According to a new research, the vaccination with the smallpox vaccine called "vaccinia" may increase an individual’s ability to resist infection with HIV. The late 20th-century spread of HIV can be linked to the simultaneous vanquishing of smallpox disease, according to the new finding.

The researchers at the University of California, Los Angeles, and George Mason University in Manassas, Va worked on this recently and got their findings published in BMC Immunology on May 17.

Dr. Raymond Weinstein of George Mason U. said, “There have been several proposed explanations for the rapid spread of HIV in Africa. These include wars, the reuse of unsterilized needles and the contamination of early batches of polio vaccine”.

He further shared that these proposed explanations have been either disproved or do not adequately explain the behavior of the HIV pandemic. The vaccine for smallpox was gradually removed from use between the 1950s and the 1970s, which wiped out the disease globally.

Weinstein and his colleagues studied the behavior of white blood cells sampled from patients, who were recently immunized with the smallpox vaccine, in order to get a closer look at how the two occurrences might be connected.

The cells from immunized individuals were five times less expected to allow for HIV replication after exposure to HIV, as compared to the same cells taken from non-immunized patients.