Deworming and immunization campaigns

1
Deworming and immunization campaigns

• A. Montresor, D. Engels, H. Allen L. Savioli
• Parasitic Diseases and Vector Control
• World Health Organization

2
Purpose

• Discuss possible synergies between worm control
  and immunization campaigns
• Evaluate possible steps to promote the inclusion
  of deworming in immunization campaigns

3
Outline
next steps
synergies between deworming and immunization
campaigns
Effects of worm infections on health
4
Worm infections are associated with nutritional
deficiencies
Faecal occult blood (mg blood/g faeces)
0 lt2000 lt4000
lt6000 lt8000 gt8000
Stoltzfus 1996 Am J Trop Med Hyg 55 399-404
Yip, R., 1996 UNICEF, Viet Nam
5
Worm infections are associated with nutritional
deficiencies
Mean intensity of A. lumbricoides infection
Curtale 1995 J Trop Ped 41 334-337
6
Worm infections affect language and
memory development of children
U
U
I
I
Memory test
Fluency
(U) Uninfected control
(I) Infected
Nokes et al (1992) Parasitology 104 539-547
7
Treatment has positive effects on language and
memory development of children
U
U
T
I
I
Memory test
Fluency
(U) Uninfected control (T)Treated (I)
Infected (placebo)
Nokes et al (1992) Parasitology 104 539-547
8
Treatment has positive effects on language and
memory development of children
U
U
T
T
I
I
Memory test
Fluency
(U) Uninfected control (T)Treated (I)
Infected (placebo)
Nokes et al (1992) Parasitology 104 539-547
9
Individuals in a period of intense physical and
intellectual growth are at risk
neonate
Foetal
Infant
Preschool age
School-age
Reproductive age
0 1 2 3 4 5 10 15 20
40 60
A. lumbricoides - REDUCED GROWTH RATE
T. trichiura - reduced growth rate - TDS- iron
deficiency COGNITION DEFICIT
Hookworm IRON DEFICIENCY - ANAEMIA
Crompton and Nesheim Annu Rev Nutr 2002 35-59
10
Individuals in a period of intense physical and
intellectual growth are at risk
neonate
Foetal
Infant
Preschool age
School-age
Reproductive age
0 1 2 3 4 5 10 15 20
40 60
A. lumbricoides - REDUCED GROWTH RATE
T. trichiura - reduced growth rate - TDS- iron
deficiency COGNITION DEFICIT
Hookworm IRON DEFICIENCY - ANAEMIA
Crompton and Nesheim Annu Rev Nutr 2002 35-59
11
Periodic treatment reduces morbidity despite
re-infecton
Morbidity
12
Periodic treatment reduces morbidity despite
re-infecton
adapted from Guyatt et al. (1993) Trans.
R.Soc.Trop.Med.Hyg.
13
Outline
next steps
synergies between deworming and immunization
campaigns
children suffer from worm infections
14
Deworming boosts immuno-response
Chronic immune activation due to STH is
associated with

• impaired signal transduction
• and anergy
• Borkow G. et al. (2000), J. Clin Invest.106
  1053-1060

• decreased CD4 counts and
• increased CD8
• Kalinkovich A. et al. (1998) Clin.Exp. Immunol.
  114 414-421

Deworming increases cellular response Elias et al
(2000) Clin Exp Immunol 123 219-225
15
Deworming increases vitamin A absorption

• Possible mechanisms involved
• competition
• malabsorption

Mahalanabis et al (1976) Am J Clin Nut 29
1372-1375
16
Vitamin A distribution and immunization
campaigns reach a large number of children
In 1999, 97 million doses of Vitamin A were
distributed in 50 countries
73 of the countries endemic for STH are covered
by immunization campaigns reaching children over
one year
17
Deworming is cheap

• In Nepal the Vitamin A distribution programme
• costs 1.7 million USD a year
• Fielder J.L. (2000) Health Policy and
  planning. 15 145-156

• Adding anthelminthic treatment to the
  distribution
• costs 50,000 USD a year

18
These drugs are extremely effective and safe
Millions of doses have been distributed without
problems
Non medical personnel can easily and safely
distribute them
19
Multi-intervention strategy is effective

• When Vitamin A was distributed during NID
• attendance at NID increased
• the number of deaths averted increased
• the cost of averted deaths was reduced

Ching et al Am J Public Health 2000 91 1526-1529
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Outline
Next steps
Deworming and immunization campaigns
are ideal partners
Children suffer from worm infections
21

Strategy to promote deworming during NID or
Vitamin A distribution campaign /1
Consensus building

• discussions with responsible authorities of NID
  and Vit A
• distribution campaigns (WHO - UNICEF - donors)

• promotion of studies documenting advantages of
  combined
• intervention

22

Strategy to promote deworming during NID or
vitamin A distribution campaign /2
Promotion

• leaflets for decision-makers focusing on cost
  efficacy
• of joint intervention

• guidelines for managers focusing on the
  simplicity
• of the intervention

23

Strategy to promote deworming during NID or
vitamin A distribution campaign /3
WHO (HQ and RO) is ready to provide technical
support to countries, international organizations
and NGOs that are planning to introduce deworming
activities in ongoing immunization and
micronutrient supplementation programmes

24
Why deworm?

• Has relevant impact on health

• Is cheap

• Enhances coverage and efficacy of immunization
  campaigns