Table 4.

Some of the key challenges to successful SARS-CoV-2 vaccine development.

Challenges to SARS-CoV-2 Vaccine Development
Induction of only modest protection
Aberrant Ab responses: OAS and ADE
Aberrant T cell responses: VAERD, Th2 skewing, OAS
Vaccine AEs, SAEs, AESI
Determining efficacy in humans
Lack of standardized assays for measuring Abs and CMI
High development costs
Logistics of mass production
World-wide delivery and vaccine program implementation
Affordability for poorer nations
Long-term sustainability if regular doses needed

ADE, antibody dependent enhancement; AE, adverse event; AESI, adverse event of special interest; OAS, original antigenic sin; SAE, serious adverse event; VAERD, vaccine associated enhanced respiratory disease.