It has been shown that nonenveloped viruses such as murine norovirus (MNV) are inactivated by a visible USP laser through the ISRS process,16 whereby the USP laser pulses excite Raman-active vibrational modes on the capsid of the nonenveloped virus––MNV. The amplitude of the vibration is linearly proportional to the laser intensity. When the laser intensity is sufficiently large, the excited amplitude of vibration on the capsid can become extremely large, leading to the breaking of weak links such as hydrogen bonds and hydrophobic contacts in the capsid of the virus. This causes the capsid to disintegrate into subunits. The virus becomes inactivated because of the loss of integrity of its capsid. On the other hand, it has been demonstrated that enveloped viruses such as murine cytomegalovirus (MCMV) are inactivated by a visible USP laser via the ISRS process as well but through a different route/pathway.19 The USP laser pulses excite Raman-active modes on the proteins of the capsid as well as the tegument proteins of the enveloped virus––MCMV through the impulsive stimulated Raman scattering process. The excitations, which break the hydrogen bonds and hydrophobic contacts on these proteins, cause partial unfolding of the proteins. These unfolded proteins will rapidly reform their broken weak hydrogen bonds and hydrophobic contacts and return to their original folded configuration. However, if the concentration of proteins is very high, such as in the case of proteins confined within the capsid of a virus, they can form hydrogen bonds and hydrophobic contacts with other proteins nearby, leading to the aggregation of proteins. This has been the case for the enveloped virus––MCMV. Aggregation between capsid proteins and tegument proteins has been found to be the cause of inactivation for an enveloped virus. All influenza viruses are enveloped viruses. Therefore, we believe that the most likely inactivation mechanism for the H1NI influenza virus inactivated by the visible USP laser studied here is the ISRS process. The TEM images of H1N1 influenza virus before and after the USP laser irradiation, shown in Fig. 4, further support our argument. The striking similarity between these TEM images to those of MCMV,19 i.e., the retention of the capsid and the global structure of the virus, suggests that the effects (and, therefore, the underlining inactivation mechanism) of the USP laser irradiation on these two enveloped viruses are the same.