Winter has fully settled across Aotearoa, and with the colder snap now biting, respiratory illnesses are beginning to feel more present in everyday life. Health services are reporting a gradual rise in winter-related calls, with early-season viruses already circulating in communities. At this stage, rhinovirus (the common cold) and RSV are the most commonly detected infections, while influenza is still relatively quiet compared with what is typically expected later in winter.
Health experts say the drop in temperature matters because it changes how people live and interact. More time is spent indoors, windows stay closed, and ventilation often drops, all of which creates easier conditions for viruses to spread through households, workplaces, and schools. While flu has not yet surged, surveillance data suggests that situation could change quickly as winter deepens and transmission conditions become more favourable.
University of Canterbury modelling expert Professor Michael Plank notes that influenza activity remains unusually low for this point in the season, but warns that this can shift rapidly. He says winter respiratory viruses tend to arrive in waves rather than all at once, and while COVID-19 has settled back to low levels after earlier activity this year, RSV is already showing steady increases. He also points out that New Zealand is still within the official flu season window, meaning a significant uptick could still occur at any stage.
Public health experts are also focusing on how people respond as conditions get colder. Dr Nikki Turner from the Immunisation Advisory Centre says winter naturally increases the spread of respiratory illness because people are spending more time indoors in closer contact with others. She emphasises that vaccination remains one of the most effective tools for reducing severe illness, especially for older adults and people with underlying conditions, and encourages people to get protected before flu activity ramps up further. She also stresses the importance of simple protective habits like staying home when sick, good hand hygiene, and reducing exposure in crowded indoor spaces.
Turner adds that influenza can have broader health impacts beyond the initial infection, particularly for vulnerable groups, and says reducing the severity of illness is just as important as preventing it altogether. She encourages people who are eligible to consider flu and COVID-19 vaccination together where appropriate, noting that both viruses continue to circulate in the background even when they are not dominating case numbers.
As the cold weather tightens its grip, health authorities expect RSV and other common winter viruses to remain active, with influenza likely to build later in the season. For now, the situation is described as early winter circulation rather than peak pressure, but experts say the shift in temperature is a clear signal that the season is moving into its higher-risk phase.
