Brief Answer:
Information

Detailed Answer:
Hello and welcome,

The risk is present but extremely low. If your niece is not teething, it would be unlikely for there to be blood on the syringe and if she has no bleeding there is no risk as saliva alone cannot transmit it. There have been extremely rare cases of contracting HIV in someone eating food that has been pre-chewed by an HIV-infected person. The contamination occurred when infected blood from the caregiver’s mouth mixed with food while chewing. Again, this is extremely rare.

If the syringe was not used for a matter of minutes, it is also unlikely to transfer the virus as the virus is rather fragile and only lives on inanimate objects for a matter of a few minutes.

HIV can live in dried blood for up to 6 days, but that doesn't mean it can be transmitted as the number of viruses that are strong enough once a transmissible body fluid has dried would be very low.

There has to be enough virus to be transferred to cause infection.

Do you know the HIV titer of your niece? Because people can be HIV+ but no longer infectious because of treatment. They just don't have enough virus circulating to pass on to others.

The presence of HIV in spilled or discarded body fluids does not necessarily mean that it has the potential to infect. While the conditions may be suitable for HIV to survive in microscopic quantities, transmission requires significant quantities of HIV. In general, saliva is not considered a transmissible source because the level of virus is saliva, sweat, and tears is considered insufficient for infection.

Even in instances where a person has come into contact with a discarded syringe—considered to be of potentially higher risk—most research has suggested that the risk of transmission was next to zero. An extensive review conducted in Australia in 2003 reported not one case of HIV or hepatitis C as a result of contact with a discarded needle.

Outside of the body, HIV does not do well at room temperature (68oF), with the virus' survival decreasing significantly as it reaches body temperature (98.6oF) and beyond.

There is no definitive line by which to say how much body fluid or how big of a wound is needed for an HIV infection to occur.

So - in my opinion as a family medicine doctor there is not much chance of your baby getting HIV from this incident, and no chance if your niece was not actively bleeding, if the syringe was left out for a few minutes between use, or if your niece's HIV titer is low.

If you would like additional opinions, consider calling the University of San Francisco post-exposure hotline which should still be open now:

Phone Consultation

(888) 448-4911
9 a.m. – 9 p.m. EST,
Seven days a week

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