The British scientists are now suggesting that Zika Outbreak, currently working its way through Latin America, will likely end in the next two to three years, as people will develop immunity after the first infection. The scientists are calling it “herd immunity” – a type of immunity that a high percentage of population develops either naturally after an infection or through vaccination.
Neil Ferguson, the lead scientist on the project, from the School of Public Health at Imperial College London, explained that the infection does not strike the same person twice and this will likely lead to a stage where no more people will be left to be infected — thanks to the immune system that generates antibodies against the virus.
This is commonly known as the ‘herd immunity’ where a disease, usually an infectious one, has run so rampant in the community and infected so many people that there are a very small number of people left without it. Even if a person who has no infection history gets the disease, he or she cannot spread the infection forward. This restricts the possible chances of an epidemic or an outbreak.
The research team from the UK predicts that the Zika infection will show a similar pattern of disease spread and burnout in a few years for at least a decade, with only small intermittent outbreaks in some areas.
Similar patterns of disease transmission have been seen in infections like Chikungunya which is propagated by the same mosquito vector responsible for Zika virus. Aedes Aegypti. The Zika transmission predictions are based on mathematical and statistical analysis of other such similar infectious diseases (like dengue).
This is welcome news for agencies and pharmaceutical companies working on Zika vaccines. No preventive therapies or vaccines have yet been developed for the disease which has been linked to congenital anomalies like microcephaly in children born to infected mothers. The link was first established last year when the first 1,600 cases of microcephaly came to light after a Zika epidemic in Brazil.
However, in a press release last month, Inovio Pharmaceutical announced that they received approval from FDA, to conduct Phase 1 trial of their new Zika vaccine GLS-5700 on human subjects.
Number of people suffering from Zika virus Infection is nearly at 12,000 in Colombia and the mosquito-borne disease has infected a total of 691 and 1,305 people in American states and territories respectively. The disease, declared a public health emergency in Latin America by the World Health Organization (WHO), has also affected many health policy decisions.
In some cases, women have been advised to delay pregnancies for some years to avoid congenital anomalies in infants. Ferguson agrees with this policy implementation but advises that the pregnancy hold off period should be recommended on the basis of geographical area as the outbreaks and infection transmissions can vary due to the seasonal patterns of the vector mosquitoes.
The other key recommended areas of focus for policymakers, according to Ferguson, should be immunological interactions with dengue virus, El Nino-driven climate changes, viral evolution, and regional genetic variations in mosquito vector A Aegypti.
The UK scientists highlight that vector control with the help of insecticides has only sometimes worked on a large scale and its effectiveness needs to be enhanced. According to them, it is probably too late to control the spread of the virus but it can be slowed down which would take longer to build herd immunity. This could lead to shorter time between the epidemics.
The insecticide repellent industry is booming in United States currently. New cases of Zika have resulted in a total of 99 million units of insect repellents being sold in the last year, which accounts for a 648 percent boost in a single year. The biggest insect repellent manufacturer in the world, SC Johnson, has also amped up both its production capability and the price of its products in anticipation of coming mosquito season.