TABLE 2.

Immunogenicity of rDEN4Δ30-4995 despite its enhanced attenuation phenotype^*

Vaccine candidate (105 PFU)	% of volunteers with viremia	Mean ± SE peak virus titer (log10 PFU/mL serum)†	% Seroconversion‡	Reciprocal geometric mean serum neutralizing antibody titer (range) at day 42§
rDEN430-4995	0	< 0.5	95¶	52 (7–715)
rDEN4Δ30#	70	1.6 ± 0.1	100	156 (23–772)
rDEN4Δ30-200,201**	0	< 0.5	100	84 (9–382)

^*PFU = plaque-forming units.

^†Calculated for viremic volunteers only. The lower limit of detection is 10^0.5 PFU/mL.

^‡Defined as a ≥ 4-fold rise increase in serum 60% plaque reduction neutralizing antibody titer (PRNT₆₀) to dengue virus type 4 (DENV4) on day 28 or day 42.

^§PRNT₆₀ was < 10 for all volunteers on study day 0. For direct comparison of reciprocal geometric mean titers, day 42 serum samples from vaccinees receiving either rDEN4Δ30-4995, rDEN4Δ30-200,201, or rDEN4Δ30 were evaluated in a single assay.

^¶The only volunteer who failed to seroconvert to DENV4 had clinical influenza and shed influenza B virus during days 10–17.

^#Historical data.²⁵

^**Historical data.³¹