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Table 2 Estimated base-case values and their confidential intervals (CI) for input parameters in the Thai HIV cost-effectiveness model

From: Cost-effectiveness of models for prevention of vertical HIV transmission – voluntary counseling and testing and choices of drug regimen

Parameters

Point estimate

95%CI for sensitivity analysis

Parameter distribution

Data sources

Epidemiology

Maternal HIV infection rate

1.5%

  

Ref.19

ANC after gestational age 34 weeks

7.4%

6.7–8.0%

Beta

Ref.8

Rate of perinatal HIV transmission

18.9%

13.2–24.4%

Beta

Ref.3

Rate of transmission via breastfeeding

12.0%

7.0–17.0%*

Beta

Ref.22

Percent of HIV infection detected by second VCT

4.7%

2.70–7.5%

Beta

Ref.20

Rate of HIV infected mothers who, treated with NVP, developed HIV resistance to NVP

17.4%

12.0–22.7%

Beta

Ref.17

Rate of HIV infected mothers who need to be treated AIDS within a year after delivery

33.9%

29.6–38.3%

Beta

Ref.28

Efficacy of Antiretrovial therapy

Odds of transmitting the virus when mother received AZT > = 4 weeks versus placebo

0.46

0.35–0.60

Normal

Ref.23

Odds of transmitting the virus when mother received AZT < 4 weeks versus receiving AZT > = 4 weeks

1.40

0.82–2.38

Normal

Ref.24

Risk of transmitting the virus with NVP regimen versus placebo

0.51

0.33–0.79

Normal

Ref. 23

Risk of transmitting the virus with AZT+NVP regimen versus receiving AZT > = 4 weeks

0.23

0.05–0.41

Normal

Ref.6

Compliance to the Programme

Infected pregnant women who know their HIV status before or at 36 week of gestation and accept AZT

75%

70–90%

Beta

Ref.8

Infected pregnant women who know their HIV status after 36 week of gestation and accept AZT

65%

55–90%*

Beta

Assumption (see text)

Infected pregnant women who know their HIV status before or at 36 week of gestation, do not accept AZT but accept NVP

50%

30–70%*

Beta

Assumption (see text)

Infected pregnant women who know their HIV status before or at 36 week of gestation and accept NVP

85%

70–90%*

Beta

Assumption (see text)

Infected pregnant women who know their HIV status after 36 week of gestation and accept NVP

75%

70–90%*

Beta

Assumption (see text)

Infected pregnant women who know their HIV status before or at 36 week of gestation and accept AZT+NVP

84%

80–90%

Beta

Ref.17

Infected pregnant women who know their HIV status after 36 week of gestation and accept AZT+NVP

75%

70–80%*

Beta

Assumption (see text)

Programme unit cost

US$ 2003

   

VCT for HIV negative pregnancy

2.69

1.57–7.79

Gramma

Ref. 8

VCT for HIV positive pregnancy

7.10

3.82–14.54

Gramma

Ref. 8

HIV testing for baby born by infected mother

5.61

3.18–11.65

Gramma

Ref. 8

Cost of antepartum AZT (per weeks)

10.50

  

Thai Department of Health

Cost of intrapartum AZT

2.30

  

Thai Department of Health

Cost of infant AZT (per week)

17.20

  

Thai Department of Health

Cost of NPV for mother and infant

3.10

  

Price survey by authors

Breast milk substitutes (per 1 year)

175.90

  

Thai Department of Health

Incremental cost of switching from NNRTI-base treatment regimen to PI-based regimen

497

147–847

Gramma

Ref.29

Public sector health expenditure

Life time pediatric HIV/AIDS treatment cost

1,680

1,340–2,015

Gramma

Ref.30

  1. Note that a range for sensitivity analysis derived from 95% CI of each parameter distribution except * that based on assumption