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What should we know about the RSV virus circulating in the community at this time of year?

This year, widespread community spread of the RSV virus or respiratory syncytial virus was observed, along with influenza viruses and mutations of SARS-CoV-2. The extent was even to the extent that the Pediatric community considers that this infection is worthy of competing with the spread of COVID-19 in adults.

Epidemic outbreaks of the RSV virus occur every year. What is different this year?

• The virus did not follow the typical disease season this year, which is the months of January, February and a timely retreat in the spring, but expanded almost equally throughout the year, even in the summer months.
• The epidemic outbreak of the RSV virus this year is larger and more serious, while other viruses are also in circulation (SARS-CoV-2, influenza, enterovirus 68, rhinoviruses, parainfluenza).
• Speculations are made without being able to predict what severity the clinical picture will have in the event of co-infection, since the chronological appearance of the various viral infections has ceased, at least for this year, to be distinct.
• The flu also lost its specific time period of appearance of.

Why is the number of children infected with the RSV virus so high this year?

This is attributed to the “immune debt” that has existed. As a rule, the RSV virus causes infection in the 1st year of life and practically all children have already been immunized in the 2nd year of life.

Infection in the 1st 6 months of life is particularly serious due to bronchiolitis and/or pneumonia. Subsequent infections are mild with the type of common cold. With the measures taken for the SARS-CoV-2 virus in 2020, there was no RSV disease and thus the “immune debt” arose, resulting in the summer of 2021 with the relaxation of the measures, the virus reappeared with the infection persisting over time. The return to old social contact habits, with schools open and the abandonment of masks, unimmunized children from the 2020 measures will pay their “debt” this year.

It is also supported that the interaction of the SARS – CoV-2 virus with other co-circulating viruses has brought about a change in the epidemiology of RSV. This situation is characterized as “viral interference”.

Recently, the view has been circulating that a new strain of RSV has been created for which the child population lacks immunity. This, combined with the “immune debt” that has been created due to the measures, constitute the perfect combination for RSV to attack the community.

When will we return to the old epidemiology of RSV?

It is an interesting question that no one can answer at the moment. The possibility of preventive intervention, with the time-specific, due to the diachronic behavior of the virus, administration of the monoclonal antibody Palivizumab in 5 doses covering the period November – March, is conditional, given the spread of the virus throughout the year.

Will there be prevention of RSV with a vaccine?

The research so far is very promising and it seems that the efforts will soon be successful with two vaccines. One for infants, with the vaccine being administered during pregnancy so that there is transplacental passive immunization. The other vaccine will concern adults of advanced age in whom RSV causes serious illness. The long-term prophylactic administration of the monoclonal preparation Nirsevimab has already been approved by the competent European authorities for general use in children and not only for those at risk. In general, there is increased optimism for the available means of prevention (vaccine, monoclonals) within the next year.