The heartbreaking photo that smashes the most favoured claim of anti-vaxxers.

When baby Aryn was born, her parents weren’t able to take her home to enjoy cuddles, bath time and adorable baby gurgles.

Instead, they were stuck in a US hospital while they watched their newborn daughter fight for her life.

Why? Because shortly after her birth, Aryn was diagnosed with HIB flu, which, despite the name linking it to influenza, is a bacterial infection that causes illness in babies and young children.

Infections can range from mild, like an earache, to severe bloodstream infections.

It's an infection that, at one time, was all but eradicated, thanks to vaccines. It's so rare that Aryn's doctor had never seen another case in her entire career.

Aryn's aunt, Alecia Rankin, shared a heartbreaking image of the baby girl in hospital on Facebook page, urging others to consider the consequences of not vaccinating their children.

"My 7 week old niece has HIB flu. So rare that her doctor hasn't seen it in her career because this bacteria caused by HIB flu was all but eradicated by vaccines," Alecia wrote.

"The first being the one babies get at 2 months, which she hasn't gotten yet."

Speaking to Scary Mommy, Alecia said it appeared her niece initially had a stomach bug, but when her symptoms progressed, a spinal tap revealed she had the HIB infection.

She was given an IV in her head and arm, and ended up have a PICC line (a central catheter) when those stopped working.

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After watching her niece fight in a hospital just weeks after her birth, Alecia has a message for those that don't believe in vaccinating their children.

"Before you decide not to vaccinate your children because 'it's your choice' and 'those who are vaccinated won't be affected' remember that babies can get sick before they have the chance to get their vaccine," she wrote.

Doctors and health officials promote the use of vaccines to help achieve "community" or "herd" immunity. When a large proportion of a community is immunised against a contagious disease, there is little chance of an outbreak.

Herd immunity is especially important to protect the most vulnerable members of society: babies who are too young to receive their immunisations, like Aryn, as well as those who are unable to receive vaccines due to allergies or other reasons.

Thankfully, little Aryn is now home and recovering well, but Alecia says seeing her niece so sick has inspired her to fight back against the dangerous rhetoric spread by anti-vaxxers.

"I fully believe in vaccinating our children and the fact that I had to see my niece in pain and extremely sick from an illness that can be prevented by vaccinations, further solidifies that belief," she told Scary Mommmy.

It's a message that echoes that of Camille Echols, a Georgia mum who shared a heartbreaking image of her 11-year-old daughter crying in a hospital emergency room in June.

"I've seen smart-ass memes saying, 'Why would my unvaccinated kids be a threat to your vaccinated kids if you're so sure they work?'" Echols posted on Facebook.

"THIS is why. There are people who cannot have live vaccines, like my daughter.

"She was exposed to a child with chickenpox this weekend and now we are in the ER. She's getting lab work, injections of immunoglobulin and then we have to wait to see what the infectious disease doctor says."

LISTEN to the latest episode of Mamamia's parenting podcast, This Glorious Mess: