Novel Lyme Disease Vaccine Effective Across All Ages

Medscape

2 days ago

An investigational vaccine for Lyme borreliosis, VLA15, was safe, well-tolerated, and immunogenic in people aged between 5 and 65 years, with children and adolescents showing notably stronger responses than adults.
METHODOLOGY:
Researchers assessed the safety and immunogenicity of the Lyme borreliosis vaccine candidate VLA15, administered using different vaccination schedules, in an ongoing randomized phase 2 trial conducted across multiple sites in Lyme borreliosis-endemic regions of the US.
They enrolled 625 participants (median age at screening, 23 years; 51% women), including children (5-11 years), adolescents (12-17 years), and adults (18-65 years).
Participants within each age cohort were randomly assigned to receive either VLA15 (180 µg) at months 0, 2, and 6 (three-dose regimen); VLA15 at months 0 and 6 with placebo at month 2 (two-dose regimen); or placebo at months 0, 2, and 6.
The primary immunogenicity endpoint was the immunoglobulin G (IgG) response against outer surface protein A (OspA), measured using an enzyme-linked immunosorbent assay, at month 7 post-vaccination (1 month after the final vaccine dose) across all age cohorts.
The primary safety endpoint was the frequency of solicited local and systemic adverse events within 7 days after any vaccination.
TAKEAWAY:
OspA-specific IgG geometric mean titers at month 7 were significantly higher in both VLA15 groups than in the placebo group ( P < .0001), with the three-dose regimen group showing higher titers (333.2-656.0 units/mL) than the two-dose regimen group (197.3-460.3 units/mL).
< .0001), with the three-dose regimen group showing higher titers (333.2-656.0 units/mL) than the two-dose regimen group (197.3-460.3 units/mL). Immune responses showed an age-specific pattern, with geometric mean titers from the three-dose regimen being highest in children (706.6-1364.1 units/mL), followed by adolescents (514.6-909.5 units/mL) and adults (201.6-419.3 units/mL). Similar trends were observed with the two-dose regimen.
Although antibody levels waned between months 7 and 12 in both VLA15 groups, they remained above baseline, with age-dependent patterns persisting.
Solicited local and systemic adverse events were more common in the VLA15 group, though none were of grade 4. No deaths were reported during the 12-month duration of the trial.
IN PRACTICE:
'VLA15 represents an important advance in the prevention of Lyme borreliosis. It covers a broad spectrum of serotypes and has a favorable safety profile in both children and adults,' the authors of a commentary wrote.
SOURCE:
This study was led by Laura Wagner, Valneva Austria, Vienna, Austria. It was published online on April 25, 2025, in The Lancet Infectious Diseases .
LIMITATIONS:
This trial had limited racial diversity, was conducted exclusively at sites in the US, and excluded individuals older than 65 years.
DISCLOSURES:
This study was funded by Pfizer and Valneva. Few authors reported being current or former employees or paid consultants of Valneva, with possible stock or stock option holdings. One author reported being a former employment at Pfizer, with possible stock or stock option holdings.