NEW YORK (Reuters Health) Jul 16 – Lyme disease vaccine is cost effective only in the uncommon situation in which an individual is frequently exposed to ticks in a Lyme disease-endemic area, according to a report in the June issue of Arthritis & Rheumatism.
The high cost of the Lyme disease vaccine and the low risk of Lyme disease in most areas suggested to the authors the need for a cost-effectiveness analysis of the vaccine and an examination of the factors influencing its cost effectiveness.
Dr. Elizabeth Hsia and colleagues from University of Pennsylvania in Philadelphia performed a decision analysis of the cost effectiveness of Lyme disease vaccine under different assumptions of disease incidence and vaccine cost.
The incidence of Lyme disease proved to be the driving factor behind the cost effectiveness of vaccination, the authors report.
At the 0.0067% estimated national incidence of Lyme disease, the vaccination strategy that includes annual boosters would cost approximately $1.6 million per case averted, the report indicates.
The cost per case averted does not fall below $50,000 until the incidence of Lyme disease increases 30-fold, to 0.2%, the researchers note.
Only at a disease incidence of 10% does the vaccination with yearly boosters strategy become more effective and less costly than the no-vaccine strategy, the results indicate.
Other factors improve the cost effectiveness of Lyme disease vaccine include increasing years of susceptibility to the disease, increasing duration of vaccine protection, and increasing vaccine efficacy, according to the sensitivity analysis.
"At low incidences of Lyme disease, such as the average national incidence, vaccinating for Lyme disease is prohibitively expensive," the authors conclude. "However, at incidence levels observed in high-risk groups and highly endemic areas, the Lyme disease vaccine becomes a potentially cost-effective tool."
"Use of the Lyme disease vaccine should be done judiciously based on assessment of disease risk at an individual level," Dr. Hsia told Reuters Health. "This assessment should take into account both local geographic incidence of Lyme disease and personal history of tick exposure. When used in this fashion, the Lyme disease vaccine can be cost effective and vaccination should be recommended for only those with considerable individual risk.
"Why, then, will there probably be overuse and misuse of the OspA vaccine, just as there have been overuse and misuse (abuse) of antibiotics for treating Lyme disease and of serologic tests for detecting anti-B burgdorferi antibodies?" asks Dr. Leonard H. Sigal from University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School in New Brunswick, New Jersey in a related editorial. "Because Lyme disease has become a social phenomenon, a focus of public concern, a source of public anxiety."
"Since this editorial was written," Dr. Sigal writes in an addendum, "the OspA vaccine was removed from the market by the manufacturer due to poor sales, a decision dictated by the lack of profit and not by the presence of adverse reactions."
Arthritis Rheum 2002;46:1439-1442,1651-1660.