Dengvaxia<sup>®</sup>: Protective value for people with at least one prior dengue infection confirmed; vaccinating people without prior infection not recommended

The New England Journal of Medicine published the article Impact of Dengue Serostatus on Dengue Vaccine Safety and Efficacy for online access on 13th June 2018. This article includes a full analysis of the long-term clinical data on our vaccine against dengue that we shared in a public announcement last November.

This new publication confirms the vaccine’s potential to prevent dengue, particularly severe dengue (84%) and hospitalizations due to dengue (80%) for the 5-year follow-up period of the study in individuals 9 years of age or older who have had a prior dengue infection. This finding has also been fully documented and recognized by different experts including the WHO’s Strategic Advisory Group of Experts on Immunization in their latest recommendation on the use of the vaccine which was published in their Weekly Epidemiological Report on 8th June 2018.

Dengue is the fastest growing mosquito borne disease in the world today with an estimated 1 million new infections reported daily. While severe dengue is rare overall, occurring in only 0.5% of all symptomatic cases of the disease, secondary infections with the virus are more likely than first infections to develop into severe disease. This unique feature of dengue infection is critical to understanding the new data on the dengue vaccine discussed in the New England Journal of Medicine article. In this supplementary analysis, we found an increased incidence of severe disease in vaccinated people without a prior infection compared to un-vaccinated people without a prior infection.

The relative risk of getting severe dengue from a mosquito bite post-vaccination for a study participant 9 years of age or older who had no prior infection was similar to that seen in an unvaccinated person who gets a secondary infection. More importantly, the degree of severity of the disease in vaccinated individuals responded well to medical care and all individuals recovered fully.
Based on this finding, reported in November 2017, Sanofi Pasteur has reached out to the national regulatory authorities in the countries where the vaccine is currently approved to propose an update to the prescribing information for the vaccine recommending use in individuals with prior dengue infection and warning against vaccination of those without prior infection. At present, several countries have already decided to move forward with the proposed label update and the rest are still reviewing it.

In sharing the new data on our dengue vaccine, Sanofi Pasteur has realized the increasing importance of being able to communicate complex science in an understandable way to avoid unnecessary anxiety and correct any misunderstanding in the public about the safety or efficacy of our vaccines.

Sanofi Pasteur has a long-standing commitment to the global fight against dengue. We will make every effort to facilitate access to the dengue vaccine for people who have had at least one dengue infection already and could, therefore, benefit significantly from the vaccine’s high degree of protection against subsequent infections with dengue.