza A H1n1 ◽

New Variant ◽

Seasonal Epidemics

Influenza virus type A and B are responsible for seasonal epidemics as well as pandemics in human. Influenza A viruses are further divided into two major groups namely, low pathogenic seasonal influenza (A/H1N1, A/H1N1 pdm09, A/H3N2) and highly pathogenic influenza virus (H5N1, H5N6, H7N9) on the basis of two surface antigens: hemagglutinin (HA) and neuraminidase (NA). Mutations, including substitutions, deletions, and insertions, are one of the most important mechanisms for producing new variant of influenza viruses. During the last 30 years; more than 50 viral threat has been evolved in South-East Asian countriesof them influenza is one of the major emerging and re-emerging infectious diseases of global concern. Similar to tropical and sub-tropical countries of Southeast Asia; circulation of A/H1N1 pdm09, A/H3N2 and influenza B has been circulating throughout the year with the peak during July-November in Nepal. However; the rate of infection transmission reach peak during the post-rain and winter season of Nepal.

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Molecular Epidemiology and Antigenic Characterization of Seasonal Influenza Viruses Circulating in Nepal

Journal of Nepal Health Research Council ◽

10.3126/jnhrc.v15i1.18013 ◽

2017 ◽

Vol 15 (1) ◽

pp. 44-50 ◽

Cited By ~ 2

Author(s):

Bishu Prasad Upadhyay ◽

Prakash Ghimire ◽

Masato Tashiro ◽

Mogha Raj Banjara

Keyword(s):

New York ◽

Influenza Virus ◽

Molecular Epidemiology ◽

Influenza A ◽

Influenza Viruses ◽

Influenza B ◽

Antigenic Characterization ◽

Geographical Regions ◽

Influenza A H1n1 ◽

Health Burdens

Background: Influenza is one of the public health burdens in Nepal and its epidemiology is not clearly understood. The objective of this study was to explore the molecular epidemiology and the antigenic characteristics of the circulating influenza viruses in Nepal.Methods: A total of 1495 throat swab specimens were collected from January to December, 2014. Real time PCR assay was used for identification of influenza virus types and subtypes. Ten percent of the positive specimens were randomly selected and inoculated onto Madin-Darby Canine Kidney Epithelial cells (MDCK) for influenza virus isolation. All viruses were characterized by the hemagglutination inhibition (HI) assay.Results: Influenza viruses were detected in 421/1495 (28.2%) specimens. Among positive cases, influenza A virus was detected in 301/421 (71.5%); of which 120 (39.9%) were influenza A/H1N1 pdm09 and 181 (60.1%) were influenza A/H3 subtype. Influenza B viruses were detected in 119/421 (28.3%) specimens. Influenza A/H1N1 pdm09, A/H3 and B viruses isolated in Nepal were antigenically similar to the vaccine strain influenza A/California/07/2009(H1N1pdm09), A/Texas/50/2012(H3N2), A/New York/39/2012(H3N2) and B/Massachusetts/2/2012, respectively.Conclusions: Influenza viruses were reported year-round in different geographical regions of Nepal which was similar to other tropical countries. The circulating influenza virus type and subtypes of Nepal were similar to vaccine candidate virus which could be prevented by currently used influenza vaccine.

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Contemporary Seasonal Influenza A (H1N1) Virus Infection Primes for a More Robust Response To Split Inactivated Pandemic Influenza A (H1N1) Virus Vaccination in Ferrets

Clinical and Vaccine Immunology ◽

10.1128/cvi.00247-10 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1998-2006 ◽

Cited By ~ 11

Author(s):

Ali H. Ellebedy ◽

Thomas P. Fabrizio ◽

Ghazi Kayali ◽

Thomas H. Oguin ◽

Scott A. Brown ◽

...

Keyword(s):

Influenza Virus ◽

Pandemic Influenza ◽

Influenza A ◽

Seasonal Influenza ◽

H1n1 Virus ◽

H1n1 Influenza ◽

Influenza Viruses ◽

Inactivated Vaccine ◽

H1n1 Influenza Virus ◽

Influenza A H1n1

ABSTRACT Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8+ cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.

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Prevalence of Antibodies against Seasonal Influenza A and B Viruses in Children in Netherlands

Clinical and Vaccine Immunology ◽

10.1128/cvi.00396-10 ◽

2011 ◽

Vol 18 (3) ◽

pp. 469-476 ◽

Cited By ~ 112

Author(s):

R. Bodewes ◽

G. de Mutsert ◽

F. R. M. van der Klis ◽

M. Ventresca ◽

S. Wilks ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Influenza Virus Infection ◽

Population Based ◽

Influenza Viruses ◽

Serum Samples ◽

Cross Sectional ◽

Population Based Study ◽

Influenza A H1n1 ◽

First Time

ABSTRACTTo gain insight into the age at which children become infected with influenza viruses for the first time, we analyzed the seroprevalence of antibodies against influenza viruses in children 0 to 7 years of age in the Netherlands. Serum samples were collected during a cross-sectional population-based study in 2006 and 2007 and were tested for the presence of antibodies against influenza A/H1N1, A/H3N2, and B viruses representative of viruses present in previous influenza seasons using the hemagglutination inhibition assay. The seroprevalence of antibodies to influenza virus was higher in children 1 to 6 months of age than in children 7 to 12 months of age, which likely reflects the presence of maternally derived antibodies. The proportion of study subjects >1 year of age with detectable antibodies against influenza viruses gradually increased with age until they reached the age of 6 years, when they all had antibodies to at least one influenza A virus. These findings may have implications for the development of vaccination strategies aiming at the protection of young children against seasonal and/or pandemic influenza virus infection.

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Detecting influenza and emerging avian influenza virus by influenza and pneumonia surveillance systems in a large city in China, 2005 to 2016

10.21203/rs.2.1751/v1 ◽

2019 ◽

Author(s):

Xiaorong Guo ◽

Dong Yang ◽

Ruchun Liu ◽

Yaman Li ◽

Qingqing Hu ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Influenza A ◽

Influenza Viruses ◽

Surveillance Systems ◽

Avian Influenza Viruses ◽

Influenza A H1n1 ◽

Death Cases ◽

Positive Results

Abstract Background: Detecting avian influenza virus has become an important public health strategy for controlling the emerging infectious disease. This study aimed to analyze the efficiency of two surveillance systems in detecting the emerging avian influenza viruses. Methods: A modified influenza surveillance system (ISS) and a new built pneumonia surveillance system (PSS) have been used to monitor the viruses in Changsha City, China. The ISS is based on monitoring outpatients in two sentinel hospitals to detect mild influenza and avian influenza cases, and PSS is based on monitoring inpatients in all 49 hospitals to detect severe and death influenza cases. Results: During the study period, 3551917 outpatients were monitored by the ISS system, among which 126076 were influenza-like illness (ILI) cases, with the ILI% of 3.55%. Totally, 14913 throat swabs were collected by the ISS system, among which 2016 were tested positive of influenza or avian influenza virus. Among the positive results, 621 were H3N2, 135 were seasonal H1N1, 610 were influenza A/H1N1 (pandemic in 2009), 106 were untyped influenza A, 540 were B, 1 was H5N6, 1 was H7N9, and 2 were H9N2 virus. 5491560 inpatient people were monitored by the PSS system, among which 6.61% (362743/5491560) were pneumonia cases. 10.55% (38260/362743) of reported pneumonia was severe or death cases. 3401 throat swab or lower respiratory tract samples were collected, among which 2094 were tested positive of influenza or avian influenza virus. Among the positive results, 78 were H3N2, 17 were seasonal H1N1, 1871 were influenza A/H1N1, 103 were untyped influenza A, 16 were B, 1 was H5N6, and 8 were H7N9 virus. Of 15 avian influenza cases reported from January, 2005 to September, 2016, 26.7% (4/15) were mild cases detected by the ISS system, while 60.0% (9/15) were severe or death cases detected by the PSS system. Two H5N1 severe cases were missed by the ISS system in January, 2009 when the PSS system was not available. Conclusion: The two systems seem to be of high efficiency in detecting the emerging avian influenza viruses but need to be verified in other cities or countries.

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Pharmacokinetic and pharmacodynamic analysis of baloxavir marboxil, a novel cap-dependent endonuclease inhibitor, in a murine model of influenza virus infection

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa393 ◽

2020 ◽

Vol 76 (1) ◽

pp. 189-198

Author(s):

Yoshinori Ando ◽

Takeshi Noshi ◽

Kenji Sato ◽

Toru Ishibashi ◽

Yuki Yoshida ◽

...

Keyword(s):

Influenza Virus ◽

Plasma Concentration ◽

Influenza A ◽

Lethal Dose ◽

Influenza Viruses ◽

Virus Titre ◽

Dependent Endonuclease ◽

Influenza A H1n1 ◽

B Virus ◽

Oseltamivir Phosphate

Abstract Background Baloxavir acid, the active form of the orally available prodrug baloxavir marboxil, is a novel cap-dependent endonuclease inhibitor of influenza virus. Baloxavir marboxil has been shown to rapidly reduce virus titres compared with oseltamivir in clinical studies. Objectives We investigated the relationship between pharmacokinetic (PK) parameters and antiviral activity of baloxavir acid based on virus titre reduction in lungs of infected mice. Methods BALB/c mice infected with a sub-lethal dose of influenza A(H1N1), A(H1N1)pdm09, A(H3N2) or type B virus were treated on day 5 with oral baloxavir marboxil (0.5–50 mg/kg q12h), subcutaneous baloxavir acid (0.25–8 mg/kg/day), oseltamivir phosphate (5 or 50 eq mg/kg q12h) or other antivirals for 1 day. Lung virus titres were assessed 24 h after initial antiviral dosing. PK testing was performed at up to 24 h post-dosing of baloxavir marboxil or baloxavir acid in A/WSN/33-infected mice and the PK/pharmacodynamic (PD) relationship was evaluated for baloxavir acid. Results Oral baloxavir marboxil administration showed dose-dependent virus titre reductions in lungs of mice infected with the different types/subtypes of influenza viruses 24 h post-dosing. Baloxavir marboxil at 15 mg/kg q12h resulted in ≥100-fold and ≥10-fold reductions in influenza A and B virus titres, respectively, compared with oseltamivir phosphate. PK/PD analysis showed that the plasma concentration at the end of the dosing interval (Cτ) or the plasma concentration at 24 h after initial dosing (C24) was the PK parameter predicting the virus titres at 24 h post-dosing of baloxavir acid. Conclusions PK/PD analysis of baloxavir acid based on virus titre reduction in this mouse model could be helpful in predicting and maximizing virological outcomes in clinical settings.

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Influenza A virus transmission: contributing factors and clinical implications

Expert Reviews in Molecular Medicine ◽

10.1017/s1462399410001705 ◽

2010 ◽

Vol 12 ◽

Cited By ~ 43

Author(s):

Jessica A. Belser ◽

Taronna R. Maines ◽

Terrence M. Tumpey ◽

Jacqueline M. Katz

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Influenza A ◽

Severe Disease ◽

Virus Transmission ◽

Influenza Viruses ◽

Clinical Implications ◽

Influenza A Viruses ◽

Molecular Features ◽

Efficient Transmission

Efficient human-to-human transmission is a necessary property for the generation of a pandemic influenza virus. To date, only influenza A viruses within the H1–H3 subtypes have achieved this capacity. However, sporadic cases of severe disease in individuals following infection with avian influenza A viruses over the past decade, and the emergence of a pandemic H1N1 swine-origin virus in 2009, underscore the need to better understand how influenza viruses acquire the ability to transmit efficiently. In this review, we discuss the biological constraints and molecular features known to affect virus transmissibility to and among humans. Factors influencing the behaviour of aerosols in the environment are described, and the mammalian models used to study virus transmission are presented. Recent progress in understanding the molecular determinants that confer efficient transmission has identified crucial roles for the haemagglutinin and polymerase proteins; nevertheless, influenza virus transmission remains a polygenic trait that is not completely understood. The clinical implications of this research, including methods currently under investigation to mitigate influenza virus human-to-human transmission, are discussed. A better understanding of the viral determinants necessary for efficient transmission will allow us to identify avian influenza viruses with pandemic potential.

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KONFIRMASI FLU BABI A/H1N1 MENGGUNAKAN PCR

INDONESIAN JOURNAL OF CLINICAL PATHOLOGY AND MEDICAL LABORATORY ◽

10.24293/ijcpml.v16i2.979 ◽

2018 ◽

Vol 16 (2) ◽

pp. 93

Author(s):

A.A. Wiradewi Lestari ◽

I.A. Putri Wirawati ◽

Tjok Gde Oka

Keyword(s):

Influenza Virus ◽

Sore Throat ◽

Influenza A ◽

Swine Influenza ◽

Influenza Viruses ◽

Influenza A H1n1 ◽

Nasal Swabs ◽

2009 H1n1 ◽

Pcr Test

Swine Influenza (2009 H1N1) is a new influenza virus causing illness in people. This new virus was first detected in the United Statespeople, April 2009. This virus probably spread the same way worldwide from person-to-person much as the regular spreading of commonseasonal influenza viruses. A 13 years old male entered the hospital with fever, cough and sore throat. Before he was hospitalized, hehad travelled to Batam for four (4) days. A PCR test from throat and nasal swabs were taken, and found positive for influenza A andswine H1 (as confirmed case for swine influenza A/H1N1). After taking oseltamivir for 5 days and the second PCR test negative, thepatient is released from the hospital.

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Enhanced surveillance of influenza A(H1N1)v in Greece during the containment phase

Eurosurveillance ◽

10.2807/ese.14.29.19275-en ◽

2009 ◽

Vol 14 (29) ◽

Cited By ~ 9

Author(s):

T Lytras ◽

G Theocharopoulos ◽

S Tsiodras ◽

A Mentis ◽

T Panagiotopoulos ◽

...

Keyword(s):

Public Health ◽

Influenza Virus ◽

Influenza A ◽

Disease Spread ◽

Public Health Action ◽

Health Measures ◽

Influenza A H1n1 ◽

Health Action ◽

Virus Influenza

Following the emergence of a novel influenza virus (influenza A(H1N1)v) with pandemic potential in late April 2009, public health measures were put in place in an effort to contain disease spread in Greece. These included enhanced surveillance of infections due to influenza A(H1N1)v virus, in order to continuously ascertain the situation and guide further public health action. On 15 July, Greece moved to mitigation phase. This report summarises surveillance findings in Greece during the delaying (or “containment”) phase, from 30 April to 14 July 2009.

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