Cost-effectiveness of 

prevention:

Community-based interventions to control 

and prevent Lyme disease

Martin Meltzer, Ph.D., MS

Division of Preparedness & Emerging Infections (DPEI)

Centers for Disease Control and Prevention (CDC)

E-mail: qzm4@cdc.gov
Disclaimer

This presentation represents the work of the 

author and does not necessarily represent the 

policy or opinion of the CDC or DHHS.
What is . . . 

The cost-effectiveness of community-based 

Lyme disease control measures?
ANSWER:

Not sure

No readily accessible published studies.

WHY no available answer?

Missing/ non-existent data
What is cost-effectiveness?

Expressed as $/ per unit health outcome

E.g., $/ case averted

Cost per case = $ Intervention - $ saved

Cases averted
REMEMEBR

Cost-Effectiveness = Cost Savings

What is:

a ”reasonable” threshold?

the maximum “allowable” $/ case averted?

“Cost-Effectiveness” is SUBJECTIVE term 
FURTHER

Cost Savings = “Must Do”
Economics: Part of the "Decision pie"
4 data “buckets” needed for a good 

cost-effectiveness study

 Epidemiology and clinical

Who, when where, what happens

 Cost of clinical illnesses and outcomes

 Interventions

What, how well work, where, side effects?

 Must have a comparator

 Cost of interventions

 Must include $ of treating side effects
Epidemiological data: Risk clinical case

Confirmed cases / 100,000 population

Source: http://www.cdc.gov/ncidod/dvbid/lyme/ld_IncidenceRatesbyState20052009.htm

State 2007 2008 2009

Alabama 0.3 0.1 0.1

Alaska 1.5 0.9 1.0

Arizona 0.0 0.0 0.0

Arkansas 0.0 0.0 0.0

California 0.2 0.2 0.3

Colorado 0.0 0.0 0.0

Connecticut 87.3 78.2 78.2

Delaware 82.7 88.4 111.2

District of 

Columbia 19.7 12.0 8.8

Florida 0.2 0.4 0.4

Michigan 0.5 0.8 0.8
Epidemiological data: Risk clinical case

Source: http://www.cdc.gov/ncidod/dvbid/lyme/ld_Incidence.htm
Epidemiological data

Smith et al. Public Hlth Report 2001 (supp 1).
Epidemiological data

Risk factors:

Age: 10-19 years; and 50+ years of age

Rural > urban (3 times more)

Single homes, homes with woods, <100 ft to woods

Gardening + 4 hrs/ week

Other factors: not risk

MUST place risk in context

Geography, season, exact activity, ecology, etc.

Source: Smith et al. Public Hlth Report 2001 (supp 1).
Reported Lyme Disease Cases by Age 

Category, United States, 1992-2006

0

5000

10000

15000

20000

25000

30000 0–4 5–9 10–14 15–19 20–24 25–29 30–34 35–39 40–44 45–49 50–54 55–59 60–64 65–69 70–74 75–79 80–84 85–89

Age groups Cases per year
Clinical Features of Lyme Disease Cases 

Reported to CDC, United States, 1992-2006

0 20 40 60 80

EM

Arthritis

Bells palsy

Radiculopathy

Heart block

Percent of Cases
0

10

20

30

40

50

60

70

80

90 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Percentage

Erythema 

migrans

Arthritis

Neurological

Cardiac

Change in Frequency of Clinical 

Features, United States, 1992-2006
Bucket #2: Cost of case

Figure 2. Trend of direct medical cost of Lyme disease 1997-2000

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

Early Stage LD Late Stage LD Suspected LD Tick Bite Other

Average cost of Lyme disease ($ per case)

1997 2000

Note: $ costs in 2000 $

Source: Zhang et al. Emerg Infect Dis 2006
Bucket #2: Cost of case: outcome tree

Note: $ costs in 2000 $

Source: Zhang et al. Emerg Infect Dis 2006
Bucket #2: Cost of confirmed case

For each confirmed LD patient 

$2,970 direct medical cost 

$4,762 indirect medical cost, non-medical cost 

and productivity loss 

Economic burden of LD in U.S. (2000 $)

184 million dollars 

Conservative and underestimated 

Note: $ costs in 2000 $

Source: Zhang et al. Emerg Infect Dis 2006
Bucket #3: Interventions

Vaccination

Control tick hosts

Population reduction or exclusion

Personal protection

Control ticks

On hosts or on ground
Interventions: vaccine: analysis

Source: Meltzer et al. Emerg infect Dis 1999

Vaccinate?

YES

NO

Vaccinate?

Get LD?

No

Yes

Early LD?

Yes

No

Health outcome

No LD

Cardiac

Neurologic

Arthritic

Case resolved

Cardiac

Neurologic

Arthritic

Case resolved

No LD

Cardiac

Neurologic

Arthritic

Case resolved

Cardiac

Neurologic

Arthritic

Case resolved

Get LD?

No

Yes

Early LD?

Yes

No
Results: Cost effectiveness 

60% 70% 80%

-40

-20

0

$ per case averted ($'000)

Probability of early diagnosis and 

treatment of Lyme disease

60% 70% 80%

-40

-20

0

Probability of Lyme 

Disease: 0.005

Probability of Lyme 

Disease: 0.03

$50

$200

$100 Source: Meltzer et al. Emerg infect Dis 1999
Conclusions: Vaccine: Cost -effectiveness

Public health policy implications

Value in targeting by risk of LD

Value in increasing probability of correct eraly

diagnosis and successful treatment

Similar conclusions from:

Hsia et al. Arthritis & Rheumatism, 2002.
White footed mouse

White tailed deer

Natural hosts and reservoirs of B. burgdoferi

Interventions: Control hosts
Deer Reduction: NJ

Source: Jordan et al, J. Med Entomol, 2007
Personal protection: reduced risk: CT:

Protective clothing: 40% (95% C.I.: 30 – 50%)

Tick repellants: 20% (10% - 40%)

Checking for ticks: 0% Not effective

Spraying property: 0% Not effective

Note: case control: CT. 709 cases

Source: Vazquez et al Emerg Infect Dis 2008
Personal protection: In-yard

 Bathed within 2 hrs: 40% (95% C.I.: 22% – 77%)

 Tick repellants: 41% (N/A - 65%)

 Checking for ticks: 45% (6% - 68%)

 Fencing yard : 46% (10% – 66%)

 All else (spraying, landscape, etc.): No effect

Note: Case control: CT.: 364 cases enrolled

Source: Connally et al. Am J Prevent Med 2009
Self-Medicating applicators: History:

Duncan Applicators – 1970s onward

Source: http://www.wpazambia.com/ForSaleSpecialOffers/DuncanApplicator.html
Self-medicating applicators
Self-medicating applicators

Source; Norval et. al: Self medicating applicator for controlling pests on animals. 

U.S. Patent 5,357,902, Oct 25, 1994.
Impact of applicators:

White-tailed deer

Group Ticks* / 

deer

S.E.

Treatment: pesticide 3.4 1.1

Control: mineral oil 10.8** 3.0

*Ticks: Ixodes scapularis

** P < 0.0001

Source: Sonenshine et al Med Vet Entom 1996:10:1490154
Impact of applicators:

Nymphs: 5 sites

Source: Brei et al. Vect Borne Zoo Dis, 2009
Potential problem: Alternative hosts

 Mice not primary host for ticks nor primary reservoir for 

B. burgdorferi ss,

 Mice feed 10% all ticks ; 25% B. burgdorferi-infected ticks

Inconspicuous shrews feed 35% all ticks; 55% 

infected ticks

May require interventions for multiple species

Source: Dustin et al. Proc R Soc B, 2008
Applicators: What is missing? No. human cases

Number of ticks

(Infesting hosts, infected, questing, etc.)

Response A

Response B

OR
Ixodes scapularis

Source: CDC Public Health Image Library http://phil.cdc.gov/phil/home.asp

In other words: Don’t need this . . . 
Source: CDC Public Health Image Library http://phil.cdc.gov/phil/home.asp

Need this: Impact on risk of cases 
Bucket #4: $ of interventions

 $ vaccination - have/ had

 $ costs of other interventions

Appears to be mostly lacking
Bucket #4: Stated support

Source: Gould et al, Vect Borne Zoo Dis, 2008
Bucket #4: Beware

 What people say and what they do

 Often 2 very separate things

 Support of community intervention

 Depends upon perceptions

 Can you “see” cases?

 Compliance over time

 Incredibly big issue

 “poorly” measured – if at all.
Conclusions: Cost-effectiveness of 

community based interventions

 Lack adequate data

 Relationship: tick reduction and cases

 Effectiveness over time

 Compliance over time – usually drops

 Costs of interventions

 Sustained – can’t stop

 Costs of side effects of interventions
Conclusions: Cost-effectiveness of 

community based interventions

 What is needed:

 Field trial(s)

 Large

 Measure impact on cases

 Run for “some time”

 E.g., 3 – 5 years

 Measure changes in community acceptance

 More than 1 site

 Measure – different risks, attitudes, etc.