A novel investigation into the North American spread of hepatitis C virus permits blame shifting, which the authors Jeffrey Joy and colleagues hope will increase the number of baby boomers who undergo testing. The medical community can now take its share of the responsibility for hepatitis C virus infection in its conversations with the 1945-65 birth cohort. Joy and colleagues off er evidence that the era of high rates of transmission and rapid expansion of hepatitis C virus infections was from 1940 to 1960, when reuse of glass and metal syringes was common medical practice. It was the medical community that inadvertently spread the virus in North America via nosocomial transmission. Current thinking attributes the high seroprevalence of hepatitis C virus among baby boomers to the risky individual behavior of the Woodstock generation in the late 1960s. 2,3 But by that time, which brought widespread experimentation with drugs, expansion was already slowing down. The authors conclude that attributing the spread of hepatitis C virus to the medical establishment, rather than youthful behavior long outgrown by most baby boomers, could justify changing the message around screening of baby boomers.
Joy and coworkers posit that the greatest expansion of North America’s most common genotype occurred between 1940 and 1960. Using phylogenetic analysis of genotype 1a sequences, they showed that diversity in the genes for five key proteins of the virus exploded in this period, but remained relatively stable after 1960. They reconstructed the demographic history of the epidemic by inferring the time at which a common ancestor virus strain emerged. 4 After screening 45 316 samples from the National Center for Biotechnology Information GenBank nucleotide database dating from around 1980 onwards, the team established the age of the various mutations and then determined the population size at given points in time. The Bayesian skyline plots shown in figure 1 of the Article have a y axis that is related to the number of infected individuals and their frequency of transmitting their strains of hepatitis C virus to others. The x axis represents time.