International study confirms higher risk of dengue in children who got Sanofi vaccine - The Daily Sentry

Thursday, June 14, 2018

International study confirms higher risk of dengue in children who got Sanofi vaccine

A data analysis findings on Sanofi’s dengue vaccine has just been published on Wednesday by New England Journal of Medicine (NEJM) that gives fresh support to the recommendation of the World Health Organization last April, that the vaccine should not be used without testing for prior dengue exposure.

If recalled, Sanofi’s dengue vaccine has been given and administered to more than 8, 000 school children in the Philippines.

The analysis confirms that the said vaccine increases risk of hospitalization and causes severe dengue in those who never had dengue fever before.

In November last year, Sanofi warns that its vaccine could increase the risk of severe dengue based on a new analysis of blood samples from thousands of its receivers. This newly developed tests reportedly allowed the company to determine which children had been previously infected.

The study authors estimated that if given to 1 million children over 9 years old, the vaccine could prevent around 11,000 hospitalizations and 2,500 cases of severe dengue cases. However, it could also result to 1,000 hospitalizations and severe 500 cases of dengue in children who were not previously infected.

“With the new data, we now know what is the best way to utilize the dengue vaccine,” Dr. Su-Peing Ng said, from global medical head of Sanofi’s vaccines unit.

“In a natural dengue infection, the first exposure to one of four strains of the virus is typically mild. But a second exposure to a different virus type can result in severe disease.

Experts have long been concerned that a dengue vaccine that is only partially protective could work the same way, increasing the risk of severe disease requiring hospitalization with exposure to a second strain.” Says Reuters report.*

Further, the analysis conducted by NEJM includes data on 2, 384 vaccinated children and 1, 194 who were not, bears it out.

“Our findings support the hypothesis that in the absence of previous dengue exposure, the (Sanofi) vaccine partially mimics primary infection and increases the risk of severe dengue,” the study authors wrote.

Reuterr’s report also explained that “among previously uninfected children who received the vaccine, there was a significantly higher risk of hospitalization among those aged 2-8, and a trend toward increased hospitalization in those aged 9-16, the study found.”

Meanwhile, the previously exposed ages 9 and older children, the vaccine has reduced the rates of severe diseases and hospitalization by 80 percent compared to the control group.

Sanofi’s clinical trials, on the other hand, with children ages 2-5 years old did show an increased risk of hospitalization three years after the vaccine was administered. However, it was unclear whether the result was due to an immature immune system or an issue with the vaccine.

Although there were no good tests for prior to infection of dengue, current tests can detect acute infection – which can be a helpful information in identifying children who might benefit from Sanofi’s dengue vaccine.

According to Dr. Ng, Sanofi is negotiating already with several countries on how to use the vaccines with existing tests.

Sanofi earlier advised that it is working on a rapid test for prior dengue exposure.

 Source: Reuters