A new mum has banned friends and relatives from kissing her baby - after a peck on the cheek left her newborn struggling to breathe.

Gianna Morrone, 26, was "really nervous" when her tot, Joseph, two months, caught a bad cold after being kissed by a friend with a cold."

The tot needed to take a nebuliser - an electric machine which sprays medicine into the lungs - four times a day for a week, in case the virus spread to his lungs.

Now, Gianna won't even let family members give him a kiss or a cuddle - and says more awareness needs to be raised over the dangers of kissing newborns.

A newborn's immune system isn't usually fully developed until they're three months old, according to John Hopkins Medicine.

Gianna says she'd ban others from being around her little boy - if they didn't "respect that boundary"."

Gianna, a paediatric oncology nurse, from Old Bridge, New Jersey, US, said: "I think people need to realise babies are so vulnerable - they basically have no immune system. "

"I see how fragile Joseph is, and it makes me really nervous. "

"I've stressed to family and friends about the importance of showing affection in other ways. "

"While I don't want to offend anyone, I have to be his voice."

"And people can't just come up to him, and kiss him."

The ordeal started for Gianna two weeks ago, while she was out to lunch with friends.

As they left, one of them gave Gianna a kiss on the cheek, before reaching down to kiss Joseph, too.

The next day, the same friend told Gianna they felt as if they were "coming down with something"."

"I didn't think anything of it at the time," she said. "

"But, two days later Joseph woke up all stuffy. "

"He couldn't really breathe."

Gianna and her husband, Joseph Senior, 27, a mortgage broker, took little Joseph to see their family GP.

The tot was prescribed with a saline nasal solution to clear his airways - and given a nebuliser to prevent the cold from spreading to his chest.

He said to keep an eye on the situation - but if his breathing got worse, they'd need to go to the emergency room.

"It definitely could've been very serious," Gianna said. "

"Babies at this age have no immune systems, at all. "

"Our doctor told us that babies can only really breathe through their nose - which made it difficult for Joseph. "

"Had the cold spread to his chest, he wouldn't have had any antibodies to fight it off."

"So, for about four days, it really was touch-and-go."

Within the week, Joseph began to feel better - but Gianna now has strict rules for anyone wanting to show affection to the newborn.

She often redirects people into smiling at him, touching his toes or rocking him to sleep, instead.

"It's been a bit of a struggle for me, to hold those boundaries," she said. "

"I just say politely to friends and family members: 'Hey, Joseph got sick from a kiss, you shouldn't do that until he gets a bit older and stronger.'"

"It gives me peace of mind to know I set a boundary and spoke my piece."

Gianna says her mum, Gina Persico, 57, a pre-kindergarten teacher, has been much more adamant on family members leaving Joseph alone.

Gianna said: "I had to tell my grandmother - who's very old-school - not to kiss him on the forehead. "

"She tried doing it, the first day we brought him home. "

"My mum had to tell her to stop."

"She said: 'This isn't OK, we shouldn't be kissing him at all - especially now.'"

"If it really came down to it, and after constantly telling someone to not kiss my baby, I probably wouldn't allow them around him anymore."

"I've got to protect Joseph - that's my priority."