Zika is still circulating, but it’s no longer the global emergency it was in 2015–2016. Transmission persists at low levels across parts of the Americas, Asia, and Africa, with occasional sporadic outbreaks. In 2024, roughly 44,500 Zika cases were reported in the Americas alone, with Brazil accounting for 97% of them. The virus hasn’t disappeared, and the risks it poses, particularly to pregnant women, remain serious.
Where Zika Is Circulating Now
Global case counts dropped sharply after 2017, and Zika no longer dominates headlines the way dengue does. But the mosquitoes that carry it haven’t gone anywhere. The CDC maintains a list of 89 countries and territories with current or past Zika transmission, spanning Latin America, the Caribbean, Southeast Asia, sub-Saharan Africa, and the Pacific Islands. Popular travel destinations on the list include Mexico, Brazil, Thailand, the Philippines, Indonesia, and the Maldives.
Surveillance for Zika is limited in many countries, which means cases often go undetected or unreported. The CDC notes that it may not have accurate data on the current level of risk in many of these regions, and detection of new outbreaks can be delayed. In 2019, locally transmitted cases were reported in Europe for the first time. So while the massive outbreaks of 2015–2016 haven’t repeated, the virus continues to simmer in tropical and subtropical regions worldwide.
Why Most People Never Know They Have It
About 80% of people infected with Zika never develop symptoms. Those who do typically experience mild illness: low-grade fever, rash, joint pain, and red eyes lasting a few days to a week. For the average healthy adult, Zika is far less dangerous than dengue or malaria. This is part of why it faded from public attention, but it’s also what makes it deceptive. People can carry and spread the virus without realizing they’re infected.
The Pregnancy Risk Hasn’t Changed
The reason Zika triggered a public health emergency was never the virus itself but what it does to developing babies. That risk is unchanged. Among women with confirmed or possible Zika infection during pregnancy in the U.S., about 5% of babies were born with Zika-associated birth defects. When infection occurred in the first trimester, that number rose to 8%, or roughly 1 in 12.
The most recognized of these defects is microcephaly, where a baby’s head and brain are significantly smaller than expected. But Zika-associated birth defects go beyond head size. The umbrella term “congenital Zika syndrome” includes brain abnormalities, eye damage, joint problems, and restricted movement. Some of these effects aren’t apparent at birth and emerge as the child develops.
Notably, even asymptomatic infections during pregnancy carry risk. About 1 in 25 women who had no symptoms but tested positive for Zika still had a baby with birth defects. This makes screening and prevention especially important for pregnant travelers, since you can’t rely on feeling sick as a warning sign.
Zika Can Also Affect the Nervous System
Beyond pregnancy, Zika is linked to Guillain-Barré syndrome, a condition where the immune system attacks the nerves, causing muscle weakness and sometimes temporary paralysis. A multi-country analysis estimated roughly 2 cases of Guillain-Barré per 10,000 Zika infections. That’s a small percentage, but during a large outbreak it can translate into hundreds of cases overwhelming hospitals. Most people with Guillain-Barré recover, though it can take weeks to months and some experience lasting weakness.
Sexual Transmission and Conception
Zika is unusual among mosquito-borne viruses because it can also spread through sex. The virus can persist in semen longer than in blood, which is why the CDC recommends that men wait at least 3 months before trying to conceive after possible exposure, whether or not they had symptoms. For couples not planning pregnancy, condoms or abstinence for the same 3-month window reduces the risk of sexual transmission.
This matters for anyone whose partner has recently traveled to an area with Zika activity, even if neither person felt ill.
Testing Has a Narrow Window
If you suspect you’ve been exposed, timing matters for testing. The standard approach uses a molecular test (called NAT) on both blood and urine samples collected at the same visit. This test is most reliable when done within 14 days of symptom onset. After two weeks, the virus is generally no longer detectable in blood or urine for non-pregnant individuals, making diagnosis harder. Pregnant women are an exception: Zika RNA can persist in their blood for up to 12 weeks, so the testing window is longer.
No Vaccine Exists Yet
Despite years of development, there is still no approved Zika vaccine. Over a dozen candidates have entered clinical trials using various approaches: DNA-based vaccines, mRNA vaccines (including two from Moderna), inactivated virus vaccines, and vaccines built on other viral platforms like measles or adenovirus. The most advanced candidate, a DNA vaccine called VRC5283 developed by the U.S. National Institutes of Health, reached phase II trials. But progress has stalled broadly across the field, partly because declining case numbers made it difficult to run large efficacy trials. Without a major outbreak, it’s hard to prove a vaccine works.
This creates a catch-22: the virus is quiet enough that vaccine trials struggle to recruit, but not gone enough that the need has disappeared. If a large outbreak re-emerges, the lack of a ready vaccine would be a significant gap.
What This Means for Travelers
If you’re traveling to tropical regions, Zika should still be on your radar, especially if you’re pregnant or planning to become pregnant. The practical steps haven’t changed: use insect repellent containing DEET or picaridin, wear long sleeves and pants when feasible, stay in places with air conditioning or window screens, and be aware that the mosquitoes that carry Zika (Aedes species) bite primarily during the day, not just at night.
Zika is no longer a global emergency, but calling it “over” would be inaccurate. It’s a low-level, ongoing threat with serious consequences for a specific and vulnerable group. For most travelers, the risk is manageable with basic precautions. For anyone pregnant or planning pregnancy, it requires more careful planning around where and when you travel.