Can casual contacts transmit HIV?

HIV cannot reproduce outside the human body. Therefore, casual contacts like shaking hands, kissing, sharing toilets and drinking fountains, eating together, going to school together or working together cannot transmit HIV.

Saliva
Up to now, HIV infection caused by saliva, tears, sweat, urine or feces has not been reported. While these body fluids of the infected can have the virus, the amount is not enough to cause infection. To cause infection, it will require at least two litres of these fluids with the virus entering the body at one time.

Mosquito bites
Mosquito bites cannot pass on HIV as the virus cannot live inside the body of a mosquito. Mosquitoes will digest the blood they sucked and will not spit it out. Even if the mouth part of a mosquito has some infected blood, the quantity is too small to cause infection.

Blood donation
Donating blood to the Hong Kong Red Cross will not get infected with the virus since all needles used are new and will only be used once.