Health officials said Thursday that three people in New York City have been infected with the Zika virus, including a pregnant woman.

The virus, which is transmitted by mosquitoes, has been spreading rapidly in Latin America. All of the people with the virus in the city were infected while traveling abroad, health officials said. None has severe complications. 

Health officials said that since mosquitoes are not active in winter months, there’s “no risk” of getting the virus in the city. However, the city has started to plan a “comprehensive response.”

“We want to ensure all New Yorkers traveling to warmer climates are taking preventive measures, and are prepared as mosquito season approaches,” said Dr. Herminia Palacio, deputy mayor for Health and Human Services.

Most people don’t get sick from the Zika virus, but those who do have symptoms such as fever, rash, joint pain and conjunctivitis. Pregnant women are most at risk; cases of babies born with smaller than normal heads have been reported following the Zika outbreak in Brazil.