The US Food and Drug Administration has recently approved Dengvaxia, marking it as the first dengue vaccine to secure regulatory approval in the United States. This significant development comes as a pressing necessity, especially considering the alarming dengue statistics in countries like India.
Urgency of Dengue Vaccine in India
India is prominently listed among the countries that have endemic dengue. As per the data reported until November 26, 2018, there were close to 89,974 dengue cases, leading to 144 unfortunate fatalities. These troubling numbers signal a dire need for an effective vaccine in India.
Understanding Dengvaxia
Fundamentally, Dengvaxia is a live, attenuated dengue virus. An attenuated virus retains the characteristic ability to elicit an immune response within the body, but its tendency to cause disease is diminished or compromised. Dengvaxia is primarily recommended for individuals between the age of 9 and 16, who have a laboratory-confirmed prior dengue infection and reside in dengue-endemic regions.
Dengvaxia: The Philippines Controversy
Dengvaxia was embroiled in a controversy when it was associated with ten deaths in the Philippines in 2017 post a school vaccination campaign. The causal factor was identified as the Plasma leakage syndrome – a condition where blood vessels initiate plasma leakage. This unfortunate incident abruptly put the Philippines’ immunization drive to a standstill.
Constraints of Dengvaxia
The inception of Dengvaxia revolves around a cocktail of four live attenuated dengue-yellow fever chimeric viruses. A tetravalent vaccine – one with four antigens – ideally should prompt the immune system to identify all four viruses and create antibodies against each one. However, due to interference, a phenomenon where one virus replicates more compared to others, the immune system reacts primarily to that virus. Hence, the vaccinated individual acquires increased immunity towards that specific type of dengue. This results in a tetravalent vaccine physically serving as a functionally monovalent one- leading to partial immunity.
The constraint is that the partial immunity can guard against all four types of dengue but only for a limited duration. Additionally, this vaccine is only suitable for certain age groups.
Key Facts about Dengue and Dengvaxia
| Fact | Description |
|---|---|
| Number of Dengue cases reported in India (up to Nov 26, 2018) | 89,974 |
| Dengvaxia | First Dengue Vaccine to get regulatory approval in the US |
| Age Group for Dengvaxia | 9 to 16 years |
| Number of deaths post-Dengvaxia vaccination in Philippines (2017) | 10 |
The Way Forward
To tackle the dengue threat, focusing on dengue larvae control measures is essential. Effective methodologies include Chemical Control, Bioinsecticides – using Bacillus thuringiensis Israelensis (Bti), a naturally occurring bacteria found in soil lethal to mosquito larvae in water. Biological control of Dengue Mosquitoes through predatory crustaceans should also be an integral part of strategies implemented.
Last Modified: February 6, 2024