Thaindian News

Washington, May 18 (IANS) The end of smallpox vaccination in the mid-20th century may have contributed to the rapid spread of HIV, a new study says.
Smallpox immunisation was gradually withdrawn from the 1950s to the 1970s following the worldwide eradication of the disease, and HIV has been spreading since about the same time period.

Researchers looked at the ability of white blood cells taken from people recently immunised with vaccinia (cowpox virus used to vaccinate against smallpox) to support HIV replication.

They found significantly lower HIV replication in blood cells from such individuals.

Raymond Weinstein, lab scientist at the George Mason University, said: “There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the reuse of unsterilised needles and the contamination of early batches of polio vaccine.”

“However, all of these have been either disproved or do not sufficiently explain the behaviour of the HIV pandemic.”

“Our finding that prior immunisation with vaccinia virus may provide an individual with some degree of protection to subsequent HIV infection suggests that the withdrawal of such vaccination may be a partial explanation,” said Weinstein.

Weinstein worked with a team from George Washington University and University of California at Los Angeles (UCLA).

Weinstein and his colleagues propose that vaccination may confer protection against HIV by producing long-term alterations in the immune system, said a George Mason release.

These findings were published in BMC Immunology.