Tetravalent TV003 vaccine safe, immunogenic for Flavivirus-exposed patients
The TV003 tetravalent dengue vaccine is well-tolerated and produces a strong antibody and immune response in patients who have previously been exposed to other Flaviviruses, a new randomized controlled trial has shown.
Investigators randomized 58 participants (median age 30 [20 to 50] years; 46 percent male) to receive either placebo (n=17) or the TV003 vaccine (n=41).
The vaccine was well-tolerated. Between the two groups, only cases of rashes were significantly more common in the vaccine group (66 vs 6 percent; p<0.001), 81 percent of which were mild and 18.5 percent were moderate.
One patient suffered from two serious adverse events: syncope 51 days after vaccination and a transient ischaemic attack 77 days after vaccination. Both were determined to be unrelated to the vaccine.
There were no significant differences in the occurrence of erythema, pain, tenderness, fevers, headaches, retro-orbital pain and myalgia (p=1.00 for all) between the groups.
In terms of serological response, one dose of the TV003 vaccine prompted an 87 percent antibody response rate to all four dengue serotypes. Viremia was achieved in 76 percent of the participants.
The second TV003 dose did not yield significant viremia or spikes in antibody titers, suggesting that one dose is enough to protect against dengue. The mean peak titers ranged from 0.86 to 1.1 log10 PFU/mL.
The tetravalent TV003 vaccine candidate was designed to protect against all four dengue serotypes. The vaccine was administered at 0.5-mL doses subcutaneously. Clinical assessments were performed every other day for the first 16 days, and on days 21, 28, 56 and 90. A second vaccine or placebo dose was administered on day 180.