And, it found just a single dose of the vaccine offered considerable protection. Three weeks after being given a single dose of the vaccine it had an efficacy rate of 76 per cent and measurements over a 90 day period showed the efficacy rate did not wane. "Vaccination programs aimed at vaccinating a large proportion of the population with a single dose, with a second dose given after a 3 month period is an effective strategy for reducing disease, and may be the optimal for rollout of a pandemic vaccine when supplies are limited in the short term," the study authors said.
The trial also confirmed the vaccine was 100 per cent effective in protecting against severe disease, hospitalisation and death.