HIV in Canada and elsewhere 16 September 2004
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Nicholas Bennett,
Infectious Disease Postdoc/Clinician
Department of Pediatrics, University Hospital, Syracuse NY

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Re: HIV in Canada and elsewhere

I'm a little disappointed in Mark Bartlett's response as a worker at CDC in Canada. He would do well to look beyond his country's borders, and exercise a little imagination as well!

Just because HIV has not spread well into the heterosexual population in Canada does not mean the same is true elsewhere. Additionally, the fact that it is still a risk for MSM (men who have sex with men) implies that it likely IS an STD! Almost by definition one wonders how it is going to easily spread from MSM to the heterosexual population. In the early days, such unusual events were how the sexual spread was first laid down as a concrete idea (heterosexual partners of the normal risk groups).

HIV is one of the least efficient STDs in terms of transmission: perhaps a 0.1%-0.2% per-exposure risk of acquisition, modified by various other factors (e.g. it is around 0.8% per exposure for anal sex). It is one of the least efficient blood-borne infections as well, much worse than HepB or HepC. But it also one of the most deadly infections on the planet. A co-worker in my PhD lab once said: "It's not category three because it's easy to catch: it's category 3 because it's an incurable lethal infection." Even Ebola "only" has a 50-80% lethality. HIV probably surpasses 90%.

In the UK, heterosexual cases are around 50%. Spain in contrast has, last I heard, a high proportion of IV drug users compared to other countries. Each population at a continent, country and even city level will have their own demographics: in fact at one stage a "high risk" patient in the UK was "a man who had sex with a man from the USA", because the internal epidemic was at so early a level.

I fully appreciate the fact that to a large degree the statistics are reliant on self-reported risk factors, but they are also related to contract tracing and the overall history of the case. Is Mark Bartlett of the opinion that HIV exists as a virus and as an infection, but is just not a very good STD? In that case, he is perhaps quite right. But then I wouldn't particularly want to catch it! The trick of course is that with a low infectivity rate, in order to survive as a virus one would expect the infection to allow the host to live for an extended period of time in order to give it time to spread.

Which is exactly what we see.

One must also bear in mind that the doom-and-gloom message from the mid-1980s did a lot to change sexual attitudes, and there is a case to say that it was out of proportion to the actual threat. But of course that wasn't known at the time! Is it perhaps too much to ask that instead of looking at the current situation and questioning it, one should be happy that it didn't progress as feared? Would Mark Bartlett be happier if we mirrored Sub-Saharan Africa with the expectant destruction of the employee/parent/teacher age group for the next generation?

Competing interests: None declared