Read more of our articles on the Zika virus here.

Pope Francis suggested Thursday that for Catholics threatened with the Zika virus, the use of contraception might be acceptable.

Asked during a press conference whether abortion or birth control could be considered a “lesser evil” in response to the Zika virus, which appears to be linked to birth defects, the Pope replied that he believes abortion is a crime and is never acceptable, but that the use of modern birth control (“artificial contraception” in church parlance) may be permitted in exceptional circumstances.

Abortion “is an evil in and of itself” the Pope claimed. “On the other hand, avoiding pregnancy is not an absolute evil,” he said, referring to prior circumstances in which the church has sanctioned the use of birth control, such as in the 1960s, when nuns were subject to rape as a weapon of war in the Belgian Congo.

The World Health Organization has labeled the spread of Zika virus a public health emergency. Women of reproductive age are especially at risk: Based on available evidence, it appears that pregnant people infected with the virus are at heightened risk of giving birth to babies with microcephaly and Guillain-Barré syndrome (GBS). Microcephaly is an incurable neurological disorder that impairs growth of the brain and skull in utero. Symptoms range from mild to severe intellectual and physical disabilities, and there is no cure. In general, microcephaly reduces life expectancy. GBS is an immune disorder leading to nerve damage and sometimes paralysis. It is also associated with the Zika virus.

The Zika virus has now been found in at least 34 countries to date, most of them in Central and Latin America, where abortion is illegal but complications of clandestine abortion remain among the leading killers of women ages 15 to 49. The World Health Organization, which has declared Zika to be a global health emergency, recommends that a first-line strategy to combat Zika include dramatically increasing access in affected countries to antenatal, birth, and postnatal care; neurological and mental health services; and contraception and safe abortion.