‘Herd Immunity’: Study Suggests Zika Outbreak Will End When Everyone Is Infected

An Aedes Aegypti mosquito zika Getty

A new study from the Imperial College London suggests the only way to stop the ongoing Zika virus epidemic in Latin America and the southern United States is to wait until everyone has been infected.

The study, the BBC reports, argues that the outbreak is likely to end in around three years, when enough time has passed for every person who lives within range of the aedes aegypti mosquito, which carries the virus, already has the virus in their system. The researchers oppose any attempts to stop the spread of the virus, arguing that slowing down the inevitable will only prolong the epidemic.

“Slowing transmission between people means the population will take longer to reach the level of herd immunity needed for transmission to stop,” Professor Neil Ferguson, who led research for the study, told the BBC. He added that containing the virus may also trigger a second outbreak among those who are not exposed to the virus so that “the window between epidemics could actually get shorter.”

The text of the study, published in the journal Science, argues that Zika is “not containable,” offering as a counterintuitive solution that the virus spread as rapidly as possible to produce “herd immunity” among the affected populations until a new generation is exposed to Zika.

The Zika virus does not cause symptoms in an estimated 80 percent of cases. In the people who do experience symptoms, they are largely mild: muscle aches, rashes, and eye infections. Among adult men, the chances of severe symptoms are so low that an Olympian has committed to competing in the Games after testing positive for the disease. The minor risks typically associated with Zika make the suggestion of mass infection appear a viable option.

Scientists have admitted to largely not understanding how the viral mutation of Zika present in Latin America affects human health, however, particularly among pregnant women and the unborn. Earlier this year, studies proved that the Zika virus causes severe neurological defects in unborn infants. In Brazil, the heart of the Zika outbreak, more than 3,000 infants have been born with microcephaly, a condition in which the infant’s skull is too small for his or her brain and crushes it, causing severe developmental disorders.

“It’s a delayed catastrophe. It is every parent’s worst nightmare,” Dr. Peter Hotez, dean of the school of tropical medicine at Baylor College of Medicine in Houston, tells NBC’s Today, noting that the regions of the United States with the most hospitable climates for mosquitos – including Texas, Florida, and Puerto Rico – are expecting a spike in Zika-related birth defects soon. “I think it is just a matter of time before we see these numbers increase,” Dr. Juan Franco added.

Aedes aegypti is present in all countries of the Western Hemisphere except Chile and Canada.

While the Imperial College London researchers are suggesting spreading the virus further as a means of protection, dozens of medical experts have come out against hosting the 2016 Summer Games in Rio de Janeiro, Brazil, where thousands of cases have been recorded. In addition to being a threat to the Western Hemisphere, tourists from all over the world could unknowingly expose entire populations to Zika, with no trace of the virus in their native land.

“An unnecessary risk is posed when 500,000 foreign tourists from all countries attend the Games, potentially acquire that strain, and return home to places where it can become endemic,” a group of more than 150 medical experts said in a letter to the World Health Organization (WHO) and International Olympic Commission (IOC) in May, demanding the IOC postpone or relocate the Games.


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