Smallpox inoculation may slow HIV infection

According to a new study released on July 22, smallpox inoculation may offer some protection against primary HIV infection.

The study, released by BMC Immunology, looked into the clouded beginnings of HIV and theorized that there may have been some relationship to the end of smallpox and the beginning of HIV, since they occurred roughly in the same period.

Epidemiological analyses and computer modeling traced the origins of HIV to the early 1930s, but its exponential growth did not occur until the mid- to late-1950s, the same time that smallpox was eliminated and inoculations against smallpox stopped.

To test their hypothesis, the scientists took blood samples from those who had been vaccinated from smallpox and those who had not, then exposed them to HIV. Two specific strains were used, CCR5-tropic-HIV-1 and CXCR4-tropic-HIV-1.

The blood cells that had been immunized against smallpox showed up to a five-fold decrease of viral replication of CCR5 when compared to the unvaccinated. There was no change in the progress of CXCR4 in the samples.

This led the scientists to conclude that smallpox vaccinated individuals may be afforded increased protection against both contracting HIV and slowing its progression, assuming the strain they come in contact with is CCR5. CCR5 is most often the cause of HIV-1.