How long does the flu typically last. What are the key factors influencing flu duration. When are you most contagious with the flu. How can you prevent spreading the flu to others. What are the recommended treatments for influenza. How does flu virus diversity impact transmission and prevention strategies. What role does influenza play in the epidemiology of pneumonia.

The Nature and Duration of Influenza Type A

Influenza, commonly known as the flu, is a highly contagious respiratory illness caused by influenza viruses. Type A influenza is one of the most prevalent strains, known for its ability to cause seasonal epidemics and occasional pandemics. But how long does this viral infection typically last?

The duration of flu type A can vary from person to person, but generally, symptoms persist for about 5 to 7 days in healthy adults. However, some individuals may experience symptoms for up to two weeks. Factors influencing the duration include the patient’s age, overall health, and immune system strength.

Stages of Flu Progression

• Incubation period: 1-4 days
• Onset of symptoms: Sudden and severe
• Peak symptoms: Days 2-4
• Gradual improvement: Days 5-7
• Full recovery: 1-2 weeks

Can certain populations experience longer flu durations? Yes, children, elderly individuals, and those with compromised immune systems may have prolonged symptoms and recovery periods, sometimes lasting several weeks.

Contagiousness and Transmission of Influenza A

Understanding the contagious period of influenza is crucial for preventing its spread. Typically, individuals with flu type A are contagious from 1 day before symptoms appear until 5 to 7 days after onset. This means you can unknowingly spread the virus before realizing you’re sick.

How does the flu virus spread so effectively? The primary mode of transmission is through respiratory droplets expelled when an infected person coughs, sneezes, or talks. These droplets can travel up to 6 feet and can be inhaled by others or land on surfaces, where the virus can survive for up to 48 hours.

Peak Contagiousness

When are you most likely to spread the flu? Research suggests that the first 3 to 4 days of illness are when you’re most contagious. During this period, viral shedding is at its highest, and symptoms like coughing and sneezing are most frequent, increasing the likelihood of transmitting the virus to others.

Recognizing and Managing Flu Symptoms

Identifying flu symptoms early can help in managing the illness and reducing transmission. Common symptoms of influenza A include:

• Sudden onset of fever
• Body aches and fatigue
• Dry cough
• Sore throat
• Runny or stuffy nose
• Headache
• Chills

Is there a way to differentiate between flu and other respiratory infections? While some symptoms overlap with common colds, the flu typically comes on more suddenly and severely. Fever is a key indicator, often absent in colds but common in flu cases.

Antiviral Medications and Their Impact on Flu Duration

Antiviral medications play a significant role in managing influenza A infections. The CDC recommends four FDA-approved drugs: baloxavir marboxil (Xofluza), oseltamivir (Tamiflu), peramivir (Rapivab), and zanamivir (Relenza). These medications can shorten the duration of illness and potentially reduce the contagious period.

Do antiviral drugs completely stop the spread of flu? No, while these medications can help reduce symptoms and shorten the illness duration, they do not entirely prevent transmission. Patients taking antivirals can still spread the virus, albeit potentially for a shorter period.

Effectiveness of Antiviral Treatments

The efficacy of antiviral treatments depends on various factors, including:

• Timing of administration (ideally within 48 hours of symptom onset)
• The specific strain of influenza
• Patient’s overall health and immune status
• Adherence to prescribed dosage and duration

Prevention Strategies and Vaccine Importance

Prevention remains the most effective strategy against influenza A. Annual vaccination is the cornerstone of flu prevention, offering protection against the most prevalent strains predicted for each season. But how effective are flu vaccines?

Flu vaccine effectiveness varies from year to year, typically ranging from 40% to 60% when well-matched to circulating strains. Even when not perfectly matched, vaccines can reduce the severity of illness and risk of complications.

Additional Prevention Measures

1. Regular hand washing
2. Avoiding close contact with infected individuals
3. Covering mouth and nose when coughing or sneezing
4. Staying home when sick
5. Maintaining a healthy lifestyle to support immune function

The Role of Influenza in Pneumonia Epidemiology

Influenza plays a significant role in the epidemiology of pneumonia, often serving as a precursor to more severe respiratory infections. How does flu increase pneumonia risk? The influenza virus can damage the respiratory tract, making it more susceptible to bacterial infections that cause pneumonia.

A study by Shrestha et al. (2015) highlighted the intricate relationship between influenza and pneumonia, demonstrating that influenza infections often precede spikes in pneumonia cases. This connection underscores the importance of flu prevention in reducing overall respiratory disease burden.

Global Impact and Pandemic Potential of Influenza A

Influenza A’s ability to undergo rapid genetic changes makes it a constant global health concern. The virus’s capacity for antigenic drift (minor changes) and shift (major changes) can lead to the emergence of novel strains with pandemic potential.

How often do influenza pandemics occur? While not predictable, influenza pandemics have occurred roughly three to four times per century. The most notable in recent history was the 2009 H1N1 “swine flu” pandemic, which highlighted the need for global preparedness and rapid response strategies.

Historical Perspective on Influenza Pandemics

• 1918 Spanish Flu: Estimated 50 million deaths worldwide
• 1957 Asian Flu: About 1.1 million deaths globally
• 1968 Hong Kong Flu: Approximately 1 million deaths
• 2009 H1N1 Swine Flu: Between 151,700 and 575,400 deaths worldwide

Advances in Influenza Research and Future Directions

Ongoing research in influenza virology and epidemiology continues to shape our understanding and management of the disease. Recent studies have focused on quantifying influenza virus diversity and transmission patterns in humans, as highlighted by Poon et al. (2016).

What are the key areas of current influenza research? Scientists are exploring universal vaccine development, improved antiviral treatments, and enhanced surveillance methods to predict and prevent future pandemics. The goal is to create more effective, long-lasting protection against a broader range of influenza strains.

Emerging Technologies in Flu Research

• Next-generation sequencing for rapid virus characterization
• Big data analytics for predicting flu outbreaks
• CRISPR gene-editing techniques for studying virus-host interactions
• AI-driven drug discovery for new antiviral compounds

As our understanding of influenza A continues to evolve, so do our strategies for prevention, treatment, and control. The dynamic nature of the virus necessitates ongoing vigilance and adaptation in public health approaches. By staying informed about the latest developments in flu research and adhering to recommended prevention measures, individuals can play a crucial role in mitigating the impact of seasonal and pandemic influenza.

The global effort to combat influenza remains a testament to the power of scientific collaboration and public health initiatives. As we face future challenges posed by this ever-changing virus, the lessons learned from past epidemics and the insights gained from cutting-edge research will be invaluable in shaping our response and protecting global health.

How Long Are You Contagious?

Written by WebMD Editorial Contributors

Doctors tell you to stay home when you have the flu so you don’t get other people sick. But how long do you have to shut yourself away? Here’s how to know when you can be out and about again.

How long can I spread it?

About a week. Typically, you’re contagious from 1 day before you have any symptoms. You stay that way for 5 to 7 days after you start feeling sick. Kids and people with weak immune systems may shed the virus even longer. The virus can be spread until symptoms disappear.

How do I spread it?

Most of the time, it’s through droplets in the air. Sick people sneeze or cough out beads of moisture that contain the flu virus. They can travel up to 6 feet. You’re exposed to the flu virus when you breathe the droplets in, or if they land in your mouth, nose, or eyes. You can also get it if you touch a place those droplets land — like a desk, counter, or doorknob — and then touch your face. The virus can live on hard surfaces for up to 48 hours.

When am I most contagious?

Some experts believe you’re most likely to spread the virus in the first 3 to 4 days. That’s because the more you cough and sneeze, the more droplets you shoot into the air and onto objects around you.

Is there a way to tell if I’m still contagious?

Fever is a definite sign. You should stay home for at least 24 hours after your temperature goes back down on its own. That means without the help of medicines.

Do flu medicines help stop the spread?

No. You can still make other people sick even if you’re taking antiviral mediations that treat the flu. The CDC recommends four FDA-approved drugs to treat the flu: baloxavir marboxil (Xofluza), oseltamivir (Tamiflu), peramivir (Rapivab), and zanamivir (Relenza). These drugs could shorten the time that you’re sick. And they might shorten the length of time that you can spread the flu.

The Bottom Line:

When it comes to the flu, an ounce of prevention really is worth a pound of cure. Listen to your doctor: Stay away from people when you’re sick, even if you start to feel better. It’s the only way not to spread the flu. And remember you and your family should get the annual flu vaccine.

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1. Shrestha S, Foxman B, Berus J, van Panhuis W, Steiner C, Viboud C, et al. The role of influenza in the epidemiology of pneumonia. Sci Rep. 2015;5:15314. doi: 10.1038/srep15314. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

2. Heesterbeek H, Anderson RM, Andreasen V, Bansal S, De Angelis D, Dye C, et al. Modeling infectious disease dynamics in the complex landscape of global health. Science. 2015;347:aaa4339. doi: 10.1126/science.aaa4339. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

3. Hirsch A. Handbook of geographical and historical pathology. London: New Sydenham Society; 1883. [Google Scholar]

4. Molineux D. Dr. Molineux’s Historical Account of the Late General Coughs and Colds;with Some Observations on Other Epidemick Distempers. Philosophical Transactions. 1683-1775;1694:105–11. [Google Scholar]

5. Johnson NP, Mueller J. Updating the accounts: global mortality of the 1918-1920 “Spanish” influenza pandemic. Bull Hist Med. 2002;76:105–15. [PubMed] [Google Scholar]

6. Novel Swine-Origin Influenza AVIT. Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, et al. Emergence of a novel swine-origin influenza A (h2N1) virus in humans. N Engl J Med. 2009;360:2605–15. doi: 10.1056/NEJMoa0903810. [PubMed] [CrossRef] [Google Scholar]

7. Influenza WP. Report of the WHO pandemic influenza A (h2N1) vaccine deployment initiative. 2012 [Google Scholar]

8. Mosnier A, Caini S, Daviaud I, Nauleau E, Bui TT, Debost E, et al. Clinical Characteristics Are Similar across Type A and B Influenza Virus Infections. PLoS One. 2015;10:e0136186. doi: 10.1371/journal.pone.0136186. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

9. Poon LL, Song T, Rosenfeld R, Lin X, Rogers MB, Zhou B, et al. Quantifying influenza virus diversity and transmission in humans. Nat Genet. 2016;48:195–200. doi: 10.1038/ng.3479. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

10. Fuller TL, Gilbert M, Martin V, Cappelle J, Hosseini P, Njabo KY, et al. Predicting hotspots for influenza virus reassortment. Emerg Infect Dis. 2013;19:581–8. doi: 10.3201/eid1904.120903. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

11. Kanegae Y, Sugita S, Endo A, Ishida M, Senya S, Osako K, et al. Evolutionary pattern of the hemagglutinin gene of influenza B viruses isolated in Japan: cocirculating lineages in the same epidemic season. J Virol. 1990;64:2860–5. [ PMC Free Article] [PMC free article] [PubMed] [Google Scholar]

12. Moghadami M, Moattari A, Tabatabaee HR, Mirahmadizadeh A, Rezaianzadeh A, Hasanzadeh J, et al. High titers of hemagglutination inhibition antibodies against 2009 h2N1 influenza virus in Southern Iran. Iran J Immunol. 2010;7:39–48. [PubMed] [Google Scholar]

13. Webster RG, Kendal AP, Gerhard W. Analysis of antigenic drift in recently isolated influenza A (h2N1) viruses using monoclonal antibody preparations. Virology. 1979;96:258–64. [PubMed] [Google Scholar]

14. Siston AM, Rasmussen SA, Honein MA, Fry AM, Seib K, Callaghan WM, et al. Pandemic 2009 influenza A(h2N1) virus illness among pregnant women in the United States. JAMA. 2010;303:1517–25. doi: 10.1001/jama.2010.479. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

15. Freeman DW, Barno A. Deaths from Asian influenza associated with pregnancy. Am J Obstet Gynecol. 1959;78:1172–5. [PubMed] [Google Scholar]

16. Bhat N, Wright JG, Broder KR, Murray EL, Greenberg ME, Glover MJ, et al. Influenza-associated deaths among children in the United States 2003-2004. N Engl J Med. 2005;353:2559–67. doi: 10.1056/NEJMoa051721. [PubMed] [CrossRef] [Google Scholar]

17. Brankston G, Gitterman L, Hirji Z, Lemieux C, Gardam M. Transmission of influenza A in human beings. Lancet Infect Dis. 2007;7:257–65. doi: 10.1016/S1473-3099(07)70029-4. [PubMed] [CrossRef] [Google Scholar]

18. Fiore AE, Fry A, Shay D, Gubareva L, Bresee JS, Uyeki TM, et al. Antiviral agents for the treatment and chemoprophylaxis of influenza — recommendations of the Advisory Committee on Immunization Practices (ACIP) MMWR Recomm Rep. 2011;60:1–24. [PubMed] [Google Scholar]

19. Cowling BJ, Ip DK, Fang VJ, Suntarattiwong P, Olsen SJ, Levy J, et al. Aerosol transmission is an important mode of influenza A virus spread. Nat Commun. 2013;4:1935. doi: 10.1038/ncomms2922. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

20. Wong BC, Lee N, Li Y, Chan PK, Qiu H, Luo Z, et al. Possible role of aerosol transmission in a hospital outbreak of influenza. Clin Infect Dis. 2010;51:1176–83. doi: 10.1086/656743. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

21. Carrat F, Vergu E, Ferguson NM, Lemaitre M, Cauchemez S, Leach S, et al. Time lines of infection and disease in human influenza: a review of volunteer challenge studies. Am J Epidemiol. 2008;167:775–85. doi: 10.1093/aje/kwm375. [PubMed] [CrossRef] [Google Scholar]

22. Boivin G, Goyette N, Bernatchez H. Prolonged excretion of amantadine-resistant influenza a virus quasi species after cessation of antiviral therapy in an immunocompromised patient. Clin Infect Dis. 2002;34:E23–5. doi: 10.1086/338870. [PubMed] [CrossRef] [Google Scholar]

23. Weinstock DM, Gubareva LV, Zuccotti G. Prolonged shedding of multidrug-resistant influenza A virus in an immunocompromised patient. N Engl J Med. 2003;348:867–8. doi: 10.1056/NEJM200302273480923. [PubMed] [CrossRef] [Google Scholar]

24. Liu W, Peng L, Liu H, Hua S. Pulmonary Function and Clinical Manifestations of Patients Infected with Mild Influenza A Virus Subtype h2N1: A One-Year Follow-Up. PLoS One. 2015;10:e0133698. doi: 10.1371/journal.pone.0133698. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

25. Rello J, Pop-Vicas A. Clinical review: primary influenza viral pneumonia. Crit Care. 2009;13:235. doi: 10.1186/cc8183. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

26. Minodier L, Charrel RN, Ceccaldi PE, van der Werf S, Blanchon T, Hanslik T, et al. Prevalence of gastrointestinal symptoms in patients with influenza, clinical significance, and pathophysiology of human influenza viruses in faecal samples: what do we know? Virol J. 2015;12:215. doi: 10.1186/s12985-015-0448-4. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

27. Kloth C, Forler S, Gatidis S, Beck R, Spira D, Nikolaou K, et al. Comparison of chest-CT findings of Influenza virus-associated pneumonia in immunocompetent vs. immunocompromised patients. Eur J Radiol. 2015;84:1177–83. doi: 10.1016/j.ejrad.2015.02.014. [PubMed] [CrossRef] [Google Scholar]

28. Mancinelli L, Onori M, Concato C, Sorge R, Chiavelli S, Coltella L, et al. Clinical features of children hospitalized with influenza A and B infections during the 2012-2013 influenza season in Italy. BMC Infect Dis. 2016;16:6. doi: 10.1186/s12879-015-1333-x. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

29. Rello J, Rodriguez A, Ibanez P, Socias L, Cebrian J, Marques A, et al. Intensive care adult patients with severe respiratory failure caused by Influenza A (h2N1)v in Spain. Crit Care. 2009;13:R148. doi: 10.1186/cc8044. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

30. To KK, Hung IF, Li IW, Lee KL, Koo CK, Yan WW, et al. Delayed clearance of viral load and marked cytokine activation in severe cases of pandemic h2N1 2009 influenza virus infection. Clin Infect Dis. 2010;50:850–9. doi: 10.1086/650581. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

31. Schwarzmann SW, Adler JL, Sullivan RJ, Jr, Marine WM. Bacterial pneumonia during the Hong Kong influenza epidemic of 1968-1969. Arch Intern Med. 1971;127:1037–41. [PubMed] [Google Scholar]

32. Kallen AJ, Brunkard J, Moore Z, Budge P, Arnold KE, Fosheim G, et al. Staphylococcus aureus community-acquired pneumonia during the 2006 to 2007 influenza season. Ann Emerg Med. 2009;53:358–65. doi: 10. 1016/j.annemergmed.2008.04.027. [PubMed] [CrossRef] [Google Scholar]

33. Ison MG, Campbell V, Rembold C, Dent J, Hayden FG. Cardiac findings during uncomplicated acute influenza in ambulatory adults. Clin Infect Dis. 2005;40:415–22. doi: 10.1086/427282. [PubMed] [CrossRef] [Google Scholar]

34. Foulkes W, Rees J, Sewry C. Influenza A and rhabdomyolysis. J Infect. 1990;21:303–4. [PubMed] [Google Scholar]

35. Chen KF, Gaydos C, Rothman RE. Update on emerging infections: news from the Centers for Disease Control and Prevention Hospitalized patients with novel influenza A (h2N1) virus infection–California, April-May 2009. Ann Emerg Med. 2009;54:732–6. [PMC free article] [PubMed] [Google Scholar]

36. Kaufman MA, Duke GJ, McGain F, French C, Aboltins C, Lane G, et al. Life-threatening respiratory failure from h2N1 influenza 09 (human swine influenza) Med J Aust. 2009;191:154–6. [PubMed] [Google Scholar]

37. Chu H, Lofgren ET, Halloran ME, Kuan PF, Hudgens M, Cole SR. Performance of rapid influenza h2N1 diagnostic tests: a meta-analysis. Influenza Other Respir Viruses. 2012;6:80–6. doi: 10.1111/j.1750-2659.2011.00284.x. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

38. Chartrand C, Leeflang MM, Minion J, Brewer T, Pai M. Accuracy of rapid influenza diagnostic tests: a meta-analysis. Ann Intern Med. 2012;156:500–11. doi: 10.7326/0003-4819-156-7-201204030-00403. [PubMed] [CrossRef] [Google Scholar]

39. Lee BY, McGlone SM, Bailey RR, Wiringa AE, Zimmer SM, Smith KJ, et al. To test or to treat?An analysis of influenza testing and antiviral treatment strategies using economic computer modeling. PLoS One. 2010;5:e11284. doi: 10.1371/journal.pone.0011284. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

40. Nagase H, Moriwaki K, Kamae M, Yanagisawa S, Kamae I. Cost-effectiveness analysis of oseltamivir for influenza treatment considering the virus emerging resistant to the drug in Japan. Value Health. 2009;12(Suppl 3):S62–5. doi: 10.1111/j.1524-4733.2009.00629.x. [PubMed] [CrossRef] [Google Scholar]

41. Nshimyumukiza L, Douville X, Fournier D, Duplantie J, Daher RK, Charlebois I, et al. Cost-effectiveness analysis of antiviral treatment in the management of seasonal influenza A: point-of-care rapid test versus clinical judgment. Influenza Other Respir Viruses. 2016;10:113–21. doi: 10.1111/irv.12359. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

42. Kumar S, Henrickson KJ. Update on influenza diagnostics: lessons from the novel h2N1 influenza A pandemic. Clin Microbiol Rev. 2012;25:344–61. doi: 10.1128/CMR.05016-11. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

43. Teo J, Di Pietro P, San Biagio F, Capozzoli M, Deng YM, Barr I, et al. VereFlu: an integrated multiplex RT-PCR and microarray assay for rapid detection and identification of human influenza A and B viruses using lab-on-chip technology. Arch Virol. 2011;156:1371–8. doi: 10.1007/s00705-011-0999-7. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

44. Tang YW, Lowery KS, Valsamakis A, Schaefer VC, Chappell JD, White-Abell J, et al. Clinical accuracy of a PLEX-ID flu device for simultaneous detection and identification of influenza viruses A and B. J Clin Microbiol. 2013;51:40–5. doi: 10.1128/JCM.01978-12. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

45. Loeffelholz MJ, Pong DL, Pyles RB, Xiong Y, Miller AL, Bufton KK, et al. Comparison of the FilmArray Respiratory Panel and Prodesse real-time PCR assays for detection of respiratory pathogens. J Clin Microbiol. 2011;49:4083–8. doi: 10.1128/JCM.05010-11. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

46. Harper SA, Bradley JS, Englund JA, File TM, Gravenstein S, Hayden FG, et al. Seasonal influenza in adults and children–diagnosis, treatment, chemoprophylaxis, and institutional outbreak management: clinical practice guidelines of the Infectious Diseases Society of America. Clin Infect Dis. 2009;48:1003–32. doi: 10.1086/598513. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

47. Muthuri SG, Venkatesan S, Myles PR, Leonardi-Bee J, Al Khuwaitir TS, Al Mamun A, et al. Effectiveness of neuraminidase inhibitors in reducing mortality in patients admitted to hospital with influenza A h2N1pdm09 virus infection: a meta-analysis of individual participant data. Lancet Respir Med. 2014;2:395–404. doi: 10.1016/S2213-2600(14)70041-4. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

48. Gasparini R, Amicizia D, Lai PL, Bragazzi NL, Panatto D. Compounds with anti-influenza activity: present and future of strategies for the optimal treatment and management of influenza. Part I: Influenza life-cycle and currently available drugs. J Prev Med Hyg. 2014;55:69–85. [ PMC Free Article] [PMC free article] [PubMed] [Google Scholar]

49. World Health Organization (WHO) [Internet] Clinical management of human infection with pandemic (h2N1) 2009. [Revised guidance [cited 2014 November 18]]. Available from: http://www.who.int/csr/resources/publications/swineflu/clinical_management_h2n1.pdf .

50. Kaiser L, Wat C, Mills T, Mahoney P, Ward P, Hayden F. Impact of oseltamivir treatment on influenza-related lower respiratory tract complications and hospitalizations. Arch Intern Med. 2003;163:1667–72. doi: 10.1001/archinte.163.14.1667. [PubMed] [CrossRef] [Google Scholar]

51. Hsu J, Santesso N, Mustafa R, Brozek J, Chen YL, Hopkins JP, et al. Antivirals for treatment of influenza: a systematic review and meta-analysis of observational studies. Ann Intern Med. 2012;156:512–24. doi: 10.7326/0003-4819-156-7-201204030-00411. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

52. Doshi P, Jefferson T, Del Mar C. The imperative to share clinical study reports: recommendations from the Tamiflu experience. PLoS Med. 2012;9:e1001201. doi: 10.1371/journal.pmed.1001201. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

53. Muthuri SG, Venkatesan S, Myles PR, Leonardi-Bee J, Lim WS, Al Mamun A, et al. Impact of neuraminidase inhibitors on influenza A(h2N1)pdm09-related pneumonia: an individual participant data meta-analysis. Influenza Other Respir Viruses. 2016;10:192–204. doi: 10.1111/irv.12363. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

54. Chen LF, Dailey NJ, Rao AK, Fleischauer AT, Greenwald I, Deyde VM, et al. Cluster of oseltamivir-resistant 2009 pandemic influenza A (h2N1) virus infections on a hospital ward among immunocompromised patients–North Carolina 2009. J Infect Dis. 2011;203:838–46. doi: 10.1093/infdis/jiq124. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

55. Stephenson I, Democratis J, Lackenby A, McNally T, Smith J, Pareek M, et al. Neuraminidase inhibitor resistance after oseltamivir treatment of acute influenza A and B in children. Clin Infect Dis. 2009;48:389–96. doi: 10.1086/596311. [PubMed] [CrossRef] [Google Scholar]

56. Ramos EL, Mitcham JL, Koller TD, Bonavia A, Usner DW, Balaratnam G, et al. Efficacy and safety of treatment with an anti-m2e monoclonal antibody in experimental human influenza. J Infect Dis. 2015;211:1038–44. doi: 10.1093/infdis/jiu539. [PubMed] [CrossRef] [Google Scholar]

57. Schotsaert M, De Filette M, Fiers W, Saelens X. Universal M2 ectodomain-based influenza A vaccines: preclinical and clinical developments. Expert Rev Vaccines. 2009;8:499–508. doi: 10.1586/erv.09.6. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

58. Jegerlehner A, Schmitz N, Storni T, Bachmann MF. Influenza A vaccine based on the extracellular domain of M2: weak protection mediated via antibody-dependent NK cell activity. J Immunol. 2004;172:5598–605. [PubMed] [Google Scholar]

59. Mair-Jenkins J, Saavedra-Campos M, Baillie JK, Cleary P, Khaw FM, Lim WS, et al. The effectiveness of convalescent plasma and hyperimmune immunoglobulin for the treatment of severe acute respiratory infections of viral etiology: a systematic review and exploratory meta-analysis. J Infect Dis. 2015;211:80–90. doi: 10.1093/infdis/jiu396. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

60. Diaz E, Martin-Loeches I, Canadell L, Vidaur L, Suarez D, Socias L, et al. Corticosteroid therapy in patients with primary viral pneumonia due to pandemic (h2N1) 2009 influenza. J Infect. 2012;64:311–8. doi: 10.1016/j.jinf.2011.12.010. [PubMed] [CrossRef] [Google Scholar]

61. Brun-Buisson C, Richard JC, Mercat A, Thiebaut AC, Brochard L, Group R-SAHNvR Early corticosteroids in severe influenza A/h2N1 pneumonia and acute respiratory distress syndrome. Am J Respir Crit Care Med. 2011;183:1200–6. doi: 10.1164/rccm.201101-0135OC. [PubMed] [CrossRef] [Google Scholar]

62. Linko R, Pettila V, Ruokonen E, Varpula T, Karlsson S, Tenhunen J, et al. Corticosteroid therapy in intensive care unit patients with PCR-confirmed influenza A(h2N1) infection in Finland. Acta Anaesthesiol Scand. 2011;55:971–9. doi: 10.1111/j.1399-6576.2011.02491.x. [PubMed] [CrossRef] [Google Scholar]

63. Rodrigo C, Leonardi-Bee J, Nguyen-Van-Tam JS, Lim WS. Effect of corticosteroid therapy on influenza-related mortality: a systematic review and meta-analysis. J Infect Dis. 2015;212:183–94. doi: 10.1093/infdis/jiu645. [PubMed] [CrossRef] [Google Scholar]

64. Kilbourne ED. Influenza immunity: new insights from old studies. J Infect Dis. 2006;193:7–8. doi: 10.1086/498984. [PubMed] [CrossRef] [Google Scholar]

65. Glezen WP. Clinical practice. Prevention and treatment of seasonal influenza. N Engl J Med. 2008;359:2579–85. doi: 10.1056/NEJMcp0807498. [PubMed] [CrossRef] [Google Scholar]

66. Ang LW, Tien WS, Lin RT, Cui L, Cutter J, James L, et al. Characterization of influenza activity based on virological surveillance of influenza-like illness in tropical Singapore 2010-2014. J Med Virol. 2016;88:2069–77. doi: 10.1002/jmv.24566. [PubMed] [CrossRef] [Google Scholar]

67. Zhao B, Qin S, Teng Z, Chen J, Yu X, Gao Y, et al. Epidemiological study of influenza B in Shanghai during the 2009-2014 seasons: implications for influenza vaccination strategy. Clin Microbiol Infect. 2015;21:694–700. doi: 10.1016/j.cmi.2015.03.009. [PubMed] [CrossRef] [Google Scholar]

68. Meerhoff TJ, Simaku A, Ulqinaku D, Torosyan L, Gribkova N, Shimanovich V, et al. Surveillance for severe acute respiratory infections (SARI) in hospitals in the WHO European region – an exploratory analysis of risk factors for a severe outcome in influenza-positive SARI cases. BMC Infect Dis. 2015;15:1. doi: 10.1186/s12879-014-0722-x. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

69. Grohskopf LA, Sokolow LZ, Olsen SJ, Bresee JS, Broder KR, Karron RA. Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States 2015-16 Influenza Season. MMWR Morb Mortal Wkly Rep. 2015;64:818–25. [PMC free article] [PubMed] [Google Scholar]

70. Ohmit SE, Petrie JG, Malosh RE, Fry AM, Thompson MG, Monto AS. Influenza vaccine effectiveness in households with children during the 2012-2013 season: assessments of prior vaccination and serologic susceptibility. J Infect Dis. 2015;211:1519–28. doi: 10.1093/infdis/jiu650. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

71. Flannery B, Clippard J, Zimmerman RK, Nowalk MP, Jackson ML, Jackson LA, et al. Early estimates of seasonal influenza vaccine effectiveness – United States, January 2015. MMWR Morb Mortal Wkly Rep. 2015;64:10–5. [PMC free article] [PubMed] [Google Scholar]

72. Ampofo WK, Azziz-Baumgartner E, Bashir U, Cox NJ, Fasce R, Giovanni M, et al. Strengthening the influenza vaccine virus selection and development process: Report of the 3rd WHO Informal Consultation for Improving Influenza Vaccine Virus Selection held at WHO headquarters, Geneva, Switzerland, 1-3 April 2014. Vaccine. 2015;33:4368–82. doi: 10.1016/j.vaccine.2015.06.090. [PubMed] [CrossRef] [Google Scholar]

73. Li TC, Chan MC, Lee N. Clinical Implications of Antiviral Resistance in Influenza. Viruses. 2015;7:4929–44. doi: 10.3390/v7092850. [ PMC Free Article] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

74. Merritt T, Hope K, Butler M, Durrheim D, Gupta L, Najjar Z, et al. Effect of antiviral prophylaxis on influenza outbreaks in aged care facilities in three local health districts in New South Wales, Australia 2014. Western Pac Surveill Response J. 2016;7:14–20. doi: 10.5365/WPSAR.2015.6.3.005. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

75. Louie JK, Salibay CJ, Kang M, Glenn-Finer RE, Murray EL, Jamieson DJ. Pregnancy and severe influenza infection in the 2013-2014 influenza season. Obstet Gynecol. 2015;125:184–92. doi: 10.1097/AOG.0000000000000593. [PubMed] [CrossRef] [Google Scholar]

What is “swine flu”? – Official website of the Administration of St. Petersburg

March 10, 2015

What is “swine flu”?
Swine influenza type A (h2N1) is a highly contagious (contagious), acute disease characterized by a sudden onset, rapid coverage of a large number of people, pronounced fever and damage to the respiratory system.

How can you get swine flu?
Currently, swine influenza A (h2N1) virus is transmitted mainly by airborne droplets from person to person.

There are no data on the transmission of “swine flu” to humans as a result of their consumption of properly processed and cooked pork or other pork products. The “swine flu” virus dies when meat is cooked at 70°C.

Who is most at risk from the swine flu virus?
The most vulnerable segments of society in terms of the incidence of swine flu (h2N1):
1. Elderly people
2. Children attending organized groups (kindergarten, school, circles, etc.)
3. Persons who have been in close contact with a confirmed or suspected case (close contact involves being within 2 m of a sick person who is a confirmed or suspected case of swine influenza A(h2N1) virus infection)
4. Children and adults with chronic diseases
5. Travelers to countries with a high prevalence of swine flu
6. Customs officers
7. Health workers, etc.

What are the symptoms of swine flu?
The “swine flu” begins as an acute respiratory illness with the following symptoms: profuse nasal discharge or nasal congestion, sore throat, cough (with or without high fever).

How can you tell if a person has “swine flu” and not seasonal human flu?
A person has “swine flu” if they have an acute respiratory illness with a laboratory-confirmed infection with swine influenza A(h2N1) virus.

How long can a person with swine flu pose a danger to others?
People with swine flu are potentially dangerous to others up to 7 days from the onset of the first symptoms of the disease (nasal congestion, sore throat, cough, etc.). Children, especially the younger age group, can be dangerous to others for a longer period.

What can a swine flu patient do to limit the spread of the infection?
A person sick with swine influenza type A (h2N1) should wear a surgical mask when out of the house, follow the rules of personal hygiene (use of soap is mandatory when washing hands, face, nasal passages). Dishes and household items should be washed, as with seasonal flu (using special detergents).

What is the most effective treatment for swine flu?
For a confirmed or suspected diagnosis of swine influenza A (h2N1), either oseltamivir or zanamivir is recommended. Course duration – 7 days. The antiviral doses recommended for the prevention and treatment of swine influenza A (h2N1) are the same as those recommended for seasonal influenza.

Can anti-influenza drugs be used during pregnancy?
Because of the unknown effects that anti-influenza drugs (oseltamivir, zanamivir, amantadine, and rimantadine) have on pregnant women and the fetus, their use during pregnancy is justified only if the potential benefit outweighs the potential harm to the fetus.

What advice can you give to prevent swine flu?
– Try not to touch your eyes, nose or mouth, especially if you are in public places. Ventilate the room more often.
– If possible, postpone business and leisure trips to regions where cases of “swine flu” have been detected. First of all, it is necessary to refuse visits to the USA, Mexico, Spain, England, and other countries with a high spread of “swine flu”.
– If your trip to a country where cases of illness cannot be postponed, be careful not to visit crowded places, avoid using public transport, do not stand or sit near people with signs of a respiratory infection – runny nose, cough, red eyes.
– A four-layer gauze bandage or surgical mask must be worn.
– If you have returned less than 10 days ago from a country where cases of spread and infection with the swine flu virus have been recorded, be especially attentive to your health. If you have a fever, cough, runny nose and muscle pain, contact your doctor immediately.

Treatment of influenza A/h2N1 – Modern methods of treatment at the MCH

Prevention of influenza

Use common flu prevention measures:

1. Avoid close contact with people who appear unwell, show fever (fever) and cough.

2. Wash your hands thoroughly and often with soap and water.

3. Maintain a healthy lifestyle, including adequate sleep, healthy eating, physical activity.

If you already feel unwell with a fever, cough or sore throat:

1. Stay at home and avoid work, school or crowded places.

2. Get plenty of rest and fluids.

3. Cover your mouth and nose with available disposable tissues when coughing and sneezing, and dispose of used tissues properly.

4. Wash your hands thoroughly and often with soap and water, especially after coughing or sneezing.

5. Tell family and friends about your illness and try to avoid contact with people.

Differences between SARS, common flu and h2N1

If one of your family members falls ill:

1. Isolate the patient from other family members. Prevent them from approaching the sick person at a distance of less than 1 meter.

2. Cover your mouth and nose when caring for the sick. Either mass-produced or homemade masks are suitable for this purpose, provided they can be disposed of or disinfected after use.

3. Wash hands thoroughly with soap and water after each contact with a sick person.

4. Constantly ventilate the room where the sick person is. Use windows and doors for ventilation.

5. Keep the premises clean, use detergents when cleaning.

What to do if you need medical help:

1. Call the doctor at home and tell about the symptoms. Explain why you think you have influenza A/h2N1 (for example, if you have recently traveled to a country where there are human outbreaks of the disease). Follow the advice your doctor gives you.

2. If it is not possible to contact your healthcare facility in advance, report suspected infection as soon as you arrive at the facility.

3. Cover your nose and mouth while driving.

Treatment

The swine influenza A/h2N1 virus is resistant to the antiviral drugs amantadine and rimantadine, but susceptible to oseltamivir and zanamivir. Antiviral treatment is available with either zanamivir alone or in combination with oseltamir or amantadine or rimantadine and should be initiated at the first onset of symptoms. The recommended duration of treatment is five days. Recommendations for the use of antiviral drugs may change as new data on the susceptibility of viruses to certain drugs become available.

Among other drugs, it is recommended to take drugs such as Tamiflu, Arbidol, Amixin and other immune drugs as stimulants. These drugs are only effective as a preventive measure against swine flu, not as a cure for swine flu.

For prevention, you can also take vitamin C and adaptogens – tincture of Rhodiola rosea, Eleutherococcus, Schizandra, as well as cycloferon tablets or alpha-interferon in the form of an ointment for the nose.