Twelve months on from losing her newborn daughter to a common virus, US woman Abigail Friend is continuing her campaign to raise awareness over the dangers of cold sores.

Just two days into her short life in May 2018, baby Aliza got sick from coming into contact with an adult with the HSV-1 virus.

The HSV-1 virus is the common cold sore virus which is fatal to infants until at least two weeks old.

"By the time they [doctors] caught it, it had already spread to her brain," Friend told Newshub.

She says it feels like her heart has been ripped out of her chest and her pain isn't going away after losing Aliza more than one year ago.

Friend has been in therapy for the past few months, to help with her depression and anxiety. She was only 18 when Aliza died.

According to the NZ Herpes Foundation around 80 percent of Kiwi adults have oral herpes. They warn that the virus can be deadly for newborn babies and can also cause a range of other serious health issues.

Friend has been using a Facebook page, Aliza's Story, to warn other parents of the virus that can be fatal.

She says that there is no way of knowing who infected her daughter, and believes it could have been anyone from family, to her close friends to hospital staff.