How bad is this flu season?
Google's search analysis suggests we are experiencing the worst flu season since the 2009 H1N1 season forcing hospitals to postpone some procedures to deal with the influx of patients, though Ministry of Health tracking says we are only slightly above average.
Google.org, the search giant's humanitarian arm, has tracked flu trends in 29 countries since 2008 by correlating past flu numbers from health ministries with aggregated search terms that produce similar graphs.
California-based engineers crunch the numbers and are able to give "real-time" estimates of flu prevalence, often about two weeks before conventional tracking numbers are known.
Google's tracking in New Zealand this year shows the search-volume data spiking higher than any year other than 2009 when the H1N1 influenza produced a huge spike in search volumes.
The massive influx of patients thanks to the onset of winter has forced some Auckland hospitals to postpone scheduled, elective procedures.
Waitemata DHB Chief Executive Dr Dale Bramley said the upswing in patient presentations at Auckland's North Shore and Waitakere Hospitals was stretching capacity and had created challenges for staff.
Presentation numbers at the hospitals' emergency departments during the past two weeks were about 20 per cent higher than during the same period last year, which meant the hospitals were regularly operating at 100 per cent capacity, Bramley said.
The surge of patients meant some scheduled, elective procedures had been postponed to ensure there were enough beds for acute and urgent cases, he said, adding that it was possible further procedures would need to be postponed if the current trend in patient numbers continued.
Bramley said he was mindful of the impact the postponements had on the affected patients and their families.
Staff had also taken on extra shifts to help manage demand during the past couple of weeks, he said.
Real world tracking by ESR through the National Influenza Surveillance System however, is showing New Zealand broadly in line with last year and only just above the threshold average of 39 cases per 100,000 people.
National Influenza Specialist Group spokesman Dr Lance Jennings, a clinical virologist, said readings for July 7-13 were at 40.4 presentations per 100,000, slightly up from the week before which recorded 40.2.
"It's tracking up but not as high as suggested by Google," he said.
Jennings suggested that Google could actually be tracking respiratory illnesses rather than influenza as many of their symptoms were similar.
"What they're tracking is people who are interested in influenza."
"It's still a mild season," he said.
Results were recorded at 80 general practices throughout New Zealand.
Doctors swabbed the first person who presented with symptoms on Monday, Tuesday and Wednesday mornings and sent the results to a virus lab for testing.
Jennings said H1N1 was the dominant influenza virus in New Zealand this year.
The virus, which tends to be particularly severe in younger adults, had circulated throughout the summer.
Some patients required hospitalisation and intensive care when it appeared in pockets in Geraldine, Hawke's Bay and Otago.
In 2012, H3N2 was the main influenza virus, which is more severe in the elderly.
Jennings said official influenza statistics had a four to 10 day lag so it would be interesting to see if Google's predictions eventuated in the coming week.
The best protection against influenza was still an influenza vaccine shot, he said.