Blackpool, UK FY3 8NR
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Tyler is still struggling to interpret the De Souza study (1). Perhaps
I can simplify it for him. There were 2 groups of mothers, those who
received prenatal zidovudine, and those who did not. The overall
transmission to their infants was much greater in those who received no
zidovudine (22.5%, 34/151) compared to those on zidovudine (12.2%,
17/139) – a clear and significant benefit. It is patently incorrect to
claim, as Tyler has done, that there is a poorer outcome in the
There was a higher proportion of rapid progressors in the HIV-infected infants who had zidovudine (12 of the 17) than in the no zidovudine arm (10 of the 34). Since rapidly progressive HIV infection in infants is something that is linked to early in-utero HIV infection, and which could not therefore be preventable by any HIV drug use in later pregnancy, it is unsurprising that there were similar numbers with this outcome in each group (10 vs 12).
Obviously there were relatively more of the HIV infected infants in the zidovudine arm who did actually have rapid progression (12/17, 70.6%), since there were fewer transmissions overall (17). How Tyler can twist this to say zidovudine results in a poorer outcome is beyond me.
Perhaps an analogy will help. Let’s compare the wearing of seatbelts in road traffic accidents. In the group who do not wear seat belts, 34 (22.5%) are injured, 10 of these more seriously. In the seat belt wearers, only 17 are injured (12.2%), but 12 of these are more serious. My logical conclusion is that wearing a seatbelt is of overall benefit (but probably make little difference for some types of nasty accident). Tyler’s "logic" says seat belts are obviously dangerous because they "cause" more serious injuries. I know which group I'd rather be in.
(1) de Souza R; Gómez-Marín O, Scott G, Guasti S; O'Sullivan M; Oliveira R; Mitchell C. Effect of Prenatal Zidovudine on Disease Progression in Perinatally HIV-1–Infected Infants. JAIDS 2000; 24(2);154-161.
Competing interests: None declared