The Philippines suspended a dengue fever vaccine that was given to thousands of children and launched an investigation, after the drug's manufacturer said new evidence showed it could worsen symptoms in some cases.
The tropical country last year became the first nation to widely distribute the vaccine, branded Dengvaxia, after a fast-track approval process. The government says more than 730,000 people, mostly children older than nine, were given the vaccine, manufactured by the vaccinations division of French pharma giant Sanofi SA.
A person can be infected by dengue as many as four times due to the existence of different strains. Subsequent infections are often more severe.
Sanofi said last week new data found the vaccine was effective for people who had already had dengue, but for those who hadn't, "more cases of severe disease could occur following vaccination." The company said it had asked regulators to change the vaccine label to recommend that people don't take the vaccine if they haven't been infected previously.
It isn't the first time warnings have surfaced about the vaccine. In a July 2016 report, the World Health Organization noted that the vaccination "may be ineffective or may theoretically increase the future risk of hospitalized or severe dengue illness" in those who have not had dengue at the time of vaccination.
The WHO's Strategic Advisory Group of Experts will meet before the end of the year to review data on Sanofi's dengue vaccine, a WHO spokesman said Monday. WHO reiterated its Nov. 30 recommendation that "as a precautionary and interim measure", Dengvaxia only be given to people known to have already been infected with dengue.
Philippines presidential spokesman Harry Roque said Sunday that Manila vowed to "leave no stone unturned" in making accountable those responsible "for this shameless public health scam."
On Monday, however, the government said it had a record of all the children who had received the vaccine and would monitor them for five years for signs of the disease. It played down the impact of the new findings, noting that the threat of a severe dengue contraction was a risk only for those who had not had dengue before, but had been given the vaccine.
The government last week suspended its vaccination program. Though no deaths or cases of severe dengue have been definitively linked to the vaccine, some politicians have pointed to cases of children who have died since receiving it. "This is our most urgent task. Laxity is not an option. We are racing against time," said opposition Senator Risa Hontiveros.
Philippine Health Secretary Francisco Duque III told local media Monday that the government would assess responsibility for the vaccine, which was approved under the previous administration, and consider charges against its manufacturer. The case has quickly turned political, as allies of President Rodrigo Duterte call for an investigation into the vaccine's approval process.
In a reply to a request for comment, Sanofi said it doesn't comment on legal topics, but noted 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." It said the company had "not seen any evidence of increased incidence of severe dengue in vaccinated individuals in the real world experience with the vaccine."
In a statement last week, Sanofi Pasteur, the firm's vaccinations division, said the new analysis of clinical data highlights the complex nature of dengue infection. "We are working with health authorities to ensure that prescribers, vaccinators and patients are fully informed of the new findings, with the goal of enhancing the impact of Dengvaxia in dengue-endemic countries," said Su-Peing Ng, global medical head of Sanofi Pasteur.
Sanofi said the vaccine had been launched in eleven countries: Brazil, Mexico, Costa Rica, Indonesia, Guatemala, Salvador, Peru, Singapore, Paraguay, Thailand and Philippines.
Brazil's health-care regulator Anvisa said on Nov. 29 only people exposed to the virus should take the vaccine. It ordered an updating on the drug instructions to users while further studies are done, according to a statement.
It remains unclear how many people have taken the vaccine in Brazil. In the state of Parana, however, about 300,000 people have taken at least two out of three doses comprising the full vaccination cycle since late 2016, according to a spokeswoman for the local health department who added there have been no reports of serious side effects.
Dengvaxia was recommended for use by the World Health Organization in April last year. It was the first of its kind, targeting a mosquito-borne disease that afflicts some of the world's poorest countries.
Dengue infects about 390 million people a year globally, 96 million of whom require treatment, according to the WHO. Of those, about half a million are admitted to hospital, and 2.5% of all cases are lethal. The virus causes a severe flulike illness marked by painful joints and extreme fatigue.
Paulo Trevisani and Noémie Bisserbe contributed to this article.
Write to Jake Maxwell Watts at email@example.com
(END) Dow Jones Newswires
December 04, 2017 14:28 ET (19:28 GMT)