A team of Johns Hopkins researchers working with animals has developed a vaccine that prevents the virulent tuberculosis bacterium from invading the brain and causing a highly lethal condition known as TB meningitis, a disease that disproportionately occurs in TB-infected children and in adults with compromised immune systems.
Tuberculosis brain infections often cause serious brain damage or death, even when recognized and treated promptly, researchers say. Many drugs currently used to treat resistant TB strains cannot cross the brain-blood barrier, which stops pathogens from entering the brain, but also keeps most medicines out of the brain's reach.
The new Johns Hopkins vaccine, tested in guinea pigs, could eventually add a much-needed weapon to a largely depleted therapeutic and preventive arsenal. TB currently affects nearly nine million people worldwide and is growing increasingly resistant to antibiotics, according to the World Health Organization. A report on the research was published online today in the journal PLOS ONE.
"Once TB infects the brain, our treatment options have modest effect at best, so preventing brain infection in the first place is the only foolproof way to avert neurologic damage and death," said lead investigator Sanjay Jain, an infectious disease specialist at the Johns Hopkins Children's Center. "Unfortunately, our sole preventive weapon, the traditional BCG vaccine, has a spotty track record in terms of efficacy."
If proven effective in people, the vaccine could be used to boost the brain-protective effects of the traditional BCG vaccine, the only currently available anti-TB vaccine, the efficacy of which varies greatly, Jain says. BCG contains live bacteria and therefore cannot be given to immune-compromised people, such as HIV patients, who are at greater risk of developing widespread TB. About one-third of the 34 million HIV-infected people worldwide have TB, according to the WHO.
Source: Johns Hopkins University