Has the Pope changed the Catholic Church's teaching on the use of contraception?

Has Pope Francis just shifted Church teaching against the use of contraception? In remarks during an in-flight press conference from Mexico to Rome, the Pope suggested that using contraception was the "lesser of two evils" in stopping the spread of the Zika virus. 

"Avoiding pregnancy isn't an absolute evil," Francis said. With this phrase the Pope appears to have developed church teaching as, crucially, it calls into question Church teaching that the use of contraception is wrong in every circumstance. 

And if condoms can be used to stop the spread of the Zika virus, can the same be said for preventing HIV and Aids? It should not be forgotten, however, that other popes and cardinals have hinted at shifts to Church teaching in this area. 

According to Francis, Paul VI said nuns in the Congo could use contraception to avoid pregnancy due to rape. And in an interview Benedict XVI suggested a male prostitute with HIV could use a condom. The Vatican then clarified his remarks to say he in no way meant that contraception could be used to prevent pregnancy. 

Cardinals, including Cormac Murphy-O’Connor and Godfried Danneels, argued that condoms could be used if one partner in a married couple had Aids. 

Church teaching states that every sexual act must always be open to life. Hardliners say this prohibits the use of contraception in any circumstance: if a husband or wife has aids then the only option is abstinence. 

Yet if contraception is permitted in certain circumstances - to prevent the spread of aids or other diseases - then this lets the genie out of the bottle, somewhat. Will there be other circumstances where the case can be made? 

Church prohibition on contraception is, according to research, pretty much universally ignored by Catholics in the western world. 

It may be that the Pope has opened up a door for developing that teaching and bridging the huge gulf that exists between what the Church says about sex and what happens in practice.