Table 2.

Comparison of vaccine platforms.

Characteristic	Attenuated virus	Inactivated virus	Vectored viral	VLP/protein	DNA	RNA
Platform experiencea	Classical	Classical	In development	Classical	In development	In development
Vaccine-associated risk of infectionb	Present	Present	Present	Low	Low	Low
Reliance on viral growthc	Present	Present	Present	Absent	Absent	Absent
Epidemic response timed	Slow	Slow	Rapid	Moderate	Rapid	TBD
Stability of vaccine	High	High	High	High	High	TBD
Adverse eventse	Moderate	Moderate	Moderate	Low	Low	TBD

^aExperience with the respective platform is based on the clinical experience of FDA approved vaccines in each group. Protein vaccines such as those for pneumococcal pneumonia and the human papilloma virus (HPV) VLP vaccine would be considered as “classical”, whereas newer approaches such as nanoparticle vaccines in development for respiratory syncytial virus (RSV) are non-classical. Vectored viral vaccines as well as nucleic acid technologies have less clinical experience and/or are in clinical development.

^bVaccine-associated risk of infection refers to the ability of the vaccine components to cause disease. In the case of inactivated or attenuated virus, the risk pertains to the known risk for back-mutations to a virulent state, incomplete inactivation, or contamination of an attenuated viral stock with virulent virus.

^cThe reliance on viral growth is based on whether the replication efficiency of the vaccine strain or chimeric vaccine candidate is a factor in the speed of vaccine production.

^dEpidemic response time refers to the total time to bring a new vaccine into clinical trials and includes vaccine design as well as production. It is, however, noted that there has been significant improvement in protein expression systems in recent years.

^eAdverse events relate to known vaccine-associated reactions including viral-like infections as well as more unique reactions such as development of a lupus anticoagulant observed with adenoviral vectored vaccines.