Available vaccine platforms

Pros Cons Approved vaccines in use
Whole inactivated (killed) virusEasily manufactured
Strong immune response
Mature technique
Possible Th2 bias
Requires large quantities of virus
Risk of vaccine-enhanced disease
Requires booster shots
Influenza, rabies, hepatitis A, injectable polio
Live attenuated virusEntire viral repertoire
Very strong cytotoxic response
Mature technique
Risk of reversion/recombination
Risk of infection in immunocompromised patients
Requires cold chain distribution
Measles, rubella, mumps, yellow fever
Protein subunitsSimple to produce
Safe, few side effects
Less immunogenic
Requires adjuvants
Slower manufacture
Influenza A strains, hepatitis B, acellular pertussis
Viral-like proteinSafe and stable
Enveloped VLP more challenging to produceHPV, preclinical SARS-CoV-1
DNARapid development
Potential integration to host genome
Less Immunogenicity
Delivery challenging; requires cold chain distribution
Not currently licensed
mRNARapid development
Noninfectious, non-integrating
Low immunogenicity
Delivery challenging; requires cold chain distribution
SARS-CoV-2: EUA from FDA (Pfizer, Moderna)
Viral vectorsSafe
Durable response
Pre-existing immunity against vectorEbola. SARS-CoV-2: EUA from FDA (Johnson & Johnson)
  • EUA = emergency use authorization; FDA = Food and Drug Administration; HPV = human papilloma virus; mRNA = messenger ribonucleic acid; SARS-CoV = severe acute respiratory syndrome; Th2 = T helper type-2 cells; VLP = viral-like protein