They are known as "bunker babies" - children born during the pandemic who have spent their short lives in and out of lockdown.
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And while New Zealanders are now entering a new phase of learning to live with the virus, some pre-schoolers are still living semi-reclusive lives, as the only age group who cannot be vaccinated against Covid-19.
Mum Susan* has not left home much since her baby was born eight months ago, just before the August lockdown.
She said the first lockdown was not too bad, except for the fact his grandparents and aunts and uncles could not visit.
"But the second lockdown and there on has been quite lonely. I can tell he needs more social interaction than I can give him.
"He's now at an age where I could take him out for longer spells, but there's always that question - is it worth it?"
Susan sees family and goes to a coffee morning where she knows everyone is vaccinated - but is reluctant to take her baby to public places or events.
When they do venture out, it can be a fraught experience for both of them.
"I find it difficult to interact with him, so if he gets a bit grumpy or unsettled when we're out, I can't use my facial expressions to distract him."
Neuroscience educator and parenting expert Nathan Wallis said early childhood teachers and others caring for babies should be wearing clear face shields instead of masks.
"Because babies so much need facial expression, make sure if you do need to wear a mask, it's a transparent one so baby can still see your face.
"That will help the child to stay calm because so many cues when we're infants are picked up by non-verbal cues and facial expression."
However, the pandemic has had some positives for pre-schoolers, he said.
While their parents may be climbing the walls, very young children have relished the extra one-on-one time with their families.
"So there will be a lot of infants who will have benefited from being in these times and having their parents at home - that's provided of course that their parents are at least reasonably good at regulating their own anxiety."
Plunket's acting chief nurse Karen Magrath said having a new baby brought a lot of joy but it could be lonely and stressful at times, even when there was not a global pandemic raging.
"We have heard that people are feeling worried about going out so we're really encouraging them to stay connected. Being physically distant doesn't mean you have to be socially distant, so plan playdates outside, that kind of thing.
"The main thing to remember is that if their parents are doing OK, they'll be OK."
Magrath said tiny babies picked up on parental anxiety.
"Even very young ones who don't have the verbal language can understand everything you say. So just being a bit cautious about how much we're talking about the pandemic and children worrying about that is something we can do."
Susan said parents like her were constantly having to assess risk based on partial information.
"I think it would be really useful to have clearer data on what is actually happening for the under-fives in terms of infections, hospitalisation rates and severity of illness.
"If they're being hospitalised, why are they having to be hospitalised? What should we look out for if our kids get sick?
"Because it's really hard to find that reliable information that would help us feel more confident about taking him out into the world."
There was little prospect of "freedom" returning for families like hers and other vulnerable people, who relied on others to do the right thing, she said.
"Masks and high vaccination rates are my baby's only protection.
"There would be the immuno-compromised group, as well as the under-fives, and even doctors and nurses who don't get to escape this situation.
"I'm really surprised there's a group of New Zealanders who have completely blocked that."
Meanwhile, the biggest threat to young babies right now might not be Covid - but other potentially lethal diseases against which they can be protected.
Plunket and other child health experts warn current low rates of routine vaccinations have left babies vulnerable to measles or whooping cough, which will soon be just a plane ride away.
*Susan spoke to RNZ on the condition that her identity was not revealed.