Introduction
Respiratory Syncytial Virus (RSV) is a common viral pathogen that causes
64 million acute respiratory infections annually1. RSV
is considered as a major cause of lower respiratory tract infections
amongst young children, elderly and immunocompromised adults
worldwide2-5, and is a frequent cause of
hospitalization6,7. In a recent systematic analysis,
it was associated to 6.6 million of acute lower respiratory infection,
where more than 1 million were hospitalized and 10000 dead in the
hospital8. For example, in the United States, RSV
infections cause between 58,000 and 80,000 hospitalizations each year in
children under 5 years of age and between 60,000 and 160,000 in adults
over 65 years of age9.
Based on the differences in the nucleotide sequence in the G protein,
RSV is divided into 45 genotypes. RSV-A has 15 genotypes whereas RSV-B
has 30 genotypes. Different RSV genotypes exhibit different
pathogenicities. In the same period and area, different RSV genotypes
can be co-epidemic, but most epidemics are dominated by one of the
subgroups or genotypes10. In the context of COVID-19
pandemic with resulting quarantine and barrier measures, a drastic
reduction of RSV infections has been observed in Europe and North
America1. Genetic characterization of RSV by direct
sequencing of sub-genomic regions or full genomic sequencing will be an
important part of RSV surveillance to monitor potential antigenic
changes in the circulating viruses that might affect the efficacy of
future immunization strategies. In general, the preferred RSV
surveillance will be an active sentinel system, with both primary care
and hospital patients being systematically sampled and tested for
RSV11. At present, data concerning the molecular
epidemiological characteristics of RSV subtypes are
limited12.
No effective therapy or vaccine is available to date, but vaccine
candidates and monoclonal antibodies are in late clinical
development5. Lately, a new monoclonal antibody
(nirsevimab) has been approved13,14. The effectiveness
of these therapies may vary depending on the type of virus. Therefore,
the reporting of RSV cases and the etiological diagnosis of the genotype
are very important for planning future public health measures and allow
appropriate treatment of the patient and avoidance of unnecessary
therapies (such as antibiotics)15.
Here, we conducted a study detecting and genotyping RSV, circulating in
clinical samples in Asturias from 2017 to 2022. The aim of this study is
to know the incidence and distribution of RSV types and to enrich the
data of epidemiological molecular studies on RSV in Spain.