The rapid outbreak of Zika virus, a mosquito-borne flavivirus known to cause many congenital disorders, has become a major concern in many countries. Individuals infected by this virus experience skin rashes, fever, acute headache, joint pain, and conjunctivitis for up to a week. First identified in humans in 1957, Zika had largely been confined to the African continent until recent times. Over the last three decades or so, it has been spreading to the other parts of the world at an alarming pace. After studying hundreds of cases, the WHO has finally concluded that a Zika virus infection during pregnancy may cause microcephaly, Guillain-Barré syndrome, and a range of neurological disorders.
Researchers at the National Institute of Allergy and Infectious Diseases have developed a Zika vaccine, and the first volunteer from Huston has already received a test dose. In the next phase, over 2,000 volunteers from cities like San Juan, Miami, and Puerto Rico are expected to participate in the study to confirm the effectiveness of this experimental vaccine. The scientists at NIAID are expecting the initial test results to be available by the end of 2017. Anthony Fauci, the Director of NIAID, said that if the next phase of testing gives satisfactory results, and if another Zika outbreak happens in the South American countries, the FDA may permit the release of the vaccine on an emergency basis.
The trial costs $100 million, and the researchers are gradually moving on to the second phase of the two-stage testing. Firstly, the scientists will determine if the vaccine is completely safe and whether or not it can generate an immune response in people affected with the Zika virus. Then, the ideal dosage of the vaccine will be determined. The research team is looking forward to enrolling ninety healthy volunteers (without pregnant women) from San Juan, Miami, and Houston areas. These participants will receive a standard dose of the experimental vaccine and will be monitored for twelve weeks.
Finally, in June, a group of 2,400 individuals including men and non-pregnant women (aging between 15 to 35 years) will be enrolled from diverse geographical locations. This phase determines whether the vaccine can prevent the infection in geographical locations where the test subjects are naturally exposed to the Zika virus. Each participant will be administered either a placebo or an experimental vaccine. He or she will be given three doses, one in every four weeks. Then, all the participants will be monitored for about two years for the slightest signs of Zika infection.
Health experts around the world have already warned about the devastating birth defects caused by Zika infection during pregnancy. Besides microcephaly (a condition characterized by an underdeveloped brain and a small head), these defects include a range of hearing and vision impairments. Most of these conditions cannot be identified until the baby reaches few months of age. The federal data suggests that in the continental U.S. alone, 1228 Zika-infected pregnancies were reported till date, and out of them, 54 babies had birth defects while 7 cases resulted in miscarriages, abortions or stillbirths. With mosquito season only a few months away, officials from the Centers for Disease Control and Prevention (CDC) are warning people to take adequate measures.