Coronavirus disease 2019 (COVID-19): Vaccines to prevent SARS-CoV-2 infection
Coronavirus disease 2019 (COVID-19): Vaccines to prevent SARS-CoV-2 infection
Vaccination preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
infection are considered the most promising
approach to manage the pandemic. Developing
SARS-CoV-2
vaccine is going on at an unprecedented speed.
Unhuman primate
studies & epidemiologic human trials inform that SARS-CoV-2 infection may
result in evolution of functional neutralizing AB that’re followed by protection against reinfection. These landmarks support
the consideration that a vaccine that produce neutralizing AB could also prevent any subsequent infection. Neutralizing AB
& Th1-polarized cellular immune response are believed to be essential in limiting the risk
of vaccine-enhanced illness. Primarily,
the main antigenic target for SARS-CoV-2 vaccine is the large surface spike proteins that
bind to the angiotensin-converting enzyme 2 (ACE2)
receptor on host cell & resulting in membrane
fusion.
SARS-CoV-2 vaccine is currently
developed via several variable platforms.
Some with traditional approach, e.g.,
inactivated
virus or live attenuated virus platform, others with new approaches, e.g., recombinant proteins
& vector vaccine, and some
have never been employed in a licensed vaccination before, e.g. RNA & DNA vaccine. A variety of vaccine candidates
have shown immunogenicity without major
safety profiles in the early-phases human
studies. 👉Two mRNA vaccine
candidates have also been reported to have about 95 % vaccine
efficacy in prevention of lab-confirmed
symptomatizing coronavirus infection 2019 (COVID-19).
Many vaccines are now available in many countries.
In the US, added to the traditional process
for licensing a vaccine, the FDA can make vaccines that permit specific safety &
efficacy profiles available faster
through an emergency use authorization (EUA). As
regard vaccines allowed under EUA, physicians
should explain to the potential recipients that the vaccine didn’t licensed yet, the reason(s)
it is not licensed, and what are the expected information the FDA is waiting for before commencing a full-licensed
vaccine; a signed informed consent document is currently NOT warranted.
Deployment of the
limited vaccine supplies that will be initially available should be equitable
and efficient. Several expert organizations have provided guidance for vaccine
allocation approaches that maximize the individual and societal benefits of
vaccination. These generally prioritize workers in essential industries
(including health care) and individuals at risk of severe infection. Following availability &
widespread
uptake of SARS-CoV-2 vaccination, efficacy
profile that were not considered
in clinical studies will need to be assessed, include the following: 👉
1)
Longevity of
protection & possible need for more doses,
2)
Effectiveness in
subpopulation (s) not considered in the study, &
3)
Potential Impact on community transmission.
Safety
profile that was not initially clear may also appear.
In the US, existing active & passive monitoring
system are being triggered to
closely evaluate safety of SARS-CoV-2 vaccine.
REFERENCES
- World Health Organization. Director-General's remarks
at the media briefing on 2019-nCoV on 11 February 2020.
http://www.who.int/dg/speeches/detail/who-director-general-s-remarks-at-the-media-briefing-on-2019-ncov-on-11-february-2020
(Accessed on February 12, 2020).
- World Health Organization. Draft landscape of COVID-19
candidate vaccines.
https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines
(Accessed on October 20, 2020).
- College of Physicians of Philadelphia. The History of
Vaccines: Vaccine Development, Testing, and Regulation.
https://www.historyofvaccines.org/content/articles/vaccine-development-testing-and-regulation
(Accessed on October 20, 2020).
- Corbett KS,
Flynn B, Foulds KE, et al. Evaluation of the mRNA-1273 Vaccine against
SARS-CoV-2 in Nonhuman Primates. N Engl J Med 2020; 383:1544.
- van
Doremalen N, Lambe T, Spencer A, et al. ChAdOx1 nCoV-19 vaccine
prevents SARS-CoV-2 pneumonia in rhesus macaques. Nature 2020; 586:578.
- Brighton Collaboration. Accelerated Assessment of the
Risk of Disease Enhancement with COVID-19 Vaccines, March 2020.
https://brightoncollaboration.us/brighton-collaboration-cepi-covid-19-web-conference/
(Accessed on October 20, 2020).
- Martin JE,
Louder MK, Holman LA, et al. A SARS DNA vaccine induces neutralizing
antibody and cellular immune responses in healthy adults in a Phase I
clinical trial. Vaccine 2008; 26:6338.
- Lin JT,
Zhang JS, Su N, et al. Safety and immunogenicity from a phase I trial of
inactivated severe acute respiratory syndrome coronavirus vaccine. Antivir
Ther 2007; 12:1107.
- Modjarrad K,
Roberts CC, Mills KT, et al. Safety and immunogenicity of an anti-Middle
East respiratory syndrome coronavirus DNA vaccine: a phase 1, open-label,
single-arm, dose-escalation trial. Lancet Infect Dis 2019; 19:1013.
- Yong CY,
Ong HK, Yeap SK, et al. Recent Advances in the Vaccine Development Against
Middle East Respiratory Syndrome-Coronavirus. Front Microbiol 2019; 10:1781.
COMMENTS