30 June 2016

Zika virus vaccine will be tested on volunteers

Two experimental Zika virus vaccines worked on mice: it took one reception

Ivan Sychev, Geektimes

The World Health Organization has recognized the outbreak of the Zika virus in South and North America as an emergency. In 2015, scientists said that the virus causes microcephaly in infants, and doctors have registered more than 4,000 such cases in Brazil. The virus from Africa got close to the United States – at the moment, five children with this anomaly were born in the country, and in February 2016, the first case of infection was registered in Russia.

Due to the confidence that the Zika virus does not cause irreversible changes and death in humans, vaccines against it have not been developed, which increases the risk of the disease. American scientists have published in Nature the results of an experiment (Larocca et al., Vaccine protection against Zika virus from Brazil): two vaccines against the virus worked on mice, which makes it possible for further work in search of a vaccine for humans.

The virus causes the same type of fetal abnormalities in both humans and mice, penetrating through the placenta. Scientists from Beth Israel Deaconess Medical Center and Harvard Medical School have published the results of testing two types of vaccine on pregnant female mice. The first vaccine contains fragments of virus DNA, the second contains inactive virus particles. In both cases, a single injection of the drug helped protect mice from Zika virus strains obtained from patients from Brazil and Costa Rica. The vaccines triggered the production of antibodies, and the animals then showed complete resistance to the disease.

A few days after taking the vaccine, no virus was found in the mice. Protection lasts at least two months. At the same time, a high level of the virus in the blood was registered in the control group.

The creation of drugs based on DNA and an inactive virus are two common ways to develop vaccines. Two commercial companies have received permission from the FDA to test a DNA-based vaccine in humans.

The Zika virus is carried by Aedes mosquitoes, transmission from man to woman is possible – the virus was detected in the seminal fluid and urine of patients. It causes rash, fatigue, headache and joint pain, fever and swelling of the joints. It was discovered in 1947 in the Zika forest in Uganda, and in 1968 it was found in humans in Nigeria. In total, until 2014, fifteen cases of the disease were registered, according to doctors, not dangerous to humans and passing in a few days. Later during the epidemics, scientists suggested that the virus causes Guillain–Barre syndrome and microcephaly in infants.

Guillain–Barre syndrome is manifested by sensitivity disorders and autonomic disorders. Patients develop symmetrical paralysis of the leg muscles, which gradually spreads to the arms. In severe cases, paralysis reaches the respiratory muscles, which can cause death from respiratory failure. During the epidemic in French Polynesia with a population of 270,000 people, 73 cases of the syndrome were identified, which may be related to the virus.

In Brazil, up to 150 cases of microcephaly in infants were registered in 2014, and in 2015, during the Zika virus epidemic, this number increased to 4,180. Then the Director General of the World Health Organization noted that a causal relationship between the virus and malformations in the development of children has not been established, but "there are strong suspicions about its existence." In November 2015, the Brazilian authorities confirmed that infection during pregnancy causes microcephaly in the child, and the authorities of El Salvador in January 2016 asked the residents of the country not to give birth for two years.


On this occasion, the alarm was sounded in the United States: at the moment, five babies were born with this anomaly. Florida Governor Rick Scott signed a government order allocating $26 million for preparation and rapid response to the Zika virus, but the US Senate did not support the funding.

Portal "Eternal youth" http://vechnayamolodost.ru  30.06.2016

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