Global age-related seroprevalence for adeno-associated virus serotype 9 immunoglobulin G

Adeno-associated virus serotype 9 antibody (AAV9-Ab) immunoglobulin G titers, which may vary according to region or age, are required to be tested to ensure individuals with spinal muscular atrophy (SMA) are within the ≤1:50 threshold and eligible for intravenous onasemnogene abeparvovec treatment. This cross-sectional analysis evaluated AAV9-Ab immunoglobulin G titers by region or country, year, and age in a population of individuals with SMA from a wide range of countries (excluding the United States and Japan). Anonymized serum samples were utilized for total AAV9-Ab immunoglobulin G enzyme-linked immunosorbent assay tests (2020–2025). A total of 4,149 samples from individuals with documented age and first test information from 75 countries were analyzed. AAV9-Ab immunoglobulin G data were similar by region, country, and year, except for a greater proportion of individuals with AAV9-Ab immunoglobulin G titers ≥1:100 from Russia compared with other countries. Individuals in the 0-month age group had greater likelihood of AAV9-Ab immunoglobulin G titers ≥1:100 than those in other age groups. Logistic regression analysis revealed that the predicted AAV9-Ab immunoglobulin G titer significance probability was elevated at 0 months, declined up to 12 months, and then steadily increased from 12 to 24 months of age. In conclusion, our analyses confirmed age-related AAV9-Ab immunoglobulin G seroprevalence. Adeno-associated virus serotype 9 antibody (AAV9-Ab) titers are required to be ≤ 1:50 for onasemnogene abeparvovec treatment. van Olden and colleagues conducted a large, international study of AAV9-Ab titer records in participants with spinal muscular atrophy. AAV9-Ab titers were generally consistent by region and year but demonstrated substantial age-related variation.