Single dengue vaccine dose shows mixed results: Protection hinges on prior exposure

  

In a recent study published in the journal The Lancet Infectious Diseases, researchers conducted a prospective, longitudinal, population-based cohort study in two communities in the Philippines to investigate the effects of the prematurely discontinued CYD-TDV vaccine on children's susceptibility to the dengue virus (DENV). While the first of three required doses of the vaccine was publicly administered in 2016 by the Philippine Department of Health, phase three CYD-TDV outcomes resulted in the vaccination program being discontinued.

 

The present study reveals that the single administered dose of CYD-TDV was incapable of conferring protection against virologically confirmed dengue among patients without a prior history of DENV infection (zero or one prior infection). In stark contrast, young patients who had been exposed to two or more prior DENV infections were found to have substantially reduced DENV infection risk following the first CYD-TDV vaccine dose. This protection was found to be long-lasting, with the observed risk reduction persisting throughout the first three years and the subsequent follow-up period.

The dengue virus and the need for this study

Dengue (DENV) is a mosquito-borne viral disease prevalent worldwide in tropical and subtropical regions, particularly in rural and underdeveloped communities. It can be caused by any of four closely related viruses (serotypes), given that repeat infections are surprisingly common. Disease severity can range from asymptomatic or mild to life-threatening, with common symptoms including high fever, persistent headaches, rashes, and characteristic muscle and joint pain.

 

Despite years of research, dengue remains without a specific cure, with clinical interventions involving management of the fever and patient discomfort and pharmacotherapy restricted to common anti-viral drugs. Thankfully, numerous dengue vaccines have been developed and proven effective against the disease, saving countless lives, especially in recent decades. One of these vaccines developed in France in 2015 was the CYD-TDV vaccine, targeted at children and adolescents.

 

To learn more about the related topics being discussed at the Vaccine Congress 2024, you can join the conference.

 

For info: https://vaccines.annualcongress.com/