The world's only vaccine against dengue has hit an obstacle, and this complication is causing some countries to restrict the use of the vaccine.
Sanofi Pasteur, the French company that makes the shot, raised new safety concerns last week about the vaccine. In response, the Philippines suspended a massive immunization campaign, which has already given a dose of the vaccine to more than 700,000 children. And the Brazilian government has tightened the restrictions on the shot.
The vaccine, called Dengvaxia, increases the risk of a deadly form of dengue for people who have never been exposed to the virus, Sanofi Pasteur wrote in a statement on Wednesday. The company says it discovered the complication after analyzing data from a six-year study.
"For those who had not previously been infected with the dengue virus … the analysis found that in the long term, more cases of serious illness could occur after vaccination after a subsequent dengue infection," he said. the company in a press release.
Dengue usually causes a mild illness with flu-like symptoms. But in about 5 percent of cases, the disease can be life-threatening, with the possibility of internal bleeding and organ failure. Dengue sickens hundreds of millions of people and kills more than 20,000 each year.
This severe form of dengue is one of the leading causes of death among children in some parts of Asia and Latin America, says the World Health Organization.
As far as we know, as far as we know, there are no reports of deaths related to dengue vaccination, "Ruby Dizon, medical director of Sanofi Pasteur Philippines, told Reuters.
Previous studies found Dengvaxia is approximately 60 percent Effective for children living in countries where dengue is common, these findings are still standing, says the company.
But the new safety warning is particularly worrisome for young children because they are less likely to have been exposed to dengue. before receiving the vaccine.
Sanofi Pasteur has not revealed how much the vaccine increases the risk of severe dengue, but a clinical trial, published in 2015, offers clues about the size of the effect. 9 years, the vaccine increased the risk of hospitalization, after contracting dengue, by approximately 50 percent, on the contrary, the vaccine reduces The risk of hospitalization is almost half in older children.
In response to the new safety warning, WHO is reviewing its guidelines for the vaccine and temporarily recommends that the vaccine be given to people only if they know they have had previous infections.
Sanofi Pasteur has spent more than $ 1.5 billion to develop Dengvaxia in the last two decades. The vaccine is currently approved in 19 countries, including Costa Rica, El Salvador, Guatemala, Indonesia, Mexico and Thailand.
The Philippines led the most ambitious and costly effort to vaccinate children. More than 700,000 children, over 9 years old, had already received a dose. In the following years, the country had planned to administer two more doses to the 700,000 children who had already received a dose.
Copyright NPR 2017.