for the diseases domestically (Institute of Medicine, 1985): for parainfluenza, 50 mild and 10 moderate episodes for each severe case, and for RSV, 30 mild and 10 moderate episodes for each severe case. In the absence of pathogen-specific data for developing countries, a case fatality rate (CFR) of 15 percent is assumed for H. influenzae and S. pneumoniae (based on CFRs for untreated and hospitalized ARIs; Pio et al., 1985). Hence, seven severe cases are presumed to occur for each death. All H. influenzae and S. pneumoniae episodes are assumed to be severe.
The relative case frequencies shown in Table B.5 are based on these assumptions. They were used to derive the disease burden distributions shown in Table B.6, and in Tables B.7, B.8, B.9, and B.10 for the individual pathogens.*
Advisers to the committee expressed concerns about the limited knowledge from which the estimates described above are derived. Certain features of acute respiratory infections led the committee to conclude that the available data are probably not entirely reliable because of suspected bias.
For example, many children with pneumonia may not reach the hospital, and those who do may represent a skewed sample. How to adjust available data for suspected biases is not known; hence, the procedures described above represent the only practical approach to developing the disease burden estimates needed for the overall assessment.
Berman, S., A.Duenas, A.Bedoya, V.Constain, S.Leon, I.Borrero, and J.Murphy. 1983. Acute lower respiratory tract illness in Cali, Colombia: A two-year ambulatory study. Pediatrics 71:210–218.
Bulla, A., and K.L.Hitze. 1978. Acute respiratory infections: a review. Bull. WHO 56:481–498.
Denny, F.W., and W.A.Clyde. 1983. Acute respiratory tract infections: An overview. Pediatr. Res. 17:1026–1029.
Institute of Medicine. 1985. New Vaccine Development: Establishing Priorities, Volume 1. Diseases of Importance in the United States. Washington, D.C.: National Academy Press.
Monto, A.S., and K.M.Johnson. 1968. Respiratory infections in the American tropics. Am. J.Trop. Med. Hyg. 17:867–874.
Pio, A., J.Leowski, and H.G.ten Dam. 1985. The magnitude of the problem of acute respiratory infections. Pp. 3–16 in Acute Respiratory Infections in Childhood, R.M.Douglas and E.Kerby-Eaton, eds. Adelaide, Aust.: University of Adelaide.
United Nations Children’s Fund. 1983. Statistics. Pp. 174–197 in The State of the World’s Children 1984. New York: Oxford University Press.