Zika Vaccine: How Long Do We Have to Wait?

By Ronni Sandroff | Feb. 2016  |  Investopedia.com

It’s not a gold rush, exactly. Common wisdom has been that there’s little profit in vaccines, although there are some who dispute that. Nonetheless, companies worldwide have been quick to respond to the towering and urgent need for a vaccine against the Zika virus, which has infected at least 1.5 million people since its outbreak in Brazil this year and is considered the culprit in at least 2,782 Brazilian babies born in 2015 with small heads and underdeveloped brains. There is also likely vision impairment, possibly even in Zika-infected babies who do not have microcephaly.

Gearing Up Around the Globe

Dr. Anthony Fauci, head of NIH’s National Institute of Allergy and Infectious Diseases, has called for “a full-court press” to find a vaccine. In January his agency told scientists it would fund research into basic microbiology, immune response, tests, treatments, surveillance studies and vaccines for Zika.

The epidemic has provoked a vigorous worldwide response from vaccine manufacturers. The Bharat Biotech in India (Private Company Ticker Symbol: BHABIOP), Butantan Institute in Brazil, GeneOne Life Science (KRX:011000) and Inovio Pharmaceuticals in the U.S., Sanofi Pasteur in France and Takeda Pharmaceutical Co. (NASDAQOTH: TKPYY) in Japan are among those who have announced work on a Zika vaccine. Some companies are collaborating with universities, such as Australia’s Sementis Ltd. (with the University of South Australia) and GeoVax (OTCQB: GOVX) in the U.S. (with the University of Georgia). The vaccine pipeline has grown during the last 20 years, with more small and medium-sized companies, including spin-offs of academic research centers, starting Phase I vaccine trials. Industries that support the efforts of research scientists, such as genetic and testing centers, are also gearing up. (See also Cerus Corp. May Have Treatment for Zika Virus and Zika Virus Infects the Travel Industry.)

Zika May Be an ‘Easier’ Vaccine Target

Zika is a flavivirus, a family that includes yellow fever, West Nile, dengue and Japanese encephalitis virus. Fortunately, scientists have a successful track record of making vaccines against flavivirus and can now replicate and study human infections in animal models. Recent advances in vaccine technology, work with similar diseases such as West Nile and dengue and, perhaps most important, expedited testing and approval processes, should speed the effort for a safe and effective vaccine, infectious disease expert William Schaffner, M.D.. told Investopedia. Schaffner, professor of preventive medicine and medicine at Vanderbilt University in Nashville, explains that unlike the flu virus, which has a “devilish capacity to mutate,” flaviviruses are more stable. “If we can create a vaccine it should work in different parts of the world and not need modification over time, making the vaccine a profitable as well as humanity-saving venture,” said Schaffner.

While testable vaccine candidates may emerge in the next six months, Schaffner cautions that safety, as well as effectiveness testing, is essential. Virtually all the contenders project a timeline of three to five years before a vaccine is fully tested and available for widespread use. However, the National Institutes of Health is now hopeful that human testing can begin as early as summer of this year.

Schaffner feels the competitive rush for a vaccine is a good thing since a more organized approach such as that taken with the Genome Project would take more time and might discourage individual initiative. “There’s a lot of exciting scientific ferment and determination that will keep the lights on in the lab at night,” he says.

Disease Outlook for the U.S.

A bite from an infected Aedes mosquito is the main mode of Zika transmission, but there have also been documented cases of transmission from sexual contact and blood transfusions. In the U.S., robust mosquito abatement programs are in place and already being deployed in states reporting cases. In the U.K., planes on routes from Zika-affected countries will be sprayed.

It’s unlikely that Zika virus (or Ebola, dengue fever or chikungunya) will become widely established in the U.S., according to infectious disease experts. People in the U.S. are less exposed to mosquitoes since they are more likely to live in closed, air-conditioned environments and have access to insect repellents.

Preventive measures, such as quarantine or avoidance of infected people, may not be possible with Zika since four out of five victims never have any noticeable symptoms. When symptoms occur, they are similar to those of many other mild illnesses. Fever, rash, joint pain or conjunctivitis (red eyes) are among the most common symptoms, which typically start two to seven days after being bitten. The CDC has a blood test for Zika virus, but it is not yet commercially available.

The eradication of mosquitoes as a species is a measure also under consideration. While a total mosquito apocalypse would rob larger species of an important food source, work is now being done on mass elimination of the disease-bearing Aedes mosquito. This would potentially prevent dengue fever and chikungunya as well as Zika. Oxitec, a British company with a production facility in Campinas, Brazil, is one group that is trying to eliminate Aedes mosquitoes by altering the genes of males in captivity and then releasing them to mate and render the next generation sterile. This method has yet to be widely tested and perfected.

The Bottom Line

Avoiding mosquito bites and travel to infected areas are the top preventive measures against Zika, smart for everyone and perhaps crucial for pregnant women or those who might be, as well as their partners and family members. The usual measures to combat mosquitoes, including not leaving standing water under flower pots and in yards, are important, as is wearing long pants, long-sleeved garments outdoors and using insect repellents. The Aedes mosquitoes bearing Zika are daytime biters and can also bite at night.

Repellents containing DEET, picaridin, lemon eucalyptus or IR3535 are all considered safe to use during pregnancy. Consumer Reports tests found Sawyer Fishermen’s Formula (with picaridin) and Off Deepwoods VIII (with DEET) effective for at least 8 hours against the Aedes mosquitoes. It also found that repellents with plant oils, such as citronella and lemongrass, did not work against mosquitoes. (Also, see Zika Virus: Latest Advice on Staying Safe.)

Some experts in reproductive health now fear that Zika virus belongs to a class of viral infections in utero that since 1988 have been linked to autism, bipolar disorder and schizophrenia, although not yet proved as a direct cause. “Evidence has increased for years that mental illnesses may be linked to exposure during pregnancy to viruses like rubella, herpes, and influenza, and to parasites like Toxoplasma gondii,” Donald McNeil recently reported in the New York Times.

The New York Times also reported that in Brazil, conspiracy theories on the origins of Zika and causes of microencephaly have spread through social media – for instance, blaming chemical larvicide used to kill mosquitoes. With GMO mosquitos released in Brazil a couple of years before the sudden epidemic of Zika, there’s also been a burble of conspiracy theorizing that this could have caused the problem, but the idea has been meticulously rebutted. Transmissions through blood donations and sexual relations have been documented, however, prompting new guidelines.