Antivirals and influenza: frequency of resistance
1Department of Epidemiology, University of Michigan, Ann Arbor, MI 48109-2025, USA. asmonto@umich.edu
Abstract:
Antivirals are effective in prophylaxis and therapy for influenza and are likely to be active against a new pandemic variant. They can be divided into the M2 inhibitors, adamantane and rimantadine, and the neuraminidase inhibitors (NAIs), zanamivir and oseltamivir. The former are limited in activity to type A viruses, whereas the latter are also active against type B viruses. Both classes of drugs appear similarly efficacious in prophylaxis at approximately 70-90%. However, use of M2 inhibitors (adamantanes) in therapy is limited by side effects, more common with amantadine, and also by production of antiviral resistance and lack of demonstrated prevention of complications. The NAIs prevent both types of seasonal influenza, shorten duration of illness, and reduce complications. As such, their use for seasonal influenza treatment has been increasing. They are active against A(H5N1) but oseltamivir has been most extensively stockpiled because the infection in humans may be disseminated. Resistance does emerge, but not at the same frequency as with the M2 inhibitors. Resistant viruses also appear less fit and thus less able to spread. However, as use increases, resistance needs to be carefully monitored.
Insights
Antiviral drugs, including M2 inhibitors and neuraminidase inhibitors (NAIs), are effective for influenza prevention and treatment. NAIs are preferred for therapy due to fewer side effects and broader activity against influenza types A and B.
Area of Science:
- Virology
- Pharmacology
- Infectious Diseases
Background:
- Antiviral medications are crucial for managing influenza, offering both prophylactic and therapeutic benefits.
- Two main classes of antivirals exist: M2 inhibitors (adamantanes) and neuraminidase inhibitors (NAIs).
- M2 inhibitors target influenza A, while NAIs are effective against both influenza A and B.
Purpose of the Study:
- To review the efficacy and limitations of current antiviral drugs for influenza.
- To assess the suitability of antivirals against potential pandemic influenza strains.
- To compare the therapeutic profiles of M2 inhibitors and NAIs.
Main Methods:
- Literature review of existing studies on influenza antiviral efficacy.
- Analysis of drug mechanisms of action and resistance patterns.
- Comparison of prophylaxis and therapy outcomes for M2 inhibitors and NAIs.
Main Results:
- Both M2 inhibitors and NAIs demonstrate high efficacy (70-90%) in influenza prophylaxis.
- NAIs are more suitable for therapy due to broader activity, fewer side effects, and prevention of complications compared to M2 inhibitors.
- NAIs show activity against avian influenza A(H5N1), with oseltamivir being widely stockpiled.
Conclusions:
- Neuraminidase inhibitors are increasingly recommended for seasonal influenza treatment and prophylaxis.
- Antivirals are likely effective against new pandemic influenza variants, with NAIs being a preferred option.
- Careful monitoring of antiviral resistance is essential as drug usage increases.
More Related Videos
09:07Using Zebrafish Models of Human Influenza A Virus Infections to Screen Antiviral Drugs and Characterize Host Immune Cell Responses
Published on: January 20, 2017
05:21A Luciferase-fluorescent Reporter Influenza Virus for Live Imaging and Quantification of Viral Infection
Published on: August 14, 2019
Related Concept Videos
01:27Influenza
01:25Inhibitors Of Virion Release
01:22Antiviral Nucleoside Inhibitors
01:30Inhibitors of Viral Protein Synthesis
01:26Pharmacokinetics: Drug–Food and Drug–Viral Interactions
01:10Retrovirus Life Cycles