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Coronaviruses roadmap:
Vaccines

Research roadmap for coronavirus vaccine development

Download 202402 Draft Coronavirus Vaccine research roadmap Final

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Inactivated vaccines

Dependencies

Next steps

Inactivated vaccines

Research Question

  • To examine whether killed virus represents a realistic route to
    immunity and regulatory approval, especially in the post mRNA, viral
    vector landscape. The case may be stronger for animal vaccines than
    human vaccines, since multivalent inactivated vaccines are popular
    already in this space

Research Gaps and Challenges

  • Inactivated vaccines are still widely used and have established efficacy,
    e.g. for influenza, Rotavec, and SARS-CoV-2. It remains to be seen if
    their use and practicality can be replaced by a next generation of
    vaccines, and whether this is a globally applicable scenario or restricted
    to certain countries
  • Improved adjuvants would help tackle the relatively poorer cell-mediated immune response
  • There are multivalent formulations, e.g. Rotavec – could this be
    expanded to other hosts?

Solution Routes

  • Side-by-side comparison of efficacy between different vaccine
    platforms
  • Cost benefit analysis of production pipelines to understand the barriers to implementation of newer technologies
  • More research on adjuvants and/or how to boost cellular immunity

State Of the Art

  • Inactivated virus vaccines designed to combat canine coronavirus seem
    to be a good example of long-lasting protective immunity, generally
    eliciting protective immunity 21 days after the primary vaccination and
    lasting one year. However, it has proved difficult to induce prolonged
    strong immunity with some other animal coronavirus vaccines.
    From past experience in SARS-CoV, dengue virus, measles and
    respiratory syncytial virus vaccines, inactivated vaccines are associated
    with concerns of antibody-dependent enhancement (ADE).
    (Xu L., Ma Z., Li Y., Pang Z., Xiao S. Antibody dependent enhancement: Unavoidable problems in vaccine development. Adv Immunol. 2021;151:99–133)
  • China used an inactivated SARS2 vaccine extensively, Sinovac, to manage the pandemic. There are extensive studies comparing vaccine efficacy between this vaccine and other vaccines, e.g. PMID: 35412612
  • While safer in terms of reversion, inactivated vaccines often require adjuvants to boost immune responses. Examples include trivalent vaccines like Rotavec Corona for cattle (administered to pregnant cows to provide passive immunity to calves through colostrum) and Nobivac Canine1-Cv for dogs (vaccine is particularly useful in multi-dog environments, such as shelters and breeding facilities, where outbreaks of CCoV can spread rapidly). However, these vaccines may not induce the same level of cellular immunity as live attenuated vaccines