The Zika virus was first described in 1947. It is a fairly stable virus, unlike the frequently mutating influenza virus. It is mostly a mosquito-borne virus, but the mosquitoes aren’t the only source of buzz surrounding Zika. Recently, in South America, there has been a significant increase in Zika diagnosis and babies born with microcephaly – a major birth defect due to mother-to-child transmission in the womb. While there is no definite proof that Zika is causing microcephaly, the correlation is apparently strong: During the Zika epidemic in Brazil over the past four months, microcephaly cases there rocketed to 3,500, and 46 babies died. For comparison, there were only 147 cases altogether in 2014.
There is a tremendous lack of accurate information with regards to Zika. Even though it was discovered nearly 70 years ago, it hasn’t been studied much simply because the illness it causes in humans was unremarkable. In fact, most cases (60–80%) of Zika are asymptomatic. When symptoms do appear, they tend to be mild, generally 4-7 days of joint pain, rash, and/or fever. It is only recently that a correlation between infection and microcephaly has been noted, and thus the current buzz about Zika.
Like other pandemics, the Zika is spreading quickly and unexpectedly resulting in panic and feelings of helplessness. Similar panic happened with swine flu (2009), avian flu, SARS, Ebola etc.
WHO declares emergency – What’s Next?
There is no vaccine currently available against Zika, so initially the focus for prevention will be vector control – avoiding mosquito bites. Of course, for years global health authorities have tried to control mosquitoes, as they are vectors for other infectious diseases including malaria, dengue, and chikungunya. But mosquito control is difficult. Aedes aegypti, the mosquito species in question, can breed in just a few drops of standing water.
Over the past few days, I have spent some significant time researching the Zika virus.
I don’t expect developing a vaccine will be challenging. While Zika is an RNA virus, like the flu, it is actually quite a stable virus unlike the more frequently mutating flu virus. This means vaccine development is a relatively simple process. There are many methods for producing a vaccine with high effectiveness. These vaccines are based on attenuated pathogens or their external proteins.
Even producing large amounts likely won’t take too long thanks to recent advances in this field. The delay will be regulatory – for very compelling reasons, a vaccine is given to healthy people and a new vaccine must be thoroughly tested for safety and for efficacy in human clinical trials before it goes to market. Consequently, even with the increased attention, and WHO’s declaration of a public health emergency, it will likely be many years, most likely a decade, until a vaccine is available.
I also expect there will be intensive studies to confirm (or perhaps disprove) the direct link between Zika and microcephaly. Hopefully we’ll soon know the cause.
(Image source CDC http://www.cdc.gov/zika/geo/index.html)