Operation Smallpox Zero was launched in India in 1975 and was certified globally eradicated on December 9, 1979. But relief over the first success story of modern medicine was short-lived. The experts of the immunization drive did not know that another virus, lurking in the African forests, was as keen for smallpox to clear out as they were. It came to light in the 1980s as HIV and is still counting its victims.
The period that marked the eradication of smallpox and merged into the rapid spread of AIDS had caught Weinstein's eye but he couldn't ignore a protein called CCR, essential to both the viruses.
"CCR5 and CXCR4 are two receptors on cell surfaces that help immune cells go to infection sites. HIV uses them to invade cells as a part of its life-cycle," said Michael, geneticist from the University of California at Los Angeles. "Some European people have a mutated ccr5 gene which makes them HIV-resistant," said Michael Bukrinsky, vice-chair of microbiology, immunology, tropical medicine at George Washington University in usa. How does the study explain HIV-positive people who also received the smallpox vaccine? "In our case, it is the innate immunity induced by the vaccine that conferred protection but it is short-lived usually. So it was exciting to see protection even a year later," said Bukrinsky. Virologist T Jacob John, however, thinks the link made by the study is a mere speculation. The doctor from the the Christian Medical College in Vellore, said: "Imagine the smallpox vaccine continuing into the 1980s and thereafter, it would have been impossible to control the spreading of both the fatal diseases."