What You Should Know About the Zika Virus: A Q&A with Tonya Villafana, Infectious Diseases and Vaccines


Tonya Villafana

Monday, 22 February 2016

Why is this virus getting so much attention in the media?

The news media often increase coverage on disease outbreaks, especially ones that haven’t been discussed in the mainstream before. The catalyst for this particular wave of news about the Zika virus has been reports in Brazil of newborns being born with microcephaly, a birth defect where a baby's head is smaller than expected, and the possible link with their mothers being infected with the virus during pregnancy. This potential link is troubling, but has not been formally established. Additionally, the fact that we are also now seeing cases of Zika here in the United States means that the virus has the potential to become even more widespread. In addition, the Olympics are to be held in Brazil later this year. This has created concern that large numbers of people from around the world will be traveling to Brazil with the potential to carry the virus to other locations.

The Zika virus is complicated, and there’s a lot that even clinicians, researchers and public health experts don’t know about the virus, its link to microcephaly, Guillan-Barre Syndrome (GBS) or other potential modes of transmission and long-term consequences.

How worried are you about Zika’s public health impact?

It is concerning, but much is still unknown about Zika. Although severe disease and fatalities from infection are uncommon, there is a growing potential for a pandemic. We’ve already seen outbreaks in Africa, Southeast Asia, the Pacific Islands and South America. Since the reports of outbreak in Brazil, we’ve seen infections in at least 20 countries—including the United States. In part, what’s worrisome is the vector—the Aedes aegypti mosquito, the same species that transmits dengue, chikungunya and yellow fever (and the Aedes albonicus mosquito in Asia). These mosquito populations exist worldwide, which increases the likelihood for global transmission.

Can the virus be fatal?

Fatalities are rare; mostly, the infection is asymptomatic or it causes mild illness like fever, rash, muscle and joint pain, and conjunctivitis. According to the Centers for Disease Control and Prevention (CDC), about 1 in 5 people infected with the virus will get these mild symptoms.

Are there demographic and/or geographic risk factors?

Aedes mosquitoes that carry the virus are the primary routes for transmission. That means that if you live in or travel to an area where these mosquitoes populate, you’re at risk for infection if you are bitten.

The media coverage has focused attention on two possible links to Zika: infected pregnant women who may pass the virus to their unborn children, which results in impact on brain development and microcephaly; and, a potential connection to GBS. There have also been reports of sexual transmission of Zika.

Does Zika have the potential to evolve into a more potentially harmful virus?

It’s more likely that if we see Zika being introduced into new geographic areas, then there is the potential for a new vector species to become involved. If this happens, then clearly the opportunity for more pervasive disease transmission exists.

If there’s no vaccine currently on the market, what can we do to avoid contagion?

Mosquito-borne diseases can be difficult to address. In the absence of a vaccine, the best thing is to minimize the risk of exposure. Repellants, clothing that covers exposed skin, and limiting outdoor activity when mosquitoes are at their most active can help.

Vector control is also going to be important, and this means doing things like reducing the habitats where mosquitoes breed. That includes both physical and biological controls, and may mean the widespread use of traditional methods like insecticides or exploring other options like genetically engineered mosquitoes.

What is MedImmune’s response to the Zika virus outbreak?

We are actively considering how to bring our thought leadership and/or resources to contribute to the response. Some of our collaborators are directly involved in the response, and others that we work with are looking at various possibilities for vaccine development. This would be similar to the way resources were made available for the Ebola response. Other companies that have developed vaccines for dengue or yellow fever are better placed to develop and scale a vaccine more rapidly. We do not think that developing a monoclonal antibody targeting Zika is a viable option for diseases treatment or prevention at this time.

How are countries most affected and other global health authorities responding to the outbreak? I’ve been in close contact with James Hospedales, MD, who leads the Caribbean Public Health Agency (CARPHA) and is at the forefront of the response. James and his team are coordinating the regional response to Zika, which remains a rapidly evolving situation. The World Health Organization announcement of the PHEIC—or public health emergencies of international concern—highlights the health and economic security threat to the Caribbean, Latin America and potentially other regions. In addition to their usual surveillance, lab, and information support to countries, they are actively partnering with the Pan American Health Organization, CDC, and Caribbean travel and hotel tourism sectors. CARPHA presented a position paper to the Caribbean Community and Common Market heads meeting on February 16-17 in Belize. We are all working quickly to respond to Zika in the best way possible.