Luck? Genetics? Italian island spared from COVID outbreak
GIGLIO ISLAND, Italy — Stranded on a tiny Italian island, a cancer researcher grew increasingly alarmed to hear that one, and then three more visitors had fallen ill with COVID-19.
Paola Muti braced for a rapid spread of the coronavirus to the 800 closely-knit islanders, many of whom she knows well.
But days passed and none of Giglio’s islanders developed any COVID-19 symptoms, even though the conditions seemed favorable for the disease to spread like wildfire.
The Gigliesi, as the residents are known, socialize in the steep alleys near the port or on the granite steps that serve as narrow streets in the hilltop Castle neighborhood, with denselypacked homes built against the remnants of a fortress erected centuries ago to protect against pirates.
Dr. Armando Schiaffino, the island’s sole physician for around 40 years, shared Muti’s worry that there would be a local outbreak.
“Every time an ordinary childhood illness, like scarlet fever, measles or chicken pox strikes, within a very few days practically all get” infected on Giglio, he said in an interview in his office near the port.
Muti, a breast cancer researcher at the University of Milan where she is an epidemiology professor, decided to try to find out why it didn’t happen this time.
Were residents perhaps infected but didn’t show symptoms? Was it something genetic? Something else? Or just plain luck?
“Dr. Schiaffino came to me and told me, ‘Hey, look, Paola, this is incredible. In this full pandemic, with all the cases that came to the island, nobody is sick.’ So I said to myself: ‘Right, here we can do a study, no? I am here,’” Muti said.
What was especially puzzling to her was that many of the islanders had had close contact with the visitors.
But no other case has surfaced on Giglio, including since the lockdown was lifted in early June, and tourists from throughout Italy have been arriving.
Intrigued about why “the virus didn’t seem to interact” with the island’s native population, Muti hadn’t reached any conclusions by the time she was preparing to leave the island this month. She plans to write up her study for eventual publication.
It’s possible, Muti guessed, that islanders weren’t exposed to enough COVID-19 to get infected.
That possibility was also voiced by Massimo Andreoni, head of infectious diseases at Rome’s Tor Vergata hospital. He noted some patients are simply less capable of spreading the disease for reasons that are still unclear.
Chance might have played a role, said Daniel Altmann, a professor of immunology at Imperial College London. “It could be something more or less trivial — nobody got infected because through good luck there was little contact,” he said in an email exchange.
Or, Altmann also noted that “it could be something important and exotic,” such as a genetic variant common among the island’s population.
With many of the Gigliesi intermarrying through generations, Muti would like to do a genetic study someday if she could obtain funding.