Economic impact of immunization against rotavirus gastroenteritis. Evidence from a clinical trial
R. I. Griffiths, G. F. Anderson, N. R. Powe, E. Oliveras, R. J. Herbert, C. C. Grant and B. L. Davidson
Department of Health Policy and Management, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD, USA.
OBJECTIVE: To estimate the economic impact of immunization against
rotavirus gastroenteritis in an infant population in the United States.
DESIGN: Cost identification and break-even analyses from the perspective of
society, nested within a phase 3, randomized, double-blind,
placebo-controlled trial. PATIENTS: Infants (N = 1278), aged 6 to 22 weeks,
enrolled during the summer and fall of 1991 and followed up until July 1,
1992. INTERVENTION: Immunization schedule of three doses of orally
administered tetravalent or serotype 1 rhesus rotavirus vaccine, or
placebo. MAIN OUTCOME MEASURES: Incidence of rotavirus gastroenteritis,
total direct medical costs, direct nonmedical costs, and indirect costs of
rotavirus and nonrotavirus gastroenteritis for the duration of the study
and of any illness during 5 days after each dose. The cost of the vaccine
was not included. RESULTS: Median total cost per infant among the 1187
infants who completed the immunization schedule was $9 in the tetravalent
vaccine group, $9 in the serotype 1 vaccine group, and $49 in the placebo
group (P = .01). Rotavirus gastroenteritis occurred in 195 infants (16%):
13% (51/398) in the tetravalent group, 12% (47/404) in the serotype 1
group, and 25% (97/385) in the placebo group (P < .0001). Of infants
with an episode of rotavirus gastroenteritis, the proportion who incurred
cost during the episode and the median cost during the episode did not
differ by treatment group. The baseline net cost savings for treatment of
rotavirus gastroenteritis and break-even cost of immunization were $11 per
infant for the tetravalent vaccine and $12 for the serotype 1 vaccine. In
sensitivity analysis, savings ranged from $40 to -$6, because of a large
variance in the costs of rotavirus gastroenteritis. CONCLUSION: The results
of the baseline analysis suggest that society should be willing to pay
between $11 and $12 for immunization against rotavirus. It might be willing
to pay an additional amount for the intangible benefits of reduced parental
inconvenience or anxiety associated with this illness in infants.
