Another option is to express Mtb antigens in the modified vaccinia virus Ankara (MVA) as a vaccine to boost subjects previously immunised with BCG [6].
This was a non-randomized, exploratory Phase I evaluation using a roll-over design and provided the first opportunity to boost subjects with rAd5 who had been primed in prior studies with DNA vaccines.
56 If a similar process unfolds as subjects ponder moral dilemmas, then enhancing serotonin function could boost subjects' responsiveness to the aversive Pavlovian cues present in the descriptions of the dilemmas, making them more averse to the suggested harmful action and more likely to disapprove of it.
Among the vaccinated boosted subjects who were anti-HBc positive at baseline, 12/17 (70.6%, 95% CI 44.0 89.7) showed an early anamnestic response, compared to 155/164 (94.5%, 95% CI 89.8 97.5) of boosted subjects who were anti-HBc negative at baseline(p<0.001).
In total, anti-HBs responses were evaluated at all three points (at baseline before boosting, two weeks and one year afterwards) in 168 of the boosted subjects.
On the other hand, of the 7 non-responders among the boosted subjects, two participants did show an effective response a year later.
Among the 16 vaccinated boosted subjects who were anti-HBc positive, 6 (37.5%, 95% CI 15.2 64.6) showed a long-term anamnestic response, compared to 131 out of the 181 (72.4%, 95% CI 65.2 78.7) of those who had remained anti-HBc negative (p = 0.001).
Among boosted subjects, the mean time between the onset of maintenance therapy and first booster was 147±92 days.
Prior to the booster dose, 85.3% (250/293) of DTPa-HBV-IPV/Hib primed and boosted subjects had persisting anti-HBs levels ≥ 10 mIU/mL.
The low number of contacts of active TB cases with boosting identified over three years (6%), the cost and the time consuming beyond the difficulty in distinguishing boosting from TST conversion in the second TST suggests that the strategy of two-step TST specifically among contacts of active pulmonary TB cases for identify boosting subjects may not be worthwhile.
