Fig 1.
PRISMA flow diagram highlighting selection process for studies.
Table 1.
Summary of study characteristics and attack rate.
Fig 2.
Positive correlation between peak viremia and frequency of fever.
Blue circles represent mean peak viremia levels in participants challenged with serial passage attenuated strains, and orange squares represent Δ30 strains. In studies where mean peak viremia was not reported, the highest peak viral load reported is used. Two studies did not report viral loads and is not represented in this graph. Three studies reported peak viremia in Genome equivalent (GE)/ml whilst six reported in Plaque forming unit (PFU)/ml.
Fig 3.
a. Symptoms of dengue fever elicited by dengue challenge strains in seronegative participants.
SPA DENV-2 and DENV- 4 strains were not included as there were less than 10 participants who were challenged with these strains. Fever, headache and myalgia were more commonly observed after SPA challenge, whilst rash was frequently observed with Δ30 challenge. Chi-square test was performed to assess difference in frequency of symptoms amongst various challenge strains. * = p < 0·05, ** p < 0·01. b. Biochemical abnormalities elicited by dengue challenge strains in seronegative participants. Serial passage attenuated (SPA) DENV-2 and DENV-4 strains were not included as there were less than 10 participants who were challenged with these strains. Other biochemical abnormalities (e.g., leucopenia) are not shown as they were inconsistently reported in the studies. ▴Neutropenia was only reported amongst 4 out of the 29 participants challenged with SPA DENV-1 strain and may not be fully representative of all the participants. Thrombocytopenia was defined as platelet count <100 x 109/L, neutropenia was defined as absolute neutrophil count <1 x 109/L. Chi-square test or Fisher’s exact test was performed to assess difference in laboratory abnormalities amongst various challenge strains. * = p < 0·05, ** = p< 0·01.
Table 2.
Frequency of symptoms and biochemical abnormalities post dengue challenge amongst previously vaccinated participants and unvaccinated controls.
Fig 4.
Factors affecting response to DCHIM.
Created in BioRender. Ong, C. (2026) https://BioRender.com/12yy4iq.