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Do You Still Need to Be Worried About Zika?

A close-up of a mosquito sitting on human skin.
Photo: Joao Paulo Burini/Moment/Getty

WWhen Maureen McCollum, now 37, got married during the height of the Zika virus pandemic in 2016, her honeymoon to the Dominican Republic was on the chopping block.

“I would cancel your trip,” doctors said at the time, when the couple expressed that they wanted a baby. In the end, McCollum and her husband traveled but chose to delay trying to conceive for six months, per the doctors’ recommendations.

McCollum is currently pregnant and expecting a baby girl in January. She says her doctors seem less worried about Zika virus now than they were in 2016.

Still, it’s been hard to shift from the conservative mindset McCollum was in when Zika was a more prevalent fixture in the news. “I think in the back of my mind, the extreme caution we had when we were first trying is still playing a role in any decision I would make when traveling too far from home,” she said.

For couples who are trying to get pregnant these days, the dramatic rise and fall of Zika virus from the public consciousness, coupled with the dearth of information about what the actual risk level is for contracting Zika in 2019, has created a minefield.

Even the most scientifically literate couples would be hard-pressed to make a decision about whether or not to book travel plans solely based on the U.S. Centers for Disease Control’s traveler’s health website.

Source: Centers for Disease Control and Prevention (CDC)

Currently there are no Zika outbreaks underway anywhere in the world, but many areas on the CDC’s Zika map have some background Zika risk, according to Dr. Scott Weisenberg, medical director of the travel medicine program at NYU Langone Health.

“It’s very difficult for somebody looking at that map to determine their risk,” he said, pointing out that Brazil, which had 2,650 confirmed Zika cases this year, is in the same risk category as the United States, which confirmed five Zika cases this year, none of which were locally transmitted.

That is partly because while some countries rigorously monitor or report Zika virus cases, other countries do not. “We do not have accurate information on the current level of risk in specific areas,” said Benjamin Haynes, a CDC spokesperson.

Where did Zika virus go?

The World Health Organization declared the Zika virus a public health emergency in 2016 as it ripped through the Americas and threatened the Olympic Games in Brazil. Now, roughly three years later, the dust has seemingly settled.

In March of this year, the CDC downgraded its travel restrictions and in July, the World Health Organization followed suit. (The American College of Obstetricians and Gynecologists says it is aligned with both the CDC and WHO.) But since neither health organization currently lists any active Zika outbreak on their world maps, news headlines referencing the virus have been scant.

Does that mean women are free and clear to travel wherever they want, without worrying about Zika virus? Not so fast, experts say.

“If you’re 100% risk-averse and don’t want to take any chances, the only sure way of avoiding that exposure is by not traveling.”

Zika virus, which is spread by the Aedes aegypti mosquito, has existed for decades in some parts of the world. But the Brazilian outbreak in 2015 and 2016 provoked a global frenzy, in part because of the devastating effects the virus had on Brazilian babies.

Zika’s symptoms are typically mild, including rash, fever, and joint pain, if symptoms crop up at all. Eighty percent of people who are infected with the virus are asymptomatic, and may never know they contracted the disease. (Even when symptoms are obvious, Zika can easily be mistaken for dengue or the flu, both of which have similar symptoms.)

For pregnant women who contract Zika virus, the stakes are far higher. The effects on babies exposed to Zika virus in-utero can be devastating and lifelong. The 2015–2016 outbreak in the Americas led to hundreds of thousands of people contracting the virus and more than 2,000 babies being born with microcephaly, a severe birth defect that causes babies to have smaller than normal heads and can result in developmental disabilities, seizures, feeding problems, and vision loss.

Dr. Albert Ko, a professor of epidemiology at the Yale School of Public Health, has done work in Northeastern Brazil, which was the epicenter of the 2015–2016 outbreak. Infection rates in Brazil were so high during the peak of the outbreak that the epidemic eventually burned itself out, he explained.

“Immunity drove transmission to extinction,” Ko said.

Still, Ko cautioned that just because Zika has waned in Brazil and there haven’t been any reports of ongoing outbreaks doesn’t mean the virus has been eradicated. Since the majority of people who contract Zika are asymptomatic, many likely never realize they’ve been infected in the first place, he explained. “That makes it often difficult to identify whether there is transmission going on, or an outbreak is happening, unless it’s a really large one,” Ko said.

Making sense of the vague travel guidelines

Even today, with Zika long out of the news cycle, Ko said he gets five or six emails a week from women who want to travel asking for his opinion.

According to the CDC’s most recent recommendations, pregnant women and those planning to become pregnant should check with their doctors before traveling to any area that has had Zika transmissions in the past and should not travel to any zones where there are active Zika outbreaks, in the event that a new outbreak occurs.

With the caveat that countries around the world employ different levels of rigor when it comes to testing for and reporting cases of infectious disease, the Pan American Health Organization keeps an ongoing count on their website of Zika cases by country, which is more granular and updated more frequently than the CDC and WHO maps.

Per the CDC and WHO, the rule of thumb for couples who are trying to conceive is to wait approximately three months to try and get pregnant if the male partner has traveled to a country or territory that has ever reported Zika virus cases and approximately two to three months if only the female partner has traveled to those places. Since Zika can be sexually transmitted, men with pregnant partners should use condoms or abstain from sex if they’ve traveled to a Zika zone during the pregnancy.

“If travel to one of these areas is necessary, pregnant women and those planning to become pregnant should take precautions to prevent mosquito bites,” said Dr. Christopher Zahn, vice president of practice activities at the American College of Obstetricians and Gynecologists.

“Women planning to become pregnant should be counseled by a medical practitioner, and counseling should include discussion of the signs and symptoms and the potential risks of Zika virus infection,” Zahn added. Women who are currently pregnant should continue to update their doctors about any travel plans they or their partners have, to assess their risk.

Consulting with a doctor before traveling is paramount, but much of it comes down to how comfortable the patient is with risk. Ko says he usually tells the women who are asking for his advice about traveling before trying to conceive that, “if there’s not a known outbreak or active transmission that’s been identified recently, the risk is likely very small.”

But, “if you’re 100% risk-averse and don’t want to take any chances, the only sure way of avoiding that exposure is by not traveling,” Ko added.

The slow creep toward a Zika virus vaccine

While there’s currently no vaccine available to immunize the general public against Zika virus, the National Institute of Allergy and Infectious Diseases, which is part of the National Institutes of Health, has several vaccine candidates they’re developing and testing. A vaccine would “solve a lot of stress and anxiety for patients,” Weisenberg said.

Zika vaccine research, however, has not been without controversy. One of the vaccine candidates, which is currently in Phase 1 human clinical trials, involves what’s known as a “human challenge study,” meaning that researchers vaccinate willing volunteers with weakened Zika virus. While human challenge studies have been conducted in the past for dengue, malaria, and other infectious diseases, there was still an outcry among some members of the scientific community when the trial was announced.

Critics worried about the long-term health consequences of infecting study participants with Zika virus, and suggested that participants also risked spreading the virus to their sexual partners.

While attention has lapsed since the heyday of Zika, researchers are still driving toward a vaccine outside of the public eye. “Similar to what happens with Ebola, and many of these other neglected diseases that cause these large epidemics, was that as the vaccine was coming out, the epidemic stopped,” Ko said. “That put a big kink into a potentially important vaccine candidates for Zika.”

The NIH asserts that research has not slowed and the institute is hard at work on preclinical and clinical research. On August 19, the Food and Drug Administration fast tracked the biotechnology company Moderna Inc.’s Zika vaccine, a designation that’s meant to fulfill unmet medical needs by expediting treatments for serious health conditions.

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