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Experimental HIV vaccine gives protection against more than one strain of AIDS-causing virus

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A Human Immuno-deficiency Virus (HIV) vaccine has shown ‘surprisingly strong’ effects in a trial on people living in South Africa.

The jab was trialed on a group of 100 people after an early study of it by the United States (U.S.) Army in Thailand produced ‘modest results’.

In this trial, people’s bodies produced significantly higher numbers of immune cells, which the body uses to fight off the Acquired Immune Deficiency Syndrome (AIDS)-causing virus.

Their bodies were believed to be able to fend off HIV with a success rate of more than 31 per cent. However, none of the volunteers already had the virus. And the immunisation appeared to protect people from more than one strain of HIV, suggesting it may be possible to create a universal vaccine.

The research was published in the journal Science Translational Medicine.

Researchers from the HIV Vaccine Trials Network in Seattle, Washington, led the study. They gave the jab, named RV144, to people with an average age of 21 and then measured how their immune systems responded.

White blood cells called CD4+T cells, which the body uses to fight off HIV, rose significantly in all the participants, regardless of their age or sex. And scientists also saw people developed HIV antibodies – immune system proteins matched specifically to the virus – after they were vaccinated. When they compared the results to the earlier tests on Thai patients the researchers were surprised to find the vaccine had worked even better on the South Africans. Both groups of people developed immune protection against multiple strains of the HIV virus – strains named AE, B and C by the scientists. Dr. Larry Corey, the lead investigator, said: “These breaks open the thought pattern that each region of the world needs a separate type of HIV vaccine based upon their circulating strains.”

The C strain was the main target for the team in South Africa because that’s the form of the virus most prevalent on the continent.

In their study, Corey’s team said: “In general, cross-[strain] immune responses were stronger than expected in South Africa”.

An estimated 1.8 million people were diagnosed with HIV last year in spite of surging global efforts to stop the spread of the virus. Although there are now medications, which can suppress the virus to levels so low it does not affect patients or spread to others through sex, these are not always available in poorer countries. Therefore, the quest for a vaccine is a continuing and urgent one – ‘a global imperative’, according to the team from Seattle. The earlier trial of HV144 on Thai people protected patients with a 31.2 per cent success rate against the HIV virus.

And another lead investigator, Dr. Glenda Gray, said: “Vaccine-induced immune responses elicited from this [strain] B/E based vaccine regimen induced cross-[strain] responses in South Africans and, at peak [protection], the South African vaccinees exhibited significantly higher cellular and antibody immune responses than the Thai vaccines.”


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