(Reuters) – The World Health Organization said on Monday it hopes to review safety data on Sanofi’s dengue vaccine this month, while the Philippines ordered an investigation of its now suspended massive immunization program after the French drugmaker said it could actually worsen the disease in some cases.
The safety fears involve possible increased risk to people who had not previously been exposed to the dengue virus prior to vaccination with Dengvaxia.
Sanofi SA attempted to allay concerns, saying in a statement that “the vast majority of those vaccinated to date live in high endemic settings and, therefore, will have had a prior dengue infection before vaccination.”
Dengvaxia, the first approved Dengue vaccine, had been forecast by Sanofi to eventually bring in nearly $1 billion in annual sales. But even recent more modest analysts’ sales forecasts are now looking unattainable given the safety issue and clinical evidence revealing unequal protection against different strains of dengue.
The vaccine so far has been approved in 19 countries and launched in 11, Sanofi said. Most sales have come from the Philippines through its government immunization program involving more than 730,000 children, and Brazil, where the state of Parana has seen a three-fold increase in dengue in the past few years.
Dengue is a mosquito-borne tropical disease that kills about 20,000 people a year and infects hundreds of millions.
The WHO, which issued a report identifying the vaccine’s safety risk in mid-2016, recommended it only be used in people who had prior dengue infection.
Brazil confirmed it already had recommended restricting use of the vaccine to those previously infected with dengue but had not suspended it entirely.
Brazilian health regulator Anvisa, in an emailed statement to Reuters, said it had not received any reports of vaccine recipients dying or falling more severely ill because of the drug. It does not know how many people have received the vaccine in Brazil since its 2015 approval.
Sanofi, whose shares rose 0.4 percent in Paris on Monday, explained its “new findings” of increased risk at a news conference in Manila. It did not say why action was not taken when the WHO raised the issue last year.
The Philippines Department of Health halted use of Dengvaxia last week after Sanofi…