Tuesday, February 15, 2011

HIV Does Not 'Die in Seconds' Outside the Body; it Can Live for Days

Sometimes a myth becomes so much repeated that it is almost impossible to persuade people even to think about it and consider if it makes any sense. One of those myths is that 'HIV only survives for seconds/milliseconds outside the body'.

Many people all around the world have been shown to have been infected by contaminated medical equipment. Millions have been infected by reused, unsterile injecting equipment. And it's not only contaminated blood that is dangerous, the virus can also be spread by anal mucus, vaginal mucus, pus and many other bodily fluids. Numerous artefacts can be contaminated this way, including latex gloves, scalpels, probes, etc.

If the virus only survived for seconds there would be no need to recall people when a medical practitioner is discovered to have been working without following procedures. Yet such recalls are commonplace, with thousands of former patients having to be tested every year. Would so much time and effort be wasted if the virus only survived for seconds?

To put it differently, how would you like to visit a dentist, surgeon or gynecologist who didn't sterilize their equipment, change their gloves or dispose of non-reusable items? Would you be willing to take a chance, if you suspected a practitioner of doing any of these things, just because you thought HIV only survived for seconds?

The myth itself is often presented very briefly and without much context. But what about the type of bodily fluid involved, concentration of the virus, the nature of the surrounding medium, temperature, moisture content, volume, whether pieces of tissue are involved, etc? What about whether the virus is cell-free or cell-associated?

Van Beuren et al investigated this in 1993 but authorities such as the US Center for Disease Control (CDC) don't seem to have noticed yet. Under the right conditions, HIV can survive for several days, perhaps even a week. Sure, it may become less viable over time, but billions of injections and other invasive medical procedures are given every year.

Kramer et al go into the matter in further detail in a more recent paper. Their literature review finds that blood borne viruses such as HV and hepatitis B virus (HBV) "have been shown to persist from only a few hours up to 7 days". That's hours, not seconds or milliseconds. Other pathogens can survive weeks or even months.

CDC is not very clear on the matter and they do not mention seconds, they mention hours, which is quite another matter. They say that the virus "doesn't survive well" and warn against interpreting tests carried out in laboratory conditions which use artificially high concentrations of HIV.

They may be right in saying that such concentrations are not found in nature, but a reused syringe or other medical equipment is not nature. "Contact with an environmental surface" may not be a threat, but you don't want a contaminated "environmental surface" getting under your skin.

Some people express the worry that HIV positive people can be stigmatized if others believe certain things about HIV. At one time, people believed they could be infected by shaking hands with a HIV positive person, sharing cutlery, etc. These, and many other things, are not risks. But invasive medical procedures are quite different; unsterile equipment can transmit HIV and other diseases.

It is also easy to neglect other potential risks, for example hairdressing and various cosmetic practices, tattooing and shaving. Care should be taken if equipment is shared. Equipment needs to be properly sterilized, no matter how long it is since it was last used. Even if HIV contamination is unlikely, there are lots of other diseases that can be spread the same way.

I don't expect to be able to wipe out the myth just by saying it is not true. But there is plenty of reading people can do to help figure out if it even makes much sense. My intention is not to increase stigma, rather to decrease it by loosening the connection between HIV transmission and unsafe sex in high prevalence African countries. Your skin protects you from HIV, but some processes are designed to go below the skin and others do so inadvertently.



Guantes DE Nitrilo said...
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Jeringas de insulina said...
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