Wednesday 26 August 2020

Coronavirus (20) The race to develop COVID-19 vaccines

Five months have passed since the characterization of COVID-19 as a pandemic by the WHO on 11th March. You may wonder how much progress is being made in developing vaccines specifically for COVID-19. Let us have a look at a report by the WHO that provides data on all the COVID-19 candidate vaccines that are being developed in the world.1

According to the latest data from WHO (20th August), there are 169 candidate vaccines being developed for COVID-19 prevention, of which 139 are in *preclinical evaluation and 30 are in *clinical evaluation. Eleven countries are at the forefront of the race to develop vaccines: among the vaccines in clinical stages, 6 are from China, 4 from the US, 2 from the UK, 2 from India, and one each from Germany, Japan, South Korea, Belgium, Cuba, Singapore, Canada and Russia. The other 8 candidate vaccines which are in the clinical evaluation stages are jointly developed by research institutes and/or pharmaceutical companies from different countries; adding these 8 candidate vaccines causes Italy, France, Australia and Taiwan to be among the contestants in the race to develop a COVID-19 vaccine.

There are some encouraging points to note. Among the 30 candidate vaccines in clinical evaluation, six are already in phase 3, the last phase of clinical trials. China, where COVID-19 first originated, has 3 candidate vaccines already entered into phase 3, plus one vaccine (BNT162b1) which is jointly developed with Pfizer (a worldwide pharmaceutical company with headquarters in the US) is also in phase 3 of clinical trials. The vaccine (AZD1222) co-developed by the University of Oxford and AstraZeneca in the UK, and the mRNA vaccine (mRNA-1273) developed by Moderna in the US, are also in phase 3 of clinical trials.

Although the speed of global vaccine development is already high, the chief medical officer of England, Professor Whitty, said in an interview on 23rd August that he would be "quite surprised if we had a highly effective vaccine ready for mass use in a large percentage of the population before the end of winter, certainly [not] this side of Christmas".2 We should not anticipate that the vaccine for COVID-19 will be available this year. This reflects the fact that phase 3 of clinical trials usually takes a much longer time, than the other initial phases, and usually lasts for several years as more volunteers are needed and the safety requirements are more stringent.

An interesting point to note is that a tobacco company, Kentucky Bioprocessing, Inc., in the US is one of the leading contestants in developing a COVID-19 vaccine. The vaccine candidate they developed has already finished phase 1 and is now in phase 1/2 of clinical trials. In fact, when we look at their website, we can understand that this is not a pure tobacco selling company. It plants tobacco to express, extract and purify proteins for use in vaccines and other pharmaceuticals.3

The traditional vaccines developed in the early 20th century are virus-based and are either live-attenuated or inactivated. However, in the race for COVID-19 vaccine development, we can see a much greater variety of vaccine platforms being used. Other than the traditional platform, different viral vectors, nucleic acid-based vaccines, and antigen-presenting cells are also among the vaccine candidates in the clinical stages. I am going to introduce you the 30 candidate vaccines for COVID-19 which are in clinical evaluation, based on their vaccine platforms, in the next blog posts.



*Preclinical evaluation is the analytical results from testing of the toxicity and efficacy of a medication, vaccine in this case, using human cell cultures or animal models in the laboratory.

Clinical evaluation is the assessment and analysis of clinical data collected from clinical trials. Clinical trials are performed, if the result from preclinical research is promising, to see how well the vaccine works in humans. Clinical trials happen in 3 phases, each phase building on the results of previous phases and recruiting more volunteer participants. Clinical studies to demonstrate the safety and efficacy of vaccines must be conducted in humans before a vaccine can be released for widespread use.



References
1. Draft landscape of COVID-19 candidate vaccines. World Health Orgainzation. 20 August 2020. https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines
2. Coronavirus: Missing school is worse than virus for children - Whitty. BBC news, UK. 23 August, 2020. https://www.bbc.co.uk/news/uk-53875410
3. Home page of Kentucky Bioprocessing, Inc. (KBP). https://kentuckybioprocessing.com/


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