There's an important difference between HIV and smallpox. To eradicate smallpox, it suffices to vaccinate all the humans. But to eradicate HIV, you have to va

There's an important difference between HIV and smallpox. To eradicate smallpox, it suffices to vaccinate all the humans. But to eradicate HIV, you have to vaccinate all the apes. This family of viruses has already jumped species twice, so no doubt it will do so again.