The NHS are warning that the UK is going to have a bad flu season this winter because there has been a bad flu season in the southern hemisphere this year.
But maybe they got a bad season this year because we got a bad season last year. Surely if this bad season alternates between northern and southern hemispheres one affecting the other then once a bad season starts all seasons have to be bad after that.
What is more puzzling is how is their bad season going to become our bad season? If it is being spread by air travel then why didn't we have a bad summer flu season? Why does it only kick off in our winter after their winter and flu season is over. The idea was that we get more flu and colds in winter because we spend more time in doors passing it to one another in the winter. I agree in an agrarian society where behaviour changes with seasons but I spend as much time in my office in the summer as I do in the winter. That is apart from the summer vacation but if I went to New Zealand won't I bring back the flu?
A big factor in my job and exposure is schools. The new school term brings colds and flu. Now we have much shorter summer holidays for schools in the UK we should see longer flu seasons if this is part of the cause for flu being seasonal. Seasonal flu is reality but our models as to why it is seasonal don't fit very well. We need to get some better models as to why it is seasonal and how it spreads between hemispheres.
Humidity and temperature have been shown to have effects but I suspect that there are more factors to take into account and imagining how flu seasons spread between hemispheres is another factor to consider.