“Examining noninfluenza viruses specifically, the odds of both coronavirus and human metapneumovirus in vaccinated individuals were significantly higher when compared to unvaccinated individuals (OR = 1.36 and 1.51, respectively) (Table 5).”
Such an observation may seem counterintuitive, but it is possible that influenza vaccines alter our immune systems non-specifically to increase susceptibility to other infections; this has been observed with DTP and other vaccines. (Benn et al, Trends in Immunology, May 2013) There are other immune mechanisms that might also explain the observation.