In a study initiated by the Norwegian Institute of Public Health, together with Epicentre (the research arm of Doctors Without Borders/Médecins Sans Frontières), and Mbarara University of Science and Technology in Uganda, immune responses in patients receiving smaller doses of a meningitis vaccine were found to be comparable to a full dose.
Scientists conducted a randomized clinical trial of 750 healthy volunteers (2-19 years old) in Uganda in 2004.
Their immune response, assessed by serum bactericidal activity (SBA), was measured for 1/5 and 1/10 doses compared to a full dose. SBA response and safety/tolerability using 1/5 dose were comparable to a full dose for three serogroups (A, Y, W135), but not a fourth (C).
Keeping in mind the current shortage of meningococcal vaccines for Africa, the use of 1/5 fractional doses should be considered as an alternative in mass vaccination campaigns.
The study's findings were used for a 2007 WHO recommendation that a fractional dosing strategy be utilized in the event of severe vaccine shortages during a meningitis epidemic.
The results have now been published in PLoS Neglected Tropical Diseases.