The cost-effectiveness of vaccination against Lyme disease.

BACKGROUND: Vaccination against Lyme disease appears to be safe and effective; however, the cost per quality-adjusted life-year (QALY) gained with vaccination is unknown. METHODS: We developed a decision-analytic model to evaluate the cost-effectiveness of vaccination compared with no vaccination in individuals living in endemic areas of Lyme disease. Our analysis encompassed a 10-year time horizon including a 2-year vaccination schedule with an additional year of vaccine effectiveness. The costs and probabilities of vaccination risk, compliance and efficacy, and Lyme disease clinical sequelae and treatment were estimated from the literature. Health-related quality-of-life weights of the various clinical sequelae of Lyme disease infection were obtained from a sample of 105 residents from Nantucket Island, Massachusetts. RESULTS: Vaccinating 10 000 residents living in endemic areas with a probability of Lyme disease per season of 0.01 averted 202 cases of Lyme disease during a 10-year period. The additional cost per QALY gained compared with no vaccination was $62 300. Vaccination cost $12 600/QALY gained for endemic areas with an attack rate of 2.5% per season, and $145 200/QALY gained for an attack rate of 0.5%. Vaccinating individuals over an accelerated 2-month vaccination schedule improved the cost-effectiveness to $53 700/QALY gained. If a yearly booster shot is required for persisting efficacy, the marginal cost-effectiveness ratio increases to $72 700/QALY. The cost-effectiveness of vaccination was most sensitive to the Lyme disease treatment efficacy and assumptions about the persistence of vaccination effect. CONCLUSION: Vaccination against Lyme disease appears only to be economically attractive for individuals who have a seasonal probability of Borrelia burgdorferi infection of greater than 1%.

Lyme disease and preventive behaviors in residents of Nantucket Island, Massachusetts.

BACKGROUND: To determine the age-specific prevalence of Lyme disease and whether preventive behaviors on Nantucket Island correlate with Lyme disease, we surveyed island residents. METHODS: A survey with questions on Lyme disease symptoms, history, and preventive behaviors was mailed to all residents. Respondents were stratified by likelihood of having had Lyme disease. A subsample was selected for examination, and then classified according to the Lyme disease national surveillance case definition. RESULTS: The overall lifetime prevalence of Lyme disease for Nantucket residents was 15% (CI, 10%-19.8%): 19% among females, and 11% among males. The prevalence was highest among age groups 0-16 and 30-49 years. Overall, 86% of the population practiced at least one behavior. The most frequently reported preventive behavior was checking oneself for ticks (80%), followed by wearing protective clothing (53%), avoiding tick areas (34%), and using tick repellent (11%). Younger individuals practiced fewer preventive behaviors than older individuals (p=0.001). Although males reported greater tick exposure than females, females uniformly practiced preventive behaviors more frequently (p=0.001). The practice of preventive behaviors was not associated with a history of Lyme disease, but finding more than 5 ticks per year on oneself was (p=0.001). CONCLUSION: Lyme disease is highly prevalent on Nantucket Island. Young people are particularly at risk and health education should emphasize preventive behaviors less frequently practiced: using tick repellent, avoiding tick areas, and wearing protective clothing.

Musculoskeletal and neurologic outcomes in patients with previously treated Lyme disease.

BACKGROUND: Previous follow-up studies of patients with Lyme disease suggest that disseminated infection may be associated with long-term neurologic and musculoskeletal morbidity. OBJECTIVE: To determine clinical and functional outcomes in persons who were treated for Lyme disease in the late 1980s. DESIGN: Population-based, retrospective cohort study. SETTING: Nantucket Island, Massachusetts. PARTICIPANTS: 186 persons who had a history of Lyme disease (case-patients) and 167 persons who did not (controls). MEASUREMENTS: Standardized medical history, physical examination, functional status measure (Medical Outcomes Study 36-item Short Form Health Survey [SF-36]), mood state assessment (Profile of Mood States), neurocognitive tests, and serologic examination. RESULTS: The prevalence of Lyme disease among adults on Nantucket Island was estimated to be 14.3% (95% CI, 9.3% to 19.1%). In multivariate analyses, persons with previous Lyme disease (mean time from infection to study evaluation, 6.0 years) had more joint pain (odds ratio for having joint pain in any joint, 2.1 [CI, 1.2 to 3.5]; P = 0.007), more symptoms of memory impairment (odds ratio for having any memory problem, 1.9 [CI, 1.1 to 3.5]; P = 0.003), and poorer functional status due to pain (odds ratio for 1 point on the SF-36 scale, 1.02 [CI, 1.01 to 1.03]; P < 0.001) than persons without previous Lyme disease. However, on physical examination, case-patients and controls did not differ in musculoskeletal abnormalities, neurologic abnormalities, or neurocognitive performance. Persons with previous Lyme disease who had persistent symptoms after receiving treatment (n = 67) were more likely than those who had completely recovered to have had fever, headache, photosensitivity, or neck stiffness during their acute illness (87% compared with 13%; odds ratio, 2.4 [CI, 1.0 to 5.5]; P = 0.045); however, the performance of the two groups on neurocognitive tests did not significantly differ. CONCLUSIONS: Because persons with previous Lyme disease exhibited no sequelae on physical examination and neurocognitive tests a mean of 6.0 years after infection, musculoskeletal and neurocognitive outcomes seem to be favorable. However, long-term impairment of functional status can occur.

Outcomes of children treated for Lyme disease.

OBJECTIVE: To study the outcome of Lyme disease (LD) in children identified in a total population survey of an endemic island. METHODS: We conducted a population-based retrospective cohort study off the coast of Massachusetts. Twenty-five children who met the Centers for Disease Control case definition for prior LD were compared with 26 children without LD from the same community. All children with LD received antibiotics during the acute phase of their disease. All 51 children were invited for a clinical evaluation, including 12-lead electrocardiogram (EKG), and measurement of antibodies to Borrelia burgdorferi by antibody-capture ELISA and Western blot. RESULTS: At a mean of 3.2 years from the initial manifestation of LD, children with prior LD did not have a higher prevalence of musculoskeletal or neurological symptoms, examination abnormalities, abnormal EKG, or behavioral difficulties, compared to children with no history of LD. CONCLUSION: Children who receive appropriate antimicrobial therapy for LD appear to have no demonstrable longterm morbidity.

Symptoms, functional status, and neuromuscular impairment following carpal tunnel release.

This study examined the resolution of symptoms, functional limitations and neuromuscular impairments following carpal tunnel release. Thirty-five patients were evaluated preoperatively and 6 weeks, 3 months, 6 months, and a mean of 27 months postoperatively. Evaluation consisted of physical examination (performed in a subset of patients) and previously validated questionnaire scales measuring symptoms, functional limitations, and satisfaction. Nocturnal pain, tingling, and numbness improved within 6 weeks after surgery. Weakness and functional status improved more gradually. Grip and pinch strength worsened initially, returned to pre-operative levels after about 3 months, and improved significantly by 24 months. The Tinel and Phalen signs remained positive in two and seven patients, respectively, after 2 years, and two-point discrimination remained abnormal in over half of patients after 2 years. These temporal patterns should be discussed with patients to foster realistic expectations of the response to surgery.