Continued from my last blog post.
3. Inactivated vaccine by the Institute of Medical Biology at the Chinese Academy of Medical Sciences (IMBCAMS)
The inactivated vaccine for COVID-19 developed by the Institute of Medical Biology at the Chinese Academy of Medical Sciences (IMBCAMS) started its phase 1-2 clinical trial in early July (NCT04470609), targeting 471 healthy volunteers aged above 60 in China.1
According to the study design, it seems that the vaccine needs two injections, as with the other inactivated vaccines candidates. The enrolled subjects in phase 1 receive two doses of low-, medium-, or high-dose experimental vaccines, or placebo, at an interval of 28 days, while the enrolled subjects in phase 2 receive two doses of medium or high-dose experimental vaccines, or placebo, at an interval of 28 days. Information from ClinicalTrials.gov under the NIH of the USA indicates that the clinical trial is still ongoing and no study results have yet been published.
4. CovaxinTM by Bharat Biotech International Ltd.
CovaxinTM is the India's first indigenous COVID-19 vaccine.2 It is co-developed by Bharat and the Indian Council of Medical Research (ICMR)-National Institute of Virology (NIV).
The vaccine received approval from India's regulatory agency for phase 1&2 human clinical trials, which have commenced across India since July.3 The study (NCT04471519) aims to recruit 1125 healthy volunteers, 375 in phase 1 and 750 in phase 2, to receive two intramuscular doses of the vaccine formulations 14 days apart. Information from ClinicalTrials.gov under the NIH of the USA indicates that the clinical trial is still ongoing and no study results have yet been published.3
Bharet Biotech sells vaccines of various platforms, including the inactivated vaccines, live-attenuated vaccines, and recombinant vaccines. The company has much experience in producing inactivated vaccines. Currently, they are selling 6 inactivated vaccine products which include vaccines for diphtheria, tetanus, pertussis, influenza A (H1N1), rabies, and Japanese Encephalitis. The development of an inactivated vaccine for COVID-19 is expected to show the company's ability to develop safe and high-efficacy vaccines.
Conclusion
Inactivated vaccine is one of the classic vaccine techniques. By using a denaturing agent, the infectious particles are denatured such that they can retain enough of their protein surfaces to set off a useful immune response. However, the tricky part of developing of an inactivated vaccine is the balance between inactivating the virus enough so that it cannot infect cells but not inactivate so much that it presents a totally different protein to the immune system and raises a response that cannot recognize the real virus.4 Therefore, the key to success relies on experience in development of inactivated vaccines which have been brought into the market. The biotech companies with products of inactivated vaccines on the market should have a higher chance of developing a COVID-19 vaccine with high efficacy and meeting safety standards.
Under normal conditions, the inactivated vaccine is more stable than RNA and other vaccine prototypes. According to the CEO of Sinovac, their inactivated vaccine against COVID-19, CoronaVac, has a shelf life of 3 years.5 The ease of preserving a vaccine cheaply means it can be more affordable in less-developed countries, and that distribution to a far-flung population is much less a problem.
However, it should be noted that inactivated vaccines do not generally provide protection as strong as live-attenuated vaccines, that is, weakened forms of pathogens. This is because inactivated vaccines are less like the natural infections than are the live-attenuated vaccines. Usually, at least 2 doses of the vaccine are required to provide sufficient protection. All 5 of the forefront inactivated vaccines mentioned in this blog required second injections.
References
1. https://web.archive.org/web/20200909094043/https://clinicaltrials.gov/ct2/show/record/NCT04470609
2. Bharat Biotech's website on Covaxin: https://www.bharatbiotech.com/covaxin.html
3. https://web.archive.org/web/20200909113422/https://clinicaltrials.gov/ct2/show/study/NCT04471519
4. SinoPharm's inactivated coronavirus vaccine. Derek Lowe. Science Translational Medicine. https://blogs.sciencemag.org/pipeline/archives/2020/08/17/sinopharms-inactivated-coronavirus-vaccine
5. "We will share our vaccine with the world." Inside the Chinese biotech firm leading the fight against COVID-19. Charlie Campbell. Time, 27 July, 2020. https://time.com/5872081/sinovac-covid19-coronavirus-vaccine-coronavac/
3. Inactivated vaccine by the Institute of Medical Biology at the Chinese Academy of Medical Sciences (IMBCAMS)
The inactivated vaccine for COVID-19 developed by the Institute of Medical Biology at the Chinese Academy of Medical Sciences (IMBCAMS) started its phase 1-2 clinical trial in early July (NCT04470609), targeting 471 healthy volunteers aged above 60 in China.1
According to the study design, it seems that the vaccine needs two injections, as with the other inactivated vaccines candidates. The enrolled subjects in phase 1 receive two doses of low-, medium-, or high-dose experimental vaccines, or placebo, at an interval of 28 days, while the enrolled subjects in phase 2 receive two doses of medium or high-dose experimental vaccines, or placebo, at an interval of 28 days. Information from ClinicalTrials.gov under the NIH of the USA indicates that the clinical trial is still ongoing and no study results have yet been published.
4. CovaxinTM by Bharat Biotech International Ltd.
CovaxinTM is the India's first indigenous COVID-19 vaccine.2 It is co-developed by Bharat and the Indian Council of Medical Research (ICMR)-National Institute of Virology (NIV).
The vaccine received approval from India's regulatory agency for phase 1&2 human clinical trials, which have commenced across India since July.3 The study (NCT04471519) aims to recruit 1125 healthy volunteers, 375 in phase 1 and 750 in phase 2, to receive two intramuscular doses of the vaccine formulations 14 days apart. Information from ClinicalTrials.gov under the NIH of the USA indicates that the clinical trial is still ongoing and no study results have yet been published.3
Bharet Biotech sells vaccines of various platforms, including the inactivated vaccines, live-attenuated vaccines, and recombinant vaccines. The company has much experience in producing inactivated vaccines. Currently, they are selling 6 inactivated vaccine products which include vaccines for diphtheria, tetanus, pertussis, influenza A (H1N1), rabies, and Japanese Encephalitis. The development of an inactivated vaccine for COVID-19 is expected to show the company's ability to develop safe and high-efficacy vaccines.
Conclusion
Inactivated vaccine is one of the classic vaccine techniques. By using a denaturing agent, the infectious particles are denatured such that they can retain enough of their protein surfaces to set off a useful immune response. However, the tricky part of developing of an inactivated vaccine is the balance between inactivating the virus enough so that it cannot infect cells but not inactivate so much that it presents a totally different protein to the immune system and raises a response that cannot recognize the real virus.4 Therefore, the key to success relies on experience in development of inactivated vaccines which have been brought into the market. The biotech companies with products of inactivated vaccines on the market should have a higher chance of developing a COVID-19 vaccine with high efficacy and meeting safety standards.
Under normal conditions, the inactivated vaccine is more stable than RNA and other vaccine prototypes. According to the CEO of Sinovac, their inactivated vaccine against COVID-19, CoronaVac, has a shelf life of 3 years.5 The ease of preserving a vaccine cheaply means it can be more affordable in less-developed countries, and that distribution to a far-flung population is much less a problem.
However, it should be noted that inactivated vaccines do not generally provide protection as strong as live-attenuated vaccines, that is, weakened forms of pathogens. This is because inactivated vaccines are less like the natural infections than are the live-attenuated vaccines. Usually, at least 2 doses of the vaccine are required to provide sufficient protection. All 5 of the forefront inactivated vaccines mentioned in this blog required second injections.
References
1. https://web.archive.org/web/20200909094043/https://clinicaltrials.gov/ct2/show/record/NCT04470609
2. Bharat Biotech's website on Covaxin: https://www.bharatbiotech.com/covaxin.html
3. https://web.archive.org/web/20200909113422/https://clinicaltrials.gov/ct2/show/study/NCT04471519
4. SinoPharm's inactivated coronavirus vaccine. Derek Lowe. Science Translational Medicine. https://blogs.sciencemag.org/pipeline/archives/2020/08/17/sinopharms-inactivated-coronavirus-vaccine
5. "We will share our vaccine with the world." Inside the Chinese biotech firm leading the fight against COVID-19. Charlie Campbell. Time, 27 July, 2020. https://time.com/5872081/sinovac-covid19-coronavirus-vaccine-coronavac/
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