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This article originally appeared on Time.com. 

Last summer, public health experts were on high alert due to the rapid spread of the Zika virus, which has now been proven to cause birth defects and other health problems in infants. Today, experts know far more about the virus than they did at the start of the outbreak. Here’s what you need to know now about Zika.

Should pregnant women worry about Zika while traveling?

Short answer: yes. “Our general advice is that if you are pregnant, you should not go to places where Zika virus transmission is ongoing,” says Dr. Lyle Petersen, director of the division of vector-borne diseases at the U.S. Centers for Disease Control and Prevention (CDC). “It’s all a matter of risk. Obviously, if you are staying in an air-conditioned hotel, your risk may be less. However, are you willing to take that risk? We know the consequences of infection of the fetus are huge and lifelong.”

Petersen recommends people check the CDC website for guidance on what locations have active Zika transmission. The CDC updates this list regularly, sometimes on a daily basis. If an area is no longer on the list, Petersen says it’s considered safe to travel. Currently, the CDC recommends that if a pregnant woman or her partner travel to an area with Zika, the couple should use condoms every time they have sex or avoid sex for the rest of the pregnancy, even if they do not have symptoms of Zika.

Should women who plan to get pregnant avoid traveling to places with Zika?

Women who are planning to get pregnant, and their partners, should also pay attention to where they are traveling. The first trimester, during which women may not know they are pregnant, appears to be the most risky time when it comes to Zika-related health complications for infants down the line.

The CDC recommends that women who travel to areas with Zika who want to get pregnant in the near future wait at least eight weeks after their last possible exposure to the virus before trying to conceive. For male partners, the CDC advises waiting six months after the last possible exposure before trying to conceive. Using condoms is also recommended for the waiting period.

What if I am invited to a destination wedding in a place with Zika? Should I not go?

It may be challenging to get a firm yes or no from your doctor about whether or not you should travel for a major event, though the recommendations are not to go to places with active Zika transmission if you’re pregnant or want to be soon. “My job is to give guidance; I never tell people what to do,” says Dr. Richard Beigi, the chief medical officer of the Magee-Womens Hospital of University of Pittsburgh Medical Center. “But I think the travel warnings are there for a reason, and nothing has changed from last year other than the fact that we have more information that has validated that Zika causes congenital health problems. The overall risk is the same.”

Deciding to travel despite the risk is ultimately a personal decision. “I ask my patients, ‘Do you really need to go?’ For some people, the answer to that is yes, and that’s fine, and I give them the best advice I can,” Beigi says.

Should I worry about traveling to places that have the types of mosquitoes that can spread Zika?

The CDC recently reported that the types of mosquito that carry Zika, Aedes aegypti and Aedes albopictus, are appearing in more counties in the southern U.S. where they haven’t been before. But unless the mosquitoes are transmitting Zika, there’s a “very, very, very low risk,” Petersen says. “In all of the places where we have this kind of mosquito that can spread Zika virus, we also see the kinds of mosquitoes that can spread West Nile and other diseases,” says Petersen. “General mosquito precautions in the summer are important for everybody—not only pregnant women.”

How likely is it that I will get Zika?

Experts can’t give a definitive answer to a person’s chances of getting Zika if they travel to a place that has reported spread of the disease. But experts are getting closer to understanding the likelihood of adverse events should a pregnant woman get infected.

A recent study found that one in 10 pregnant women in the U.S. with a Zika infection had a baby with brain damage or other serious birth defects. The first trimester was the most critical time: 15% of women with confirmed Zika infection in the first trimester had babies with birth defects. Another study found similar numbers for women in U.S. territories, revealing that during their first trimester, nearly 1 in 12 had a baby or fetus with Zika-associated birth defects.

“Out of the data collected, it appears that 5-10% of the time a woman gets Zika during her pregnancy, there will be in impact,” says Beigi. “Most of the impact is a malfunction; some of it is miscarriage. Probably the absolute risk of you having a problem is not very big, but it’s not zero, and it’s hard to know.”

How bad will Zika get in the U.S. this summer?

It’s unclear how many cases of Zika will be expected in and outside the U.S. this summer, though experts say it could be lower than last year. “Based on historical evidence, we would expect that outbreaks this year throughout the Western Hemisphere are going to be less than they were the year before,” says Petersen. “It’s not going away, but since a lot of people have already been infected and are no longer susceptible to infection, it will lower the number of cases over time.”

So far in 2017, about 650 Americans have gotten Zika, though that it is considered an underestimate. Most people do not experience symptoms and will not know they have the virus.