December 23rd, 2015 (VOA) The Philippines has granted approval for the sales of a new dengue vaccine, following Mexico as the first two countries to allow a treatment that could prevent the flu-like illness that threatens half the world’s population, including Costa Rica, where an average 3,500 cases are confirmed annually in country of 4.8 million where the mosquito-transmitted virus is common.
The recombinant, live, attenuated tetravalent vaccine (CYD-TDV) is the first to hit the market targeting dengue, which is transmitted by the bite of a mosquito and can cause crippling fevers, along with muscle and joint pain.
Dengvaxia, as it has been named by its maker France-based Sanofi Pasteur, comes at a time when a “safe and effective vaccine is urgently needed,” according to the World Health Organization.
While Costa Rican officials have not indicated when – or if – the new vaccine may be made available here, it “has demonstrated clinical efficacy and a good safety profile,” according to medical researchers at Chulalongkorn University in Bangkok in a paper recently published in the Southeast Asia Journal of Tropical Medicine and Public Health.
Sanofi Pasteur said the vaccine has been demonstrated effective against all four dengue virus types.
“The vaccine actually is given in three dose schedules with a six-month interval. It is being given (to people) from nine years of age up to 45 years of age. This is the age range wherein most of the dengue cases are being reported, particularly in endemic countries here in Asia,” according to Dr. Joselito Santa Ana, head of dengue vaccine operations in the region for Sanofi Pasteur.
Hopes for dramatic reductions by 2020
The vaccine’s maker is hailing it as an important tool to reach the World Health Organization’s objective on dengue, a potentially deadly disease for which children are at particular risk.
“Together with vector control it will form an integrated approach in reducing dengue mortality by 50 percent and reducing the dengue morbidity by more than 25 percent by 2020,” Dr. Santa Ana, speaking from Manila, told VOA on Wednesday.
Clinical tests were carried out on 40,000 people from 15 countries.
Some two-thirds of those over the age of nine were deemed to be protected and the vaccine was found to be 93 percent effective against the most severe form of disease, dengue hemorrhagic fever.
While being hailed as a breakthrough, there is concern about vaccinating younger children and an unanswered question about the new vaccine’s long-term efficacy.
A higher incidence of hospitalization in the third year after vaccination among children younger than nine years of age naturally infected with dengue raises a “critical question” whether this is a short-term or long-term phenomenon” noted an editorial in the September 24 edition of the New England Journal of Medicine which suggested booster doses of the vaccine might reduce this risk.
The journal praised the trials as “superbly conducted” while noting, due to traditional concerns about partial, waning immunities the “bumpy road to a vaccine-based solution for dengue continues.”
“As with all new vaccines, it is unknown how long the measured protection against dengue will last,” the WHO also cautioned in November, 2014.
Pharmaceutical companies in Japan, Britain and the United States are also developing dengue vaccines.
Vaccine price still unclear
Another question mark is cost.
Newly developed pharmaceutical products are frequently very expensive when they initially go on sale and not affordable for many patients.
But Dr. Santa Ana said the maker of the dengue vaccine wants to maximize the access to all populations, while acknowledging the market price of Dengvaxia has not yet been established.
“We are committed to offering a fair and equitable price for the vaccine that is sustainable both for the company and the government whose going to implement it in the public program,” he said.
The CYD-TDV vaccine, in development for 25 years, has been submitted for licensing in 18 other countries in Asia and Latin America where dengue is endemic.
India may exempt Dengvaxia from large-scale clinical trials in order to expedite clinical trials, the Economic Times reported Tuesday, quoting health industry sources.
More than 90,000 dengue cases with 181 deaths were reported in India through the end of November for this year.
Dengue was traditionally a disease primarily confined to the tropics. Now, about half of the world’s population is considered at risk due to urbanization, jet travel and climate change.
Dengue cases have soared 30-fold in the last half century, according to the WHO, with an estimated 400 million people now infected annually.
The first doses of Dengvaxia, which utilizes a yellow fever virus with substitutions of two genes encoding dengue proteins, are already being produced in France where manufacturing of 100 million doses annually are planned, according to Sanofi Pasteur.