- Three promising Zika vaccines
offer hope for protection against the dreaded illness
- Scientists confirmed complete
protection in Rhesus monkeys
- No adverse effects of the vaccine
Deaconess Medical Center (BIDMC) along with scientists from University of São
Paulo and Walter Reed Army Institute of Research (WRAIR) have shown that there
is a definite hope for a vaccine for the dreaded virus.
The Zika virus
causes flu-like symptoms in adults and is transmitted by the Aedes mosquito. It has risen to International concern due to the absence of a vaccine and due to its effects on the unborn child. Fetuses in the mother's womb are affected, leading to the development of microcephaly
(abnormal smallness of the head). Pregnant mothers are, therefore, advised to stay away from Zika prone areas.
‘New Zika vaccines offer hope of protection for humans.’
Origin of the
The Zika virus
gets its name from the Zika forest from where it is believed to have originated
in the year 1947. A number of cases of Zika were identified in Africa, Pacific
Islands and South East Asia. The first ever big outbreak of Zika was reported
in the Islands of Micronesia in 2007.
Another big outbreak in Brazil in 2015 found an association between Zika and Guillain-Barré syndrome
(muscle weakness) and microcephaly, raising concerns about other neurological conditions due to this virus.
The World Health
Organization (WHO) has declared a Public health Emergency for the Virus with
travel warnings issued for people traveling to Zika prone areas.
The rise in the number of cases have prompted scientists to work on probable vaccines
which could offer protection against this disease.
First for U.S
Zika has spread
to the United States, where 14 people have been identified with this disease in
the Broward and Miami-Dade counties. This is the first time the U.S has
witnessed a spread of infection due to mosquito bite, in the recent history.
Another first is
that travel advisory has been issued for people traveling to Miami and Broward,
a first time ever for places withing the U.S.
- A purified inactivated virus (PIV)
which was developed at WRAIR by army researchers.
- A vaccine that is based on
adenovirus vector based and developed by BIDMC.
- Plasmid DNA Vaccine.
Testing the VaccinesPurified
Inactivated Virus (PIV)
injected 8 Rhesus monkeys with PIV and another eight Rhesus monkeys with a
false vaccine. After 4 weeks the monkeys were given a booster dose. The monkeys
were then infected with infectious strain of the virus from Puerto Rico and
Brazil. It was found that Rhesus monkeys that were injected with the vaccine
had enough antibodies against the virus and there was no sign of the virus in
the blood or any other body fluid of the monkeys.
Vector Based Vaccine and DNA Based Vaccine Testing
These vaccines provide a small portion of DNA coding for the outer coat of the virus and they induce the immune system to produce antibodies. 12 Rhesus monkeys were injected with either adenovirus vector based vaccine or DNA vaccine
. It was found that the adenovirus vector based vaccine was more potent than the DNA vaccine. Both the vaccines provided complete protection when the monkeys were injected with infectious strain of the virus from Brazil.
the Vaccines Tested
Zika Vaccine Testing on Humans
- The vaccines that were tested
offered total protection for the Rhesus monkeys against the virus.
- The vaccines were earlier tested
- This is the first instance of Zika
vaccines being effective in primates.
- The vaccines produced no side
testing of various Zika vaccines in primates has prompted Centers for Disease
Control and Prevention (CDC) to approve testing of the vaccine in humans. This
would mark the first comprehensive step towards protection against the deadly
virus. References :
- How Zika spreads - (http://www.cdc.gov/zika/about/overview.html)