Local reports said that the patient was a young pregnant woman who was already in hospital, although her symptoms are said to be mild.
“She was diagnosed with the flu and coronavirus as soon as she arrived,” said Professor Arnon Vizhnitser, director of the gynaecology department of Beilinson Hospital in Petah Tikva.
“Both tests came back positive, even after we checked again,” he told local newspaper Hamodia.
“The disease is the same disease: they’re viral and cause difficulty breathing since both attack the upper respiratory tract,” Prof Vizhnitser added.
The Israeli health ministry said it was studying the case to determine whether the combination of the two infections can cause a more serious illness.
The woman has since been discharged.
While she represents the first documented case of a patient being diagnosed with both the diseases simultaneously, doctors believe there are more cases in the country.
“We are seeing more and more pregnant women with the flu. It is definitely a great challenge dealing with a woman who comes in with a fever at childbirth,” said Prof Vizhnitser.
“This is especially when you do not know if it’s coronavirus or the flu, so you refer to them the same. Most of the illness is respiratory.”
Israel began administering fourth vaccine shots to individuals with compromised immune systems on New Year’s Eve to curb the spread of the Omicron variant.
The country lifted outdoor mask mandates in April, making them obligatory only for large gatherings, and cases have steadily surged since.
Health ministry data showed that 80,523 cases were recorded in Israel on Wednesday. The country has suffered more than 1.67m infections and 8,290 coronavirus-related deaths since the pandemic began.
The head of the army’s coronavirus task force has meanwhile warned that Israel’s healthcare system would “collapse” if Omicron is allowed to spread unchecked, according to Haaretz.