Influenza virus (IV) that causes a respiratory illness for humans is basically of 3 types A, B, and C. In fact, type A (IAV) is the most concerning since it’s responsible for annual epidemics and might pose a global pandemic. Besides, IV has a high mutation and replication rate which allows it to escape medical coping measurements. In addition, the ability of the virus to recombine new segments to its segmented genome causes an outbreak.
Influenza virus types (IAV, IBV, ICV and IDV):
-Both IAV and IBV pose a threat to the respiratory system of humans and ; also, while both are responsible for seasonal epidemics, only IAV might lead to a pandemic.
-ICV infection is often mild and it targets humans and pigs.
-IDV affects cattle and pigs
How does influenza spread?
Just like covid-19, IV transmits from a person to another through aerosol droplets. In other words, the droplets must come in contact with the mouth or nose, or inhaled in small room space. Hence, the virus causes respiratory diseases for humans such as pneumonia and acute respiratory failure, so complications might cost patients their lives.
Symptoms:
- Fever
- Headache
- Dry hoarse cough
- Chills or sweats
- Myalgia
- Malaise
Diagnosis:
When clinical diagnosis is the most important resolve, laboratory testing is only used for hospitalized patients or patients that requires specific diagnosis for specific treatment. Indeed, testing is done by rapid molecular assays due to fast and accurate results.
Treatment:
As a matter of fact, any of the 4 approved antiviral drugs is considered efficient for patients within the 48 hours of symptoms onset. To clarify, these flu drugs are oseltamivir (Tamiflu), zanamivir (Relenza), baloxavir marboxil (Xofluza) and peramivir (Rapivab). Furthermore, people who hasn’t acquired the infection will obtain 24 hours less illness upon infection and lower risk of complications. Moreover, annual influenza vaccination is still recommended to avoid the virus 100%.
Who is at a high risk to influenza complications?
- Young children
- People with underlying medical conditions
- The elderly since they have the highest hospitalization and mortality rate
- Pregnant women
- Immunocompromised individuals
Influenza vaccine and antiviral treatment efficiency:
Usually, vaccines and antiviral treatment is the major approach to deal with influenza. However, how IV has minimal response to vaccines and high resistance to antiviral measures has been always a debate. Therefore, designing IV vaccines aside from inactivated, live-attenuated and recombinant ones is the main step in fighting influenza. Consequently, Nano-particles, virus-like particles (VLP) and new formulations of vaccines are highly investigated to increase efficacy and quality.
References:
-Nuwarda RF, Alharbi AA, Kayser V. An Overview of Influenza Viruses and Vaccines. Vaccines (Basel). 2021 Sep 17;9(9):1032. doi: 10.3390/vaccines9091032. PMID: 34579269; PMCID: PMC8473132.
-Pleschka S. Overview of influenza viruses. Curr Top Microbiol Immunol. 2013; 370:1-20. doi: 10.1007/82_2012_272. PMID: 23124938.
-Gaitonde DY, Moore FC, Morgan MK. Influenza: Diagnosis and Treatment. Am Fam Physician. 2019 Dec 15;100(12):751-758. PMID: 31845781.
-Uyeki TM. Influenza. Ann Intern Med. 2021 Nov;174(11):ITC161-ITC176. doi: 10.7326/AITC202111160. Epub 2021 Nov 9. PMID: 34748378.