A team of British scientists announced on Monday (15.12.2014) that they had discovered antibodies against all four types of the dengue virus.

Since the four known serotypes DENV 1 to DENV 4 differ by 30 to 35 percent in their amino acid sequences, the creation of a vaccine that dealt with all four was considered unlikely. Patients who have survived infection from one of the four serotypes, for example, are not immune against the other three.

Amino acid sequence

During their research, scientists took 145 antibodies out of human cells and isolated and characterized them against various types of dengue. In doing so they found a previously unknown epitope, or receptor for immune responses, which is able to bind with antibodies and T-cell receptors.

This epitope was effective against all types of dengue. And it destroyed viruses in insect cells and human cells.

The US Center for Disease Control estimates that 400 million people - roughly one in 20 worldwide - contract the dengue virus; the World Health Organization (WHO) puts the number at 50-100 million. The discrepancy is related to how countries report incidences of dengue fever.

The virus is transmitted by yellow fever mosquitoes and Asian tiger mosquitoes, and is primarily spread in tropical regions of Africa, Asia and America. The WHO estimates that 12,500 die annually.

Infections have also occurred in more moderate zones like California or the Mediterranean area.

Second infection

A dengue fever infection causes high fever, nausea, and aching in the head and muscles.

If patients later contract dengue fever a second time, the illness is more severe. The body can go into shock, with internal bleeding and hemorrhagic fever.

A process known as antibody-dependent enhancement (ADE) is what makes the second round so devastating. Through ADE, the new virus piggybacks on now-neutral antibodies generated during the primary infection, thereby optimizing the absorption of the virus into cells and facilitating its multiplication.

This makes it difficult to develop a vaccine, since it has to be ensured that the vaccine can not contribute to ADE.

Alternative vaccine?

The development of a vaccine on the basis of the newly found antibody might still take months or even years.

Meanwhile, an alternative vaccine might be ready for the market in mid 2015.

That vaccine, called ChimeriVax, was developed by French company Sanofi Pasteur and is now being tested in three phases. Its goal is to thwart all four types of the dengue virus.

The company is first testing it on more than 10,000 children and adults in many countries of Southeast Asia and Latin America. One phase involving the CYD-TDV vaccine, however, was considered a failure.