“It’s hard to explain to someone who isn’t a twin,” said Aneira. “We call it the twin-ection.”
For Aneira Hayward, 28, who lives in Gateshead, the pandemic and successive lockdowns have meant prolonged separation from her twin sister Anwen in Cardiff.
She said many people with siblings who are not twins “don’t understand” how lonely it can feel.
“It’s different because you’ve shared everything. It’s very strange not having that person around, especially when it’s quite hard mentally.”
A King’s College London questionnaire of more than 3,800 UK twins found only 5.5% were living with their co-twin at the start of the pandemic.
BBC Wales spoke to three sets of twins to hear about how the last year has affected them.
Video by Max Evans