A coronavirus study has revealed a person with a twin who has already died of the disease is more likely to die as well.
The latest findings, revealed by a team of scientists in Australia, looked at cCovid-19 cases where at least two pairs of twins died within hours of each other from the virus.
The experts believe a person's genetic make-up may influence how their body responds to the virus, and how resilient they may be to fight it off.
The study looked at the case of 37-year-old Katy and Emma Davies, who died at Southampton General Hopsital in April, Nine News in Australia reports.
The sisters, who lived together and both had underlying health problems, had been ill before contracting the virus.
Similarly, Eleanor and Eileen Andrews, 66, lived together and had underlying health problems before dying of Covid-19.
The study also looked at siblings, with brothers Ghulam Abbasm, 59 and Raza Abbas, 54 from Newport, Wales dying, and Olume Ivowi, 46 and Isi Ivowi, 38 from Luton also succumbing to the virus.
Professor John Hopper, director of Twins Research Australia said there is no evidence to suggest twins are more likely to experience fatal symptoms of coronavirus, nor are they more susceptible to infection, than any other people.
But if one twin becomes infected and suffers a particular symptom, their twin is more likely to experience it the same way.
Which in turn means if someone dies after contracting the virus and their twin is also infected, it is more likely the infection will be fatal.
Prof Hopper told Nine News: "If one is predisposed to certain symptoms, the other one is likely to experience the same thing because of their genetics. But that doesn't mean twins are more susceptible to contracting or dying from coronavirus.
"Studying twins give you information about the role of genetics on how the virus affects someone. What we're seeing is there is an enormous variation in outcomes if you are infected with Covid-19.
"By studying twins, you're controlling genetic factors and environmental factors to determining how two people might cope."
The Twins Research Australia is currently looking at thousands of pairs of twins to see how they react both physically and mental to the virus.
