Zika Virus Vaccine Hunt Begins Following 4,000 Brazilian Birth Defects
This article was originally published in Scrip
The pharma industry's (and the media's) interest in Ebola has begun to wane as more affected African countries secure disease-free status from the World Health Organization, but another tropical condition has started to capture headlines – Zika virus (ZIKV), a mosquito transferred disease reportedly responsible for approximately 4,000 child birth defects since Oct. 2015.
This time the focus is on Brazil, the location for the 2016 Olympic Games, where an outbreak of ZIKV is thought to be responsible for more than 3,893 cases of suspected microcephaly in newborns since Oct. last year. This number represents a huge increase in the condition that causes children to be born with abnormally small heads and brain defects, which affected only approximately 150 babies in the whole of 2014 in Brazil.
ZIKV is generally mild and only causes symptoms in one in five people and the link between ZIKV and microcephaly has not been clinically established. However, 49 babies with suspected microcephaly have died and Brazil's health ministry says in five of these cases an infection with ZIKV was found. No other explanation for the surge in microcephaly has been suggested and the US Centers for Disease Control (CDC) has issued interim guidelines for pregnant women during this ZIKV outbreak, which include suggesting all pregnant women consider postponing travel to areas where ZIKV transmission is ongoing.
There is currently no vaccine for the prevention of ZIKV infection or a medicine approved to treat the disease but Brazil's health minister Marcelo Castro has recently visited the Instituto Butantan, a biomedical research center affiliated with Sao Paulo state health authorities, to discuss the possibility of developing a vaccine against ZIKV. Furthermore, two other national research facilities, the Evandro Chagas institute in Par� and BioManguinhos in Rio de Janeiro, are said to be looking for partnerships with scientific institutes for the future production of a vaccine against the disease.
"A vaccine is the best solution," said Castro in statements on the Brazilian government's website. "We are in contact with international labs and with our Brazilian labs to develop in record time a Zika vaccine. It will be much simpler to develop than the dengue vaccine, which has four serotypes, whereas Zika has only one." ZIKV is transmitted to people primarily through the bite of an infected Aedes species mosquito – the same insect that spreads dengue and chikungunya viruses.
The health ministry will distribute 500,000 PCR (molecular biology) diagnostic tests for ZIKV, which will allow public labs to do 20,000 tests a month, up from 1,000 a month previously. Increasing the number of tests will help with studying the virus, the Brazilian government has said. The more samples analyzed every week will mean more information to work with.
Vaccines In Development
Scrip could find no record of any clinical trials ongoing for this tropical disease. However, on Jan. 22 GeneOne Life Science and Inovio Pharmaceuticals announced a collaboration to advance a DNA-based vaccine for the preventing and treating ZIKV.
Inovio said it would leverage its experience in vaccine development for related viruses, including the West Nile, dengue, and chikungunya viruses, to develop a ZIKV vaccine candidate. The jointly developed vaccine is currently undergoing preclinical animal studies to evaluate its immunogenicity. Inovio and GeneOne Life Science are already partners for two Phase I stage vaccines: INO-4212, a vaccine for Ebola infection, and GLS-5300, a vaccine for MERS infection.
Young K. Park, CEO of GeneOne Life Science, said in a statement, "We aim to be on the front line of defense against major emerging infectious disease such as Ebola, MERS and now the Zika virus."
How Is ZIKV Spread?
Mosquitoes become infected with ZIKV when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites. These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases and are known as "aggressive biters."
The most common symptoms of ZIKV disease are fever, rash, joint pain and conjunctivitis (red eyes).
The CDC says a mother already infected with ZIKV near the time of delivery can pass on the virus to her newborn around the time of birth; it says this is "rare", however. It is also possible ZIKV could be passed from mother to fetus during pregnancy, the CDC says on its website, but this is still being investigated. The Instituto Fiocruz in Paran�, another public research institute, has found evidence of intrauterine transmission between mother and fetus after studying placenta samples from a pregnant woman who had presented symptoms of the virus and miscarried.
There has been one report of possible spread of the virus through blood transfusion and one report of possible spread of the virus through sexual contact.
Cases Outside Latin America
As of Jan. 21, the CDC had confirmed around a dozen cases of ZIKV in Florida, Hawaii, Illinois, New Jersey and Texas. It has been reported that Hawaii health officials said a baby recently born with microcephaly at an Oahu hospital to a mother who lived in Brazil in the spring was infected with the virus in utero.
All cases reported so far are in patients who have recently traveled to regions where ZIKV is active and as of yet there is no indication that US mosquitoes are spreading the virus.
The CDC has issued a level-2 travel alert for regions where ZIKV transmission is ongoing, this covers: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Suriname and Venezuela.