The decision
to administer Lyme disease vaccine should be based on an assessment
of individual risk, which depends on a person's likelihood of
being bitten by tick vectors infected with B. burgdorferi..
This likelihood is primarily determined by the density of vector
ticks in the environment (which varies by place and season),
the prevalence of B. burgdorferi infection in vector ticks,
and by the extent of person-tick contact, which is related to
the type, frequency, and duration of a personÕs activities
in a tick infested environment.
The assessment
of risk should first consider the geographical distribution of
Lyme disease. The areas of highest Lyme disease risk in the United
States are concentrated within a few northeastern and north-central
states. A classification of overall Lyme disease risk by state
is shown in Table 1. The risk of Lyme disease differs greatly
not only between regions and states and counties within states
(as shown in Figure 1), but even within counties and townships.
Detailed information on the distribution of Lyme disease risk
within specific areas is best obtained from state and local public
health authorities.
The second
step in determining Lyme disease risk is to assess the individual's
activities. High risk activities are those that involve frequent
or prolonged exposure to the habitat of infected ticks at times
of the year when the nymphal stages of these ticks are actively
seeking hosts, which in endemic areas is from April through July.
Typical habitats of Ixodes ticks are wooded, brushy, or
overgrown grassy areas that are favorable for deer and the tick's
rodent hosts. Various recreational, property maintenance, occupational
or leisure pursuits that are carried out in tick habitat may
be high-risk activities.
When in highly
endemic areas, individuals can reduce their risk of Lyme disease
by avoiding tick infested habitat. If exposure to tick infected
habitat cannot be avoided, individuals may reduce their risk
of infection by applying repellents, wearing protective clothing,
and regularly checking for and removing attached ticks.
Individuals
who are unlikely to seek medical care for early manifestations
of Lyme disease may be at increased risk for Lyme disease complications.
Morbidity from Lyme disease can be significantly reduced detecting
and treating the infection in its early stages, since early and
correct treatment almost always results in a prompt and uncomplicated
cure.
