In recent news, “A new vaccine designed to fight tuberculosis is less effective when given alongside shots for other diseases, a study has found, suggesting child immunization programs in developing countries may need a rethink,” states one article.
The vaccine in question is a tuberculosis vaccine called MVA85A. New data from clinical trials of the vaccine in babies in Gambia showed it was safe, but the immune response it prompted was lower in babies who got it with other infant immunizations than in those who got it on its own.
MVA85A is a vaccine designed to be given after Bacille Calmette-Guerin to boost the body’s immune response and improve protection against tuberculosis (TB). Originally developed by Dr. Helen McShane at the University of Oxford with funding from the Wellcome Trust and the Medical Research Council (MRC), it has already been shown to be safe and capable of eliciting powerful immune responses in clinical trials in adults in the UK, Gambia and South Africa. This is the first trial to evaluate safety of the vaccine in infants.
Martin Ota of the Medical Research Council Laboratories in Banjul, Gambia, who led the study, said the data should help doctors work out the best way to integrate the MVA85A into infant immunization programs in the future.
“We have a real opportunity to make sure that children are protected … against tuberculosis by introducing effective and well-timed immunization programs,” he said in a statement about the study. “This can only be achieved with robust information gathered from well-conducted clinical trials.”
This study, published in the journal Science Translational Medicine, was the first trial to evaluate the safety of the vaccine in babies. It involved 214 healthy four-month-old infants who had already received BCG at birth.
Standard childhood vaccinations are routinely given as part of a schedule known as the Expanded Program on Immunisation, EPI, which helps to improve vaccine coverage in the population by reducing the number of visits to the clinic required. The schedule includes vaccines for diphtheria, tetanus and whooping cough, as well as the current vaccine for TB, BCG. The aim is to vaccinate children in early infancy in order to protect them from disease as early as possible.
For the study, the children were given either EPI alone, MVA85A alone, or MVA85A with EPI, and their immune responses were monitored.
Overall, Ota’s team reported, MVA85A was deemed to be safe, well tolerated and induced a strong immune response. And importantly, the responses to the standard EPI vaccines were not affected by giving MVA85A at the same time. But the immune response prompted by MVA85A was lower in infants who received it with EPI vaccines, compared with those who got it alone.
“It’s reassuring to see that MVA85A does not affect immunity to the other vaccines,” said Helen McShane of Oxford University, who helped develop the new shot. But she said scientists would now need to find the best way to integrate MVA85A into infant immunization plans in future without limiting its effect.
Tuberculosis, TB, is currently a worldwide pandemic that kills around 1.7 million people a year. The infection is caused by the bacterium Mycobacterium tuberculosis and destroys patients’ lung tissue, causing them to cough up the bacteria, which then spread through the air and can be inhaled by others.
These findings may have important implications for designing the most effective immunization schedules for children, and also for the design of future clinical trials of the new vaccine.