Zika Returns to Hawaiʻi in 2025

After six years without reporting a Zika virus case, the Hawaiʻi Department of Health (DOH) is investigating travel-related cases involving two individuals.

On May 27, 2025, the DOH announced that vector control teams are responding and will continue operations in areas where individuals have spent time, including the Waialua/Haleʻiwa area on the island of Oʻahu.

While Hawaiʻi has mosquito species capable of transmitting Zika, but the virus is not established in the state. As of June 2025, no locally acquired cases have been documented in Hawaiʻi.

The most recent travel-related Zika case in Hawaiʻi was reported in 2019. Travel-associated cases were more frequently reported in Hawai‘i during 2015-2019 when Zika was circulating globally, peaking at 25 cases in 2017.

Over the last few years, there has been a significant increase in Zika cases reported in the Americas, including in Puerto Rico. During 2025, over 12,600 cases have already been reported.

The DOH says Zika can also be transmitted through sex from a person who has Zika. The virus has been found in semen, vaginal fluids, saliva, urine and breast milk.

While most people recover from this mosquito-transmitted disease, pregnant women and their unborn children may become infected, leading to serious health issues. 

A study published in January 2025 found that the mortality rates among 11.4 million children born with a severe Zika virus infection were higher. Young children with congenital Zika syndrome (CZS) had a 13-fold higher risk of death compared with those without CZS.

This study found a cause-specific mortality hazard ratio of 30.28.

As of June 2, 2025, the U.S. Food and Drug Administration has not approved a vaccine that prevents Zika.

The U.S. CDC says, regardless of where you live or visit, if mosquitoes are active in your area, wear long clothing and use insect repellent to reduce the risk of bites. Additionally, travelers returning from an area with a risk of Zika should take steps to prevent mosquito bites for three weeks after their return.