Cases of a respiratory virus have exploded in Rotorua, leaving some affected children in intensive care or transferring to Starship Hospital.
There were no cases of respiratory syncytial virus (RSV) in the region last year.
Lakes District Health Board paediatrician Dr Steve Bradley said the first case was diagnosed on June 11.
"Since then cases of this have exploded and currently a large number of children are presenting with this illness."
In the last few days, up to seven patients were admitted each day, Bradley said.
While some children would come on to the ward for fluids - administered either through a tube in their nose or occasionally via an IV line - some also needed extra oxygen.
"A few are seriously unwell and need to be cared for in our Intensive Care Unit, and a few even need to be transferred to the paediatric ICU in Starship Hospital," he said.
Bradley described RSV as a "really nasty and highly contagious" virus that affected but was not isolated to children.
"While it causes a fairly mild cold and maybe a mild chest infection in adults, young children and particularly babies can get really sick with it as it causes narrowing of the breathing tubes, which are already tiny in small babies."
Children could present with what starts as a cold and a runny nose but it would soon spread to the lungs, causing wheezing and difficulty breathing.
"Occasionally, little babies - under about two months after their expected birth date if they were premature - can get this illness and their breathing can become somewhat intermittent so they breathe fast and then pause.
"Pauses with breathing, called apnoeas, can be a first symptom of the RSV illness. If any baby has worrying pauses with their breathing, especially if they are young and might have an early cold or chest infection, then they should be seen by a doctor urgently."
Most young children and babies with RSV infections could be cared for at home but should be seen by a doctor if there were concerns about how they were breathing and feeding, Bradley said.
"Mostly, they don't need to come to hospital and our hospital would be overwhelmed if all babies with this came to our emergency department or into our ward."
RSV disappeared during last year's lockdown and Bradley believed it was eliminated across the country at the time.
"However, it didn't disappear in Australia and it appears that it has re-entered Aotearoa in the last few weeks and is now well-established. Last year's cohort of babies wasn't exposed and so they are now getting ill with it, along with the current group of infants."
Rotorua Home-Based Child Care service manager Zandra Harding said an average of nine out of the 58 children in their care had been absent due to sickness this week, two of them with diagnosed RSV.
"[It is] definitely a lot more than it usually would be. We have this roll-on effect with all these children presenting with sickness, I'm not sure all are RSV, but now we have two educators who are unable to provide care because they are sick now."
Harding said it was generally easier for home-based childcare as there were a maximum of only four children, but even still, on Wednesday there were 11 children absent and most children had been away for the whole week.
Harding said if parents were trying to determine whether or not their children should be kept home; they should be kept home.
"If they are having to think about it, keep them home. Just to make sure they are well, for their own wellbeing as well."
RSV case spikes have been reported in other New Zealand regions including Auckland, Wellington and Hawke's Bay.
The Institute of Environmental Science and Research maintains a surveillance system at Auckland and Counties Manukau DHBs to help prepare health boards for "intense seasons".
Surveillance showed RSV was the virus most commonly detected in the last week.
"Indicators of respiratory illness severity are currently low, though weekly hospitalisation rates are increasing in recent weeks and have now exceeded historical rates for this time of year and have reached the established baseline rate."
Dr Sue Huang, Institute of Environmental Science and Research virologist said like influenza, RSV was imported from overseas.
"Interesting thing is when we opened our bubble with Australia, they have some RSV, so the people coming in probably brought the virus.
"It is around the same time the bubble opened that coincides with the virus appearing in our community."
She said usually children experienced episodes of RSV in their first two years of life but last year there was a cohort of young babies who were never exposed to the virus due to lockdown and high-level safety measures like social distancing and hand-washing.
"So not only are you getting those children who have delayed exposure of RSV but also the group of babies born after them being exposed," Huang said.
In Tauranga, a rise in RSV cases has seen Tauranga Hospital use extra beds from other wards. Among those admitted were children only 10 days old.
Bay of Plenty health board specialist infection prevention and control clinical nurse Robyn Boyne said both the emergency department and the paediatric ward was affected by the rise in cases.
"We have seen a large number of cases either presenting in ED and or admitted since the end of May, but increasing numbers since June 20."
Boyne told the Bay of Plenty Times last week that so far this year, 14 children and two adults had presented with RSV at Tauranga and Whakatāne Hospitals.
"By way of meaningful comparison, this time two years ago we had seen 26 children and 10 adults presenting with RSV."
The DHB was not able to provide updated numbers yesterday.
Toi Te Ora Public Health medical officer of health Dr Jim Miller said RSV was not a notifiable disease so he did not have statistics on the number of RSV cases in the community.
"We are aware from communication with local laboratories that there is RSV in the community at present."
MIller said Covid-19 protocols and restrictions appeared to have a flow-on effect in preventing other respiratory infections, likely including RSV.
"We may be seeing an increase in RSV and other viral infections this year as people are once again interacting in closer proximity which leads to easier transmission."
Lakes PrimeCare Accident and Urgent Medical Care Centre were also approached for comment.
Tips for keeping RSV at bay:
The usual symptoms of fever, cough, snotty nose, and headache will settle in 7 to 14 days. • Children should stay away from childcare and school until symptoms are better.
• It spreads easily, so attention to hand washing and avoiding close contact with others is important
• Asthma medications like puffers don't help those diagnosed with RSV (unless diagnosed asthmatic) and nor do antibiotics, as this is a viral infection. There is also no immunisation.