Dengue

Pregnancy: CONTRAINDICATED — live vaccines.

Both Dengvaxia (CYD-TDV) and Qdenga (TAK-003) are live attenuated vaccines and are contraindicated during pregnancy.

• Post-vaccination: avoid conception for 1 month after the last dose.

• Inadvertent vaccination during pregnancy: monitor pregnancy, but no indication for termination.

• Animal reproductive toxicity studies are limited. Theoretical risk of fetal infection with live vaccine virus.

Breastfeeding: Not recommended.

Both Dengvaxia and Qdenga are live attenuated vaccines. Safety during breastfeeding has not been established. Defer vaccination until after cessation of breastfeeding when possible. If vaccination is essential, discuss risk-benefit with the patient.

Pediatric use:

• Dengvaxia (CYD-TDV): Licensed for individuals 6–45 years with confirmed prior dengue infection (seropositive). CRITICAL: Must NOT be given to seronegative individuals — increased risk of severe dengue through antibody-dependent enhancement (ADE).

• Qdenga (TAK-003): Licensed from 4 years of age. Does not require pre-vaccination serostatus testing (EU/UK approval).

• Pre-vaccination screening (Dengvaxia only): rapid NS1 antigen or anti-dengue IgG required.

• 2–3 dose schedules depending on product (see administration_info).

Geriatric use:

• Dengvaxia: licensed up to 45 years of age. Not recommended for ≥46 years (limited data).

• Qdenga: no upper age limit specified in EU label, but clinical trial data are limited in ≥60 years.

• Dengue in elderly patients may be more severe. Vaccination benefit should be weighed against limited efficacy data in this age group.