Probably. But let’s look at the evidence.
Evidence for existence of freshers’ flu
Surprisingly freshers’ flu has been quite well studied, and there are several large studies. About 10% of the student intake (4919 students) at the University of Minnesota were studied in some detail in 2005 (Nicol, 2005). A staggering 91% of this group reported a cold, or flu like illness.
In another large study (this time at the University of Cambridge, UK) it was suggested that certain courses with more contact time (e.g. medicine and science) were associated with more viral illnesses at the start of academic year, than those with less contact time (Eames, 2023).
By contrast, in another study, arts and humanities undergraduates (also in the University of Cambridge) were significantly more likely to be infected with COVID-19 than science undergraduates (Warne, 2021).
All three studies stated that significant reporting bias was possible as they were asking students about viral illnesses. There were no control groups (same age, month, not at university etc) in either.
Alternative view
There is another view. It may be nothing to do with being a fresher – i.e. it may not exist (or at least may not be anything to do with going to university).
Why? Nearly all university academic years in the Northern Hemisphere commence around the end of September or beginning of October, which is the same time as the start of the annual flu season.
In other words, all the studies are over-interpreting an association to do with the season; and (falsely) concluding there is a causative link between going to university and viral respiratory illnesses.
Or
Or it could be a bit true – i.e. the increased susceptibility to illness from late nights, heavy alcohol consumption and stress peaks 2-4 weeks after arrival at university; and happens to coincide with the seasonal surge in the outbreaks of colds and flu in the Northern Hemisphere.
Other resources
What is freshers’ flu?
What’s the difference between a cold, flu and COVID?
Difference between bacteria and viruses
10 most common student health problems
Flu (NHS website)
COVID advice and services (NHS website)