Surveillance Study of Respiratory Syncytial Virus Infection (RSV) in Subjects < 24 Months of Age

There is no vaccine available to prevent Respiratory Syncytial Virus disease; however, a
humanized monoclonal antibody is approved for the prevention of Respiratory Syncytial Virus
infection in pediatric patients at high risk of disease (eg, pre-term infants, congenital
heart disease, and chronic lung disease). Beyond this high-risk group, infection is common
in otherwise healthy infants and can be severe, leading to hospitalization and while
uncommon, death. Each year in the United States, approximately 100,000 Respiratory Syncytial
Virus-related hospitalizations occur in low risk infants. Currently, treatment of infants
suffering from Respiratory Syncytial Virus disease is limited to supportive care with the
goal of maintaining adequate oxygenation and nutrition.

The availability of a novel anti-Respiratory Syncytial Virus therapeutic that reduces the
number of hospitalizations related to Respiratory Syncytial Virus infection would fulfill an
unmet medical need in the pediatric population. For maximum effect, such a treatment should
be administered as early as possible in the course of infection. Accordingly, the
opportunities for early intervention with an anti-Respiratory Syncytial Virus therapeutic
are in the outpatient setting, prior to hospitalization. However, the incidence of
Respiratory Syncytial Virus-related hospitalization, as well as the natural history and
viral dynamics of Respiratory Syncytial Virus infection, remain undefined in the outpatient
setting. A better understanding of the prevalence of Respiratory Syncytial Virus infection
and subsequent hospitalization rates among symptomatic infants as well as the early disease
course of Respiratory Syncytial Virus infection will help in the design of clinical trials
needed to assess the efficacy of an anti-Respiratory Syncytial Virus therapeutic developed
by Gilead Sciences.

Inclusion Criteria:

- < 24 months of age

- ≥ 35 weeks gestational age at birth

- Signs of acute Respiratory Tract Infection < 5 days

- Ability to contact parent or legal guardian for follow up

Exclusion Criteria:

- Ongoing Respiratory Tract Infection

- Lung disease

- Heart disease

- Respiratory Syncytial Virus medication in the last 6 months

- Participation in a study with investigational medicinal product in the last 28 days