Five people this season, all adults, and two aged 81 and 98, died of seasonal flu complications in Dallas County, Texas, the county's health services office said on Thursday.
The so-called "Aussie flu" is a particularly virulent strain of influenza A and is said to have triggered the huge rise in cases, along with an aggressive B subtype.
Aussie Flu has also targeted the United Kingdom, where it was revealed that nine people were admitted to intensive care or dependency unit with the potentially killer strain.
Dr Kevin Kelleher, from the Health Protection department, said: 'There have been a few deaths already, under 10 people have died so far this year.
A further 73 people have been hospitalised.
'I don't give specific numbers when it's less than 10 because people could be identified.
"You speak to people who've had the flu and know they've had the flu, been told explicity they've had the flu, they often find it hard to get out of bed, it's not an easy thing to do".
Conor wrote on Instagram: "Well that was a wild New Year's Eve". Half the family hit with the Australian flu virus and some even left in hospital with it, ' he said in the post which has since been deleted.
The flu virus indirectly resulted in the death of 1,000 people in Ireland last season.There are three main types of flu virus - A, B and C - and hundreds of different subtypes.
McGregor says that the family's big New Year's Eve party had been canceled at the last minute and he was left "shaking in bed the past two days".
While the symptoms of "Aussie Flu" are similar to the regular flu, they are usually more intense, and while the regular flu should run through your system within a week, if your symptoms persist for more than seven days, check with your doctor to ensure you haven't contracted the new virus.
The A virus has caused some of the worst outbreaks in history, including the infamous Spanish flu in 1918 and swine flu in 2009.
Australia - whose winter occurs during the Irish summer - had one of its worst outbreaks on record, with two-and-a-half times the normal number of cases.
A post from McGregor late on New Year's Eve showed him sick in bed with his son.