Safety and Immunogenicity of an Intranasal Vaccine for Respiratory Syncytial Virus in Seronegative Children 6-36 Months

Solicited adverse events (AEs)

Frequency of solicited AEs will be measured, categorized by severity. Solicited AEs are predefined AEs that may occur after investigational vaccine administration

Time frame: Immediate post-vaccination period

Unsolicited AEs

Frequency of unsolicited AEs will be measured, categorized by severity. Unsolicited AEs are any untoward medical occurrences in a participant administered the investigational vaccine, regardless of causal relationship to the investigational vaccine. Unsolicited AEs can include unfavorable and unintended signs (including abnormal laboratory findings), symptoms, or diseases temporally associated with the use of the investigational vaccine.

Time frame: Immediate post-vaccination period

Serious adverse events (SAEs)

Frequency of SAEs will be measured, categorized by vaccine-relatedness . SAEs are AEs, whether considered causally related to the investigational vaccine or not, that threaten life or result in any of the following: death, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or congenital anomaly/birth defect.

Time frame: Full study duration, an average of 1 year

Medically attended adverse events (MAEs)

Frequency of MAEs will be measured, categorized by vaccine-relatedness. MAEs are AEs, whether considered causally related to the investigational vaccine or not, with unscheduled medically attended visits, such as urgent care visits, acute primary care visits, emergency department visits, or other previously unplanned visits to a medical provider. Scheduled medical visits such as routine physicals, wellness checks, 'check-ups', and vaccinations, are not considered MAEs.

Time frame: Full study duration, an average of 1 year

Change in RSV-specific serum neutralizing antibody (nAb) titers (GMT)

Change in serum RSV-specific neutralizing antibody (nAb) titers will be measured per participant.