(3) Type C (primitive variant): this variant drains mainly to the dural sinuses, not via the vein of Galen (i.e., the perimesencephalic veins drain into the superior petrosal sinus or the BVR drains directly into the transverse or straight sinus).
The development of BVR type in each group was compared with an aSAH control group to help elucidate the source of bleeding.
Interestingly, our study revealed that there was also a significant difference in the unilateral BVR type between the nPMN-SAH and aSAH groups (p = 0.021).
TABLE 5: Type of BVR in nonaneurysmal subarachnoid hemorrhage and aneurysmal subarachnoid hemorrhage patients.
But high compliance to a vaccination campaign cannot be expected in regions with low BVRs associated with religious or philosophical beliefs that are opposed to vaccination.
We also showed that BVRs that are high (>80%) but not high enough to achieve herd immunity ([approximately equal to] 95%) keep the number of susceptible persons low, reduce the size of an outbreak, and reduce the speed at which the disease spreads, thereby increasing the time frame for mounting an effective intervention.
In these settings, because of the high baseline vaccination ratio (BVR), a shift in age distribution of measles cases toward older nonvaccinated school children is often noted (19).
The percentage of vaccinated persons at the beginning of the outbreak was determined by the BVR, and we assumed that vaccination-acquired protection does not wane with time.
Assuming a BVR of 91.3%, calculated by Wichmann et al.
(5) used a Bayesian method to estimate the BVR at 94.3%.