Respiratory tract infections (RTIs) are considered as one of the most common infectious diseases with high prevalence and large impact on the healthcare system [1]. For most of the respiratory tract infections, the symptoms are very similar. However, the clinical approach and treatment for each virus is different [2].

Because of the symptom similarity and possible risk of co-infection, multiple molecular assays has been developed for detecting each pathogen from respiratory patient specimen [3]. Diagnosis of these pathogens is also crucial for prevention of transmission especially among elderly patients and immune defective patients [4].

Influenza, a contagious viral infection transmitted through respiratory droplets, primarily affects the upper respiratory tract but can involve other organs. It can lead to serious complications such as pneumonia, increasing morbidity and mortality, especially in vulnerable populations. Influenza viruses belong to the Orthomyxoviridae family, with diverse antigenic characteristics. Influenza A, the most common type, can be further classified based on surface proteins, while influenza B has fixed antigenic characteristics [5].RSV, a non-segmented negative-strand RNA virus belonging to the Pneumoviridae family, consists of two strains (subgroups A and B). It is a contagious disease primarily affecting infants, with a mortality rate of 0.3% in hospitalized children and immunocompromised elderly individuals who face the highest risk of death [6, 7]. Because the symptoms of these viral diseases are similar, conducting laboratory tests is the most effective method of diagnosis.

Multiplex RT-PCR assays offer a rapid and highly sensitive means of detecting a broader spectrum of respiratory viruses compared to immunofluorescence (DFA) and viral culture methods. The ability to identify multiple pathogens in a single test represents a significant advancement in diagnostics, enabling a better understanding of the implications and clinical importance of co-infections [5].

REFERENCES
1. A. Zumla, J.A. Al-Tawfiq, V.I. Enne, et al. Rapid point of care diagnostic tests forviral and bacterial respiratory tract infections — needs, advances, and futureprospects. Lancet Infect Dis, 14 (11) (2014), pp. 1123-1135.

2. Leung, E. C. M., Chow, V. C. Y., Lee, M. K. P., Tang, K. P. S., Li, D. K. C., & Lai,R. W. M. (2021). Evaluation of the Xpert Xpress SARS-CoV-2/Flu/RSV assay forsimultaneous detection of SARS-CoV-2, influenza A and B viruses, and respiratorysyncytial virus in nasopharyngeal specimens. Journal of clinical microbiology, 59(4), 10-1128.

3. Kim, T. Y., Bae, G. E., Kim, J. Y., Kang, M., Jang, J. H., Huh, H. J., … & Lee, N.Y. (2022). Evaluation of the Kaira COVID-19/Flu/RSV Detection Kit for detection of SARS-CoV-2, influenza A/B, and respiratory syncytial virus: A comparative study with the PowerChek SARS-CoV-2, influenza A&B, RSV Multiplex Real-time PCR Kit. PLoS One, 17(12), e0278530.

4. Farfour, E., Yung, T., Baudoin, R., & Vasse, M. (2022). Evaluation of four fully integrated molecular assays for the detection of respiratory viruses during the cocirculation of SARS-CoV-2, influenza and RSV. Journal of Clinical Medicine, 11(14), 3942.

5. Neopane, P., Nypaver, J., Shrestha, R., & Beqaj, S. (2022). Performance Evaluation of TaqMan SARS-CoV-2, Flu A/B, RSV RT-PCR Multiplex Assay for the Detection of Respiratory Viruses. Infection and Drug Resistance, 5411-5423.

6. Crowe JE Jr, Williams JV. Paramyxoviruses: respiratory syncytial virus and human metapneumovirus. Viral Infect Human. 2014;601–627.7. Thompson WW, Shay DK, Weintraub E, et al. Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA. 2003;289(2):179–186.