The REspiratory Syncytial virus Consortium in EUrope (RESCEU) is an Innovative Medicine Initiative (IMI) funded by the EU under the H2020 framework to define and understand the burden of disease caused by human respiratory syncytial virus (RSV) infection. RSV causes severe disease in individuals at the extremes of the age spectrum and in high risk groups. It was estimated that RSV was associated with 34 million cases of acute respiratory tract infection (ARTI), 3.4 million ARTI hospitalizations and 55,000 to 199,000 deaths in children <5 years in 2005 worldwide. The estimated burden of disease in older adults is comparable with non-pandemic influenza A (for which a vaccine is available). These estimates were based on limited data and there is a substantial gap in knowledge on morbidity and associated healthcare and social costs in Europe. New vaccines and therapeutics against RSV are in development and could soon be available on the European market. RESCEU will deliver knowledge of the incidence and burden of RSV disease in young children and older adults in Europe, which is essential for stakeholders (governments, etc.) to take decisions about prophylaxis and treatment.

Objective:

To determine the burden of disease due to RSV in older adults.

Study design:

Prospective epidemiological, observational, multi-country, multicenter cohort study.

Study population:

Adults aged 60 years and up (n=1,000) of which approximately 50% is above 75 years of age.

Main study parameters/endpoints:

The primary endpoints of the study are;

• The incidence of RSV infection-associated ARTI.
• RSV associated medically attended (MA) ARTI.
• RSV related hospitalization.

In total, 1000 participants are recruited in three European countries (the Netherlands, Belgium and the United Kingdom). Participants, older adults above the age of 60 years, are recruited from general practitioners offices. Individual participants will be followed for one year (at least one winter season). For the individual participant the study procedures are described below:

Baseline visit:

Baseline visits are performed either at home or at the participating site before the start of the RSV season. The beginning of the season is to be determined per site in accordance to the local virologic surveillance reports. In general, baseline visits are performed between August and the beginning of October.

A questionnaire on demographic, social and clinical status is completed during this visit. Additionally, vital signs are recorded such as oxygen saturation, heart frequency and breathing frequency. During the baseline visit a blood sample (60 ml, serum, paxgene, whole blood) and nasopharyngeal swab (microbiome) will be collected.

Weekly follow-up during the RSV season:

From October until May participants are contacted weekly to check whether there are signs of a respiratory tract infection. If respiratory symptoms are present, the study team will perform a home visit or ask the participant to visit the site to perform a rapid Polymerase Chain Reaction (PCR)-based point of care test (POCT) for RSV using a nasopharyngeal swab. Additionally both an oro- and nasopharyngeal swab are collected for standard PCR, vital signs are recorded. Participants are asked to complete a daily dairy on respiratory symptoms, health care use and quality of life during 28 days from the moment of infection. If symptoms are not present anymore for two consecutive days, the participant can stop completing the diary.

In case of a positive RSV infection, additional sampling is performed by the study team. This consists of a nasopharyngeal swab (microbiome) and blood (Serum/PaxGene/whole blood). The same materials (minus serum and PaxGene sample) are collected again in convalescence (1-2 weeks after infection).

End of season visit:

At the end of the RSV season (May-June), again sampling is performed combined with recording vital signs. Samples collected are; blood (serum/PaxGene) and a nasopharyngeal swab (microbiome). In addition, a questionnaire will completed on respiratory symptoms, health care use, social status and quality of life.

Inclusion Criteria:

• Male and female adults ≥60 years of age (comorbidity, including chronic heart disease is not an exclusion criterion)
• Willing and able to give written informed consent
• Willing and able to adhere to protocol-specified procedures

Exclusion Criteria:

• Unable to perform the study procedures
• Current alcohol or drug abuse or history of unsuccessfully treated alcohol or drug abuse within the past year
• Dementia
• Life expectancy less than 1 year
• Any known or suspected immunosuppressive condition, acquired or congenital, as determined by history and/or physical examination (a more detailed description/list can be found in appendix 3 of the study protocol).
• Chronic administration (defined as more than 14 continuous days) of immunosuppressants or other immune-modifying drugs within 6 months prior to study participation. The use of topical, inhaled, and nasal glucocorticoids will be permitted (a more detailed description/list can be found in appendix 3 of the study protocol).
• Previous participation in this study or in a RSV interventional trial (vaccine, antivirals).
• Planned leave/holiday during the winter season of more than 1 month in total.

Cohort of approximately 1,000 older adults (≥60 years, including approximately 500 ≥75 years). Participants will be randomly recruited from the database of general practitioners in the following countries: the Netherlands (University Medical Centre Utrecht), Belgium (University of Antwerp) and United Kingdom (University of Oxford).