Zika Virus Facts and Statistics: What You Need to Know

The most recent Zika virus outbreak in the United States (U.S.) occurred in 2016, and 5,168 people were diagnosed with Zika that year. Since 2018, Zika cases have been on the decline, and as of July 2022, there are no current outbreaks of Zika worldwide. This article will highlight important facts and statistics about the Zika virus.

Pregnant woman looking at departure monitor

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Zika Virus Overview 

Zika is a rare, mosquito-borne illness caused by the Flaviviridae virus. If a Zika-infected mosquito bites the human skin, the virus can travel into that person's bloodstream. Zika can also pass to a fetus through the placenta during pregnancy. Less commonly, it can also be transmitted through sex and blood.

Most people with Zika don’t show any symptoms. When symptoms occur, they are usually mild and include:

Zika can lead to complications, including:

How Common Is Zika Virus? 

The first Zika virus outbreak in the U.S. was in 2016, and cases spiked that year. However, cases have been on the decline since 2018. 

In 2022, getting the Zika virus in the U.S. is very rare because there is no current outbreak. The following are Zika statistics from the United States and its territories over the past several years:

  • Of the 224 locally acquired cases in 2016, 218 were contracted in Florida, and six were contracted in Texas.
  • There have never been reported cases in Alaska or Hawaii.
  • The last reported locally acquired cases in the continental U.S. were in 2017.
  • The last confirmed case in the U.S. territories occurred in 2019.
  • There have been 32 documented travel-associated cases since 2019.

The following table provides facts from available statistics from 2015–2020 in the U.S. and U.S. territories.

Zika Statistics
Year Locally (U.S.) Acquired Cases U.S. Travel Associated Cases U.S. Territories Locally Acquired U.S. Territories Travel Associated
2015 0 62 9 1
2016 224 4,944 36,367 145
2017 7 445 665 1
2018  0 74 147 1
2019 0 28 73 1
2020 0 4 57 0

The locally acquired cases of Zika reported in the U.S. Territories in 2020 were discovered by antibody testing. The test cannot differentiate an active virus from an old infection, so the number does not represent the number of active Zika virus cases that year.

Zika Virus by Age and Gender 

Previous reports show that the Zika infection rate is higher among people ages 20–49 and among people assigned female at birth. The following are statistics regarding the 5,168 confirmed Zika cases in the U.S. in 2016:

  • About 80% were 20–59 years old.
  • The average age was 37.
  • People assigned female at birth accounted for 3,307 (64%) of the cases.
  • The majority of cases (95%) were related to travel.
  • Forty-five cases were sexually transmitted; of those, 43 (96%) were people assigned female at birth.

These reports note that the sex differences in confirmed cases could be due to increased testing. The possibility of experiencing pregnancy complications and passing on congenital disorders influenced many non-menopausal adults to test.

Causes of Zika Virus and Risk Factors 

Flaviviridae, a virus that an Aedes aegypti mosquito can carry, causes Zika. The Aedes mosquito thrives in wet areas such as the Gulf Coast of the U.S., especially in the warmer months. The risk is highest when the Aedes mosquito is most active; two hours after sunrise and a few hours before sunset. 

Zika can spread through: 

  • Mosquito bites (most common)
  • Pregnancy (from mother or parent to fetus)
  • Barrier-free sex (penis-to-vagina transmission is more likely)
  • Sharing blood (e.g., through needles)

Pregnancy and Zika Virus

Though pregnancy does not increase the risk of getting Zika, getting Zika while pregnant increases the risk of pregnancy complications and congenital disorders. 

Risk factors for getting the Zika virus include:

  • Traveling or living in a warm, wet climate
  • Having unprotected (condomless) sex with an infected partner
  • Blood transfusions

What Are the Mortality Rates for Zika Virus?

The survival rate is the percentage of people who survive a disease for a specified time, but it may be presented in several different ways. 

The overall survival rate for non-congenital (adult) Zika is over 99%. Severe illness or death due to Zika is extremely rare. The following data is from the 5,168 U.S. Zika cases in 2016: 

  • There were 153 (3%) people hospitalized.
  • There were 15 (0.3%) people diagnosed with Guillain-Barré syndrome.
  • There was one reported death. 

What Do We Know About the One Reported Death?

A case study shows that the one reported death occurred in a 73-year-old man. He had a decreased immune system from radiation therapy, which he completed for prostate cancer a month before getting travel-related Zika. 

The Zika virus can cause pregnancy complications and congenital disorders related to the eye or brain. U.S. Zika 2016 outbreak statistics related to pregnancy or babies include:

  • About 5% of babies with birthing parents who had Zika during pregnancy were born with Zika-associated conditions present at birth.
  • The highest number of congenital disorders occurred six months after the outbreak's peak.
  • Areas with widespread local transmission had four times the number of congenital disorders.
  • Zika-associated congenital disorders occurred with two out of 25 (8%) infections in the first trimester, 6% in the second trimester, and 3.8% in the third trimester.

Screening and Early Detection

Because the number of Zika cases is currently low, very few people require Zika testing. When needed, diagnosis occurs through the following blood tests:

  • Molecular: A molecular test detects a current Zika infection.
  • Serological: The serological test looks for antibodies. It is not recommended for pregnant people because it can detect antibodies from past infections or similar viruses.

Testing is recommended if you:

  • Have symptoms of Zika, even if you feel better
  • Traveled to a country with a current Zika outbreak
  • Are pregnant and have Zika-associated fetal anomalies on an ultrasound
  • Have delivered a baby with a congenital disorder that could be related to Zika
  • Are pregnant and were recently exposed

Prevention Techniques

There is currently no vaccine or medication available to prevent the Zika virus. However, when you are in high-risk areas or seasons, you can follow these Zika prevention techniques:

  • Avoid areas with an outbreak while pregnant.
  • Have sex with barrier devices such as condoms or avoid sex, especially while pregnant.
  • Remove standing water around your home.
  • Stay indoors when possible.
  • Use an Environmental Protection Agency-registered insect repellent when outdoors.
  • Wear long-sleeve shirts or pants when outdoors.

Anyone who travels to high-risk areas should take steps to prevent mosquito bites for three weeks upon returning home. They should also practice safer sex for several months because Zika can stay in semen for months after infection.

Learn More About Current Outbreaks

You can learn about current outbreaks through the updated Centers for Disease Control and Prevention (CDC) list. Before traveling, search by disease or country and follow these color-coded alerts:

  • Green or level 1: Low concern, take usual precautions
  • Orange or level 2: Practice additional precautions, especially for at-risk populations
  • Red or level 3: Avoid non-essential travel to that area

As of July 2022, there are no current outbreaks of Zika worldwide. However, the most current significant outbreak was in India in November of 2021. 

The following are regions that have had outbreaks in the past: 

  • Africa
  • France
  • India
  • Pacific Islands
  • South and Central America
  • Southeast Asia
  • The Caribbean
  • U.S. Gulf Coast


Zika is a rare virus most commonly spread to humans through bites from the Aedes mosquito. You can also spread it through sex and infected blood or to a fetus during pregnancy. Zika can cause pregnancy complications and congenital disorders. 

There are no medicines or vaccines to help prevent Zika, so other prevention techniques are important, especially for pregnant people. Those who travel can bring the virus back with them and should use prevention techniques after they return home.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Brandi Jones, MSN-ED RN-BC
Brandi is a nurse and the owner of Brandi Jones LLC. She specializes in health and wellness writing including blogs, articles, and education.