Being dengue-wise!:

Long wait for Dengvaxia

by Rukshana Rizwie

While Sri Lanka is one of the hardest hit countries due to by the rising number of dengue cases, Sri Lankans could may have a long wait before they get easy and affordable access to a new vaccine that has just being introduced to the market.

The world's first dengue vaccine - 'Dengvaxia' - was approved after 20 years of research earlier this month. The vaccine which won clearance in Mexico is considered a breakthrough in preventing the mosquito-borne infection that puts half of the world's population at risk.

Dengvaxia which was developed at a cost of US$ 1.65 billion was endorsed by the Mexican regulatory authority for patients between 9 - 45 years, in areas where the disease is endemic. However, the vaccine awaits approval in at least 19 countries before it can be administered to patients. This list also includes Sri Lanka.

"It will be a long time before we can administer the vaccine here," said Dr. Paba Palihawadana, Chief Epidemiologist and Director of the Central Epidemiological Unit at the Ministry of Health. "We will certainly not have it this month. It would most probably be towards the latter part of next year."

Local testing

Dr. Palihawadana explained that the Ministry of Health would be required to do a clinical trial in Sri Lanka before it can be made available locally. She emphasized that details regarding this trial were not finalized and further discussions were on. "Ordinarily when there is a new vaccine, part of the Phase III is trials in various countries. According to the manufacturer (Sanofi Pasteur), it has been cleared in Asia and Latin America, but we will need to do a litmus test here locally."

Dengvaxia 'will be priced at a fair, affordable, equitable and sustainable price, some countries may distribute it free," Guillaume Leroy, Vice-President of the Dengue vaccine team at Sanofi was quoted as saying.

"The vaccine has to be registered globally while the World Health Organization will need to pre-qualify it for use," Dr. Palihawadana explained, adding that the paper work will cause a snag in releasing the vaccine on a global scale.

Meanwhile, Aparna Thomas, a Senior Director of Communications for India and South Asia in an exclusive email interview to the Sunday Observer disclosed that the "Company intends to pursue licensure in more countries in Asia, including Sri Lanka, and will continue to communicate in a transparent manner regarding our regulatory approval plan for the vaccine."

She added that "Asia is an impacted region representing approximately 70% of the global burden of dengue, hence Sanofi Pasteur is committed to delivering this vaccine, upon approval, to Asian endemic countries as well...."

She said the company would work closely with relevant health regulatory authorities to secure the approval and access to the vaccine. "The regulatory file for Dengvaxia(r) has been submitted in 12 endemic countries - in Latin America and Asia. By the end of the year, we will have filed for registration in about 20 countries."

WHO discussions

The WHO Strategic Advisory Group of Experts (SAGE) on Immunization is currently reviewing the evidence for CYD-TDV (Dengvaxia) and will advise the WHO on a policy position for the vaccine.

Their considerations include; vaccine safety, efficacy, disease burden, programmatic suitability and cost-effectiveness.

It is expected that this team will discuss the vaccine at its April 2016 meeting and only then provide recommendations to the Director-General, WHO on the public health utility and any recommendations for use.

In addition to Dengvaxia, there are five other vaccine candidates under evaluation in clinical trials, including live-attenuated vaccines, subunit, DNA and purified inactivated vaccine profiles. Additional technological approaches, such as virus-vectored and VLP-based vaccines, are under evaluation in preclinical studies.

However, the WHO in its website notes that the growing global epidemic of dengue is of mounting concern for the organization while a safe and effective vaccine is urgently needed. The vaccine will be integrated as part of the Global Dengue Prevention and Control Strategy (2012-2020).

Meanwhile, Sanofi Pasteur in a statement published in the Indian press cited that the vaccine would be offered in India only after the Sanofi Pasteur receives regulatory approval. So far, the vaccine has only been granted approval to sell in Mexico.

The vaccine, which is being manufactured in France, is ready to be shipped to India, the company stated, but it was up to Indian regulators to decide when that would happen.

In this backdrop, a study on the efficacy of the vaccine which was published in the New England Journal of Medicine in March this year mentioned three phase III trials on 35,000 children between 2 and 16 years of age, in Asia Pacific and Latin American countries.

The study found that the risk of hospitalisation with dengue fell in patients aged nine and above, compared to the control group. Based on the advice from the technical group on the trials, the WHO noted in 2014 that the vaccine's efficacy against all dengue serotypes combined was estimated at 60.8%.

Trials also showed the vaccine is more effective in people who have been diagnosed with dengue previously and not so much in unexposed populations.

Meanwhile, in Sri Lanka, during the past 11 months of this year, some 26,662 suspected dengue cases have been reported to the Epidemiology Unit from all over the island.

Dr. A. R. M. Thowfeek, Director of the National Dengue Control Unit (NDCU), said that there had been a 'detectable trend' in the number of cases reported from the Colombo district after the rains.

"We've noticed a spike in cases at several Municipal area including Dehiwala - Mt. Lavinia, Battaramulla, Kotte and Kolonnawa," he said. "We've intensified the anti-dengue measures in those Municipalities."

He added that the NDCU has intensified precautionary measures to check the incidence of dengue in those towns. He added that one of the biggest factors was complacency on the part of the residents.

Dr. Thowfeek added that the Director General of Health Services, Dr. Palitha Mahipala, has called for meetings this week for assistance from the Sri Lanka Army, the Ministry of Education, the regional epidemiology units and health services units to intensify the programs due to the increase in the number of dengue cases.