Baseline characteristics and serious adverse events during follow-up
| Baseline characteristics | JIA (n=68) | HC (n=55) |
|---|---|---|
| Mean (SD) age (years)* | 14.1 (±1.6) | 14.3 (±1.2) |
| Compliance with vaccination† | ||
| Received only one dose | 0 (0%) | 0 (0%) |
| Received only two doses | 1 (1%) | 1 (2%) |
| Received three doses | 66 (97%) | 50 (91%) |
| Third vaccine uncertain due to dropout | 1 (1%) | 4 (7%) |
| Study visit completion | ||
| Attended 3 months visit | 64 (94%) | 46 (84%) |
| Attended 7 months visit | 63 (93%) | 47 (85%) |
| Attended 12 months visit | 63 (93%) | 46 (84%) |
| Dropouts in total vaccinated cohort | 2 (3%) | 6 (11%) |
| (Serious) adverse events | 0 (0%) | 0 (0%) |
| Lost to follow-up | 0 (0%) | 2 (4%) |
| Withdrawn for personal reason | 2 (3%) | 3 (5%) |
| Venous punctures too demanding | 0 (0%) | 1 (2%) |
| Seropositivity at baseline | ||
| HPV16 | 2 (3%) | 0 (0%) |
| HPV18 | 1 (1%) | 1 (2%) |
| JIA subtype | ||
| Oligoarticular JIA, persistent‡ | 23 (34%) | |
| Oligoarticular JIA, extended‡ | 13 (19%) | |
| Polyarticular JIA, RF positive | 7 (10%) | |
| Polyarticular JIA, RF negative | 12 (18%) | ND |
| Systemic onset JIA | 6 (9%) | |
| Enthesitis related JIA | 1 (2%) | |
| Psoriatic arthritis | 2 (3%) | |
| JIA not specified | 4 (6%) | |
| Disease characteristics | ||
| ANA positive | 39/65 | |
| RF positive | 12/58 | |
| HLA-B27 positive | 4/25 | ND |
| Median (IQR) age at onset (years) | 9.4 (3.6–12.1) | |
| Median (IQR) duration of JIA (years) | 4.6 (1.7–10.4) | |
| Median (IQR) disease activity | ||
| JADAS-27 | 3.1 (1.2–6.8) | |
| Joints with active arthritis | 0 (0–1) | |
| Patient well-being assessment, 10 cm VAS§ | 1.9 (0.3–4.6) | ND |
| PGA of disease activity, 10 cm VAS§ | 0.9 (0–1.5) | |
| ESR, mm/h | 8 (5–12) | |
| Medication use | ||
| MTX | 24 (36%) | |
| Mean (SD) dose (mg/m2/week) | 10.2 (±3.1) | |
| NSAIDS | 37 (54%) | |
| Other DMARDS¶ | 6 (9%) | ND |
| Anti-TNFα treatment | 9 (13%) | |
| Median (IQR) dose (mg/week) | 45 (25–50) | |
| Anti-IL1 treatment | 1 (1%) | |
| Oral steroids | 0 (0%) | |
| SAEs | ||
| Participants reporting SAE | 11 (16%) | 1 (2%) |
| Number of SAEs reported | 14 | 1 |
| Surgery | 2 Preplanned surgeries Appendicitis Perforated eardrum Correction of cerebral AVM | 1 Preplanned surgery |
| Hospital admission | 3× diagnostic endoscopy** Analysis of gait abnormalities** Transient lower back pain Preplanned lasertherapy uveitis Allergic reaction anti-TNFα Epileptic insult: cerebral AVM Severe pharyngitis | None |
Unless otherwise indicated, frequencies (percentage) are depicted.
*p=0.36 (Student t test).
†The second HPV vaccination was postponed in three patients and the third HPV vaccination in four JIA patients.
‡52% (12/23) of the patients with persistent oligoarticular JIA and 85% (11/13) of the patients with extended oligoarticular JIA were ANA positive.
§Well-being and disease activity were both measured on a 10 cm VAS in which 0 represented ‘very well’ overall well-being or no disease activity, and 10 represented ‘very poor’ overall well-being or maximum disease activity.
¶Five patients used leflunomide (10–20 mg) and one oligoarticular JIA patient used mycophenolate mofetil for the treatment of severe uveitis.
**3 Patients underwent an endoscopy at which inflammatory bowel disease was diagnosed. In all 3 patients, abdominal pain, diarrhoea with the passage of mucus, periods of constipation and intermittent rectal bleeding were already present prior to the first HPV vaccine dose. Gait abnormalities in one patient had a psychosomatic cause.
ANA, antinuclear antibody; AVM, arteriovenous malformation; DMARDS, disease modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; HC, healthy control; HLA, human leucocyte antigen; HPV, human papillomavirus; IL, interleukin; JADAS-27, Juvenile Arthritis Disease Activity Score involving 27 joints; JIA, juvenile idiopathic arthritis; MTX, methotrexate; ND, not determined; NSAIDS, non-steroidal anti-inflammatory drugs; PGA, Physician Global Assessment of disease activity; RF, rheumatoid factor; SAE, serious adverse event; TNF, tumour necrosis factor; VAS, visual analogue scale.