2 infants are now believed to have died from coronavirus in the U.S.

Two infants are now believed to have died of the novel coronavirus in the United States, after Connecticut’s governor announced the death of a six-week-old newborn baby Wednesday.

Gov. Ned Lamont took to Twitter to announce the news, saying the infant from the Hartford area was brought unresponsive to a hospital late last week and could not be revived.

The Connecticut Department of Public Health said post-mortem testing Tuesday night confirmed the baby was positive for COVID-19.

“This is absolutely heartbreaking,” Lamont said. “We believe this is one of the youngest lives lost anywhere due to complications relating to COVID-19.”

Hartford Mayor Luke Bronin also confirmed the news of the infant’s death while reporting three other fatalities Wednesday due to the coronavirus, along with 70 new cases in that city alone.

“Our heart breaks for that family,” he told reporters. “This disease can be tragically unpredictable and fatal to people of any age.”

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The first infant believed to have died as a result of COVID-19 in the U.S. was announced on Saturday by the Illinois Department of Public Health.

The Chicago infant, who was less than a year old, was announced as one of 13 deaths related to the coronavirus across the state that day.

Health officials and Illinois Gov. J.B. Pritzker said the exact cause of death is still unknown and an investigation is underway, but confirmed the infant tested positive for COVID-19.

China is the only other country that may have seen the death of an infant who tested positive for the disease, though that case is even less definitive. A letter published in the New England Journal of Medicine in March said the 10-month-old died four weeks after being hospitalized with a bowel blockage and organ failure.

Children have made up only a small fraction of coronavirus cases worldwide, and research has found that most of those cases see only mild to moderate symptoms.

A study published in the journal Pediatrics last month that looked at more than 2,000 cases in China under the age of 18 found only 125 children, or six per cent, developed very serious illness related to COVID-19. One of those cases, a 14-year-old boy, died.

Yet more than 60 per cent of those 125 children were aged five and under, while 40 were infants under 12 months old.

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In Canada, only one infant in Ontario is believed to have contracted the disease. That case was reported on March 12, and health officials said the baby was self-isolating at home.

That same day, Alberta health officials announced a two-year-old child had also tested positive.

The latest epidemiological data from Health Canada — which studied just over 5,500 of the 9,712 cases in the country as of April 1 — said only four per cent of cases were under the age of 19.

Of those, just six of them were admitted to hospital, with one of them requiring intensive care.

No deaths due to COVID-19 have been reported among anyone under the age of 30. The youngest person to have died was a 34-year-old Alberta man.