RECONSTRUCTION AND PREDICTION OF THE HIV AIDS EPIDEMIC AMONG ADULTS IN THE EUROPEAN-UNION AND IN THE LOW-PREVALENCE COUNTRIES OF CENTRAL AND EASTERN-EUROPE/

Objectives: To reconstruct the HIV epidemic and to provide forecasts o f AIDS incidence among adults in the European Union (EU) and in a grou p of low prevalence (LP) countries of central and eastern Europe (incl uding the Asian republics of the former Soviet Union). Methods: An emp irical Bayesian back-calculation method was applied to AIDS incidence data reported by 31 March 1994. The HIV-infection curve was modelled a s a yearly step function and a seven-stage Markov model of disease pro gression, incorporating effects of pre-AIDS treatment, was used. Estim ation was by penalized maximum likelihood with empirical Bayesian smoo thing. Data were analysed by transmission group and, within the EU, by country. Predictions of AIDS cases to 1998 were made assuming constan t annual HIV incidence from 1993 onwards.Results: Estimated HIV preval ences per 100 000 population aged 15-59 years were, at 31 December 199 3, 198 (n = 447 800) in the EU and 2.7 (n = 6840) in the 22 LP countri es, with increases of 41% (EU) and 71% (LP) between 1989 and 1993. Amo ng homo/bisexual men in the EU, prevalence appears to have stabilized since 1989 and AIDS incidence appears to be reaching a peak. Among all prevalent HIV infections in the EU, 42% were estimated to be among in jecting drug users, 25% among homo-/bisexual men and 18% among persons infected heterosexually, compared with 29%, 35% and 19%, respectively , in the LP countries. Without allowing for the 1993 revision of the c ase definition, annual AIDS incidence is predicted to increase, betwee n 1994 and 1998, by 24% in the EU and by 48% in the LP countries, with the largest percentage increases among heterosexually-infected person s. Conclusion: The overall HIV prevalence rate is estimated to have be en about 70-fold lower in the LP countries than in the EU in the early 1990s, but to be increasing much more rapidly in the former. Moreover , recent reports of rapidly increasing HIV infection rates suggest tha t back-calculation may seriously underestimate the size of the epidemi c in the LP countries. Implementation of effective preventive measures is urgent if large-scale epidemics are to be avoided in the presently LP countries of the European region.