A new report from the U.S. National Institute of Allergy and Infectious Diseases (which is part of the National Institutes of Health), together with scientists from Washington University in St. Louis, and Emory University in Atlanta, indicates that vaccination against a single strain of Zika virus will be sufficient to protect the general population against all genetically diverse strains of the virus.
Zika virus is a member of the Flaviviridae virus family. The virus causes a mild illness known as Zika fever in around one in four people. The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes.) Zika virus strains are grouped into two distinct genetic lineages: African and Asian. The strain responsible for the current outbreak affecting the Americas (including cases being reported as far North as the U.S. state of Florida) is from the Asian lineage.
U.S. National Institute of Allergy and Infectious Diseases scientists have shown that when a person is infected with Zika virus, the body’s immune system produces antibodies which fight the infection. Once produced, the antibodies confer protection to the person against future infection from other strains of the virus.
RoyalCollegeObsGyn (@RCObsGyn): “IN THE NEWS: Scientists believe they are close to developing a vaccine to protect people from the Zika virus.”
This immunological response provides the basis of vaccine to protect people from the disease. The potential of a universal vaccine has recently been tested in mice, with a high level of success reported. This happens because all strains of Zika virus have identical surface antigens (which means they are of the same serotype.) This means a universal vaccine against Zika is easier to develop than another Flaviviridae virus like Dengue fever, which has four serotypes. A serotype is a genetically distinct variation within a species of virus.
Rachel Glickhouse (@Riogringa): “Dengue has much worse symptoms than Zika and kills more people. But the new vaccine in Brazil is very pricey.”
For the research, scientists collected serum samples from individuals infected with Zika virus with in South America. The samples were mixed with multiple strains of the virus. The results of the viral combination were examined to determine how effectively the serum antibodies neutralized the virus. The data showed antibodies produced after an infection with the Asian lineage of the virus could effectively inhibit all Asian lineage and African lineage strains. The study was then replicated using infected mice.
The findings are of significance in race to develop a preventive Zika vaccine. The study has been published in the journal Cell Reports, in a paper titled “Broadly neutralizing activity of Zika virus-immune sera identifies a single viral serotype.”
