Tag: vaccine (page 2 of 2)

a new tuberculosis vaccine falls short

tuberculosis

Tuberculosis bacteria

A new study of the potential tuberculosis vaccine, modified Vaccinia Ankara virus expressing antigen 85A (MVA85A), has failed in a study of 3000 infants in South Africa. Scientists had hoped it would help improve protection against the infection when used with the current vaccination (BCG). The study was a double-blind, randomised, placebo-controlled trial of healthy infants (aged 4—6 months). The infants were randomly administered BCG with either MVA85A or a placebo of Candida skin test antigen then examined every 3 months for up to 3 years. During the course of the trial, the rates of serious or systemic infection from tuberculosis were similar for the group that received the new vaccine enhancer compared to those given the placebo. The researchers did note that the MVA85A does appear to be safe and that no adverse effects were cause by the antigen itself. This was the first efficacy trial of a tuberculosis vaccine in infants in more than 45 years. More details here at The Lancet [subscription required].

hiv antibodies

Schematic diagram of an HIV virus and it’s coat glycoprotein bound to an antibody. Image from Corpus Christi College Oxford.

A South African study offers hope that an HIV vaccine can be developed. Certain changes in the virus’ coat proteins appear to trigger a more robust production of antibodies. From NPR news:

One of the women had neutralized 88 percent of 225 HIV virus subtypes after three years with the virus, while the other woman had neutralized 46 percent of 41 subtypes after two years of infection.

The researchers found that a specific change in the coating of the HIV virus appeared to be the trigger for the women to produce antibodies that could thwart its entry into cells.

One reason the HIV virus has proven so difficult to fight is that it is skilled at hiding from antibodies that can block the virus from attacking cells. But researchers believe that the more they understand how the antibodies develop, the better chance they have at developing an HIV vaccine.
 

The original research paper appears in Nature magazine.

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