Dengue vaccine provides ample protection to children

The dengue vaccine confers substantial protective benefit on children aged 10 to 15 years, reports a study in the Philippines, which was presented at the recent ESPID 2023.

A higher population analysis with the necessary laboratories can help validate the robustness of this finding, according to the researchers, led by Christine Marie San Pedro, Department of Pediatrics, Bataan General Hospital and Medical Center, Balanga City, Philippines.

San Pedro and her team conducted a retrospective cohort study of the clinical course and outcome in confirmed paediatric dengue patients with and without dengue vaccine between January 2018 and December 2019 in a tertiary hospital. They used statistical tools to analyse clinical records.

Of the 239 children (mean age 12.5 years) who were enrolled in the study, 62 received the dengue vaccine and 177 did not. Three doses were administered to the vaccinated. Previous infection occurred in 18.8 percent of the participants. [ESPID 2023, abstract PV0145]

No significant difference was observed among 197 dengue patients with warning signs, while the remaining 42 children had severe disease. On the other hand, a statistical difference was seen among nonvaccinated patients who had anorexia and abdominal pain. Among those who received the vaccine, joint pains and narrow pulse pressure were common.

Notably, nonvaccinated patients were nonstructural protein 1 (NS1)-positive and more likely to be leukopenic and thrombocytopenic upon admission. However, vaccinated children were found to be positive to immunoglobulin (Ig)M and IgG.

None of the vaccinated patients succumbed to dengue, while 1.3 percent of the nonvaccinated group died. In addition, nonvaccinated children stayed much longer in the hospital, which reached statistical significance. No significant between-group difference was noted in terms of management and outcomes.

“Dengue is the leading cause of childhood morbidity and mortality globally more than any other vector-borne viral disease,” the researchers said. “In 2016, dengue vaccine was introduced in a school-based immunization program in the Philippines [but] was discontinued after nearly 3 years.”

DENV1-4 IgG ELISA

In another study presented at ESPID 2023, a group of investigators sought to determine prior dengue serostatus among children receiving the dengue vaccine (Dengvaxia) in the Philippines by an NS1-based enzyme-linked immunosorbent assay (ELISA).

“Our DENV1-4 (dengue virus serotypes 1 to 4) NS1 IgG ELISA and the algorithms developed can determine prior DENV serostatus among Dengvaxia recipients during both DENV breakthrough infection and nondengue period to assess the long-term safety and effectiveness of Dengvaxia in the real world,” the investigators said.

The sensitivity and the specificity of the DENV1-4 IgG ELISA were 97.0 percent and 99.4 percent, respectively. This tool could determine prior DENV serostatus among vaccine recipients (n=100) with or without acute dengue for up to 30 months after vaccination. [ESPID 2023, abstract PV0195]

The investigators assessed the performance of the DENV1-4 IgG ELISA using well-documented control samples (n=371) of various flavivirus infections, including those >20 years after DENV infection, from the fever surveillance program in the Philippines.