  We compare the predictions of AAfrag for the spectra of secondary photons,
neutrinos, electrons, and positrons produced in proton-proton collisions to
those of the parameterisations of Kamae et al., Kelner et al., and Kafexhiu et
al. We find that the differences in the normalisation of the photon energy
spectra reach 20$-$50% at intermediate values of the transferred energy
fraction $x$, growing up to a factor of two for $x\rightarrow\,$1, while the
differences in the neutrino spectra are even larger. We argue that LHCf results
on the forward production of photons favor the use of the QGSJET-II-04m model
on which AAfrag is based. The differences in the normalisation have important
implications in the context of multi-messenger astronomy, in particular, for
the prediction of neutrino fluxes based on gamma-ray flux measurements, or
regarding the inference of the cosmic ray spectrum, based on gamma-ray data. We
note also that the positron-electron ratio from hadronic interactions increases
with energy towards the cutoff, an effect which is missed using the average
electron-positron spectrum from Kelner et al. Finally, we describe the publicly
available python package aafragpy, which provides the secondary spectra of
photons, neutrinos, electrons, and positrons. This package complements the
AAfrag results for protons with energies above 4 GeV with previous analytical
parameterizations of particle spectra for lower energy protons.
