Traditional approach to vaccine development: use of inactivated virus

[cormanr7]

There is a lot of talk about the mRNA based vaccines of Pfizer-BioNTEch and Moderna and the viral vector vaccine of AstraZeneca. Some vaccine developers, however,  have chosen the classical method: grow virus, inactivate it and inject with an adjuvant. Among those are Covavax from Bharat Biotech in India and Coronavac from Sinovac Biotech. in China. A recent article in the hindustan times  https://www.hindustantimes.com/india-news/reading-the-clues-from-covaxin-early-trial-data/story-IdDtQaiU0f6q1PH98sIpgL.html tries to judge the efficacy of Covavax based on interim results from phase I/II trials. Unfortunately, comparison with other products relies mainly on antibody levels which, due to the complex immune response, are difficult to translate into actual level of protection against severe disease. Nevertheless, levels of antibodies for Covavax were comparable to people that had recovered from moderate to severe COVID (as was also the case with the AstraZeneca vaccine) whereas they were much lower for Coronavac. In contrast, the two mRNA vaccines produced two- to four fold higher antibody levels. Turkey yesterday claimed that the Sinovac vaccine had an efficacy of 91% (based on people infected) but the sample size is very small (1,322 persons with 29 infections). They have ordered 50 million doses https://www.reuters.com/article/us-health-coronavirus-turkey-china/turkey-says-chinas-sinovac-covid-vaccine-9125-effective-in-late-trials-idUSKBN28Y1R1.    A larger trial in Brazil of Sinovac gave 'less than 90% but more than 50%' efficacy https://www.bloomberg.com/news/articles/2020-12-25/china-shot-s-efficacy-uncertain-despite-brazil-turkey-results. with more accurate data to be provided later (apparently the Chinese wanted to check if the cases marked as COVID infection conform to their definition, whatever that is). Further trials are conducted in a.o. Indonesia and Chile. Maybe surprisingly, the Sinovac vaccine has been ordered by Singapore.

Without a full disclosure of the data it all remains very murky. This is not helped by the fact that the various trials do not follow common procedures or definitions (i.e. how is efficacy defined?)

[pseudorabies]

I eagerly await one of the vaccines that come out or the US or Europe.  I don't see a scenario where I would get the Chinese vaccine.  This is for a variety of reasons including lack of confidence in the data, quality control and concern over counterfeit vaccines coming out of China. 

 

Also, I don't think it's appropriate that China profits off of this.

[mommysboy]

The vector/attenuated vaccines utilize tried and tested techniques that are still used in vaccines to this very day, but will likely not match the mRNA vaccines.  Perhaps the yardstick of their success is to compare them alongside the well known flu vaccine, which has anywhere between 40 and 60% effectiveness, but is also very successful at limiting the severity of infection.  Astra zeneca has submitted for approval with the MRHA in the UK, and has published peer reviewed studies in the Lancet, and appears to produce an efficacy of at least 62%, as well as performing equally as well as the mRNA vaccines at stopping severe infection.  I suppose we'll have our answer in a few days one way or another.

 

As to the others, they may be better or worse than the AZ vaccine, but without submitting for review to one of the western medicine regulators, or publishing full trial data, then they can't really be considered safe or efficacious, even though they possibly are just as good.

 

Really, only the AZ vaccine at this stage allows for the type of fast, mass inoculation that is really needed right now. So fingers crossed, but it's a bit worrying that we are in this position, and like others I feel AZ let the side down.  It's led to all sorts of cranky rumours.

 

 

 

 

[cormanr7]

18 hours ago, pseudorabies said:

I eagerly await one of the vaccines that come out or the US or Europe.  I don't see a scenario where I would get the Chinese vaccine.  This is for a variety of reasons including lack of confidence in the data, quality control and concern over counterfeit vaccines coming out of China. 

 

Also, I don't think it's appropriate that China profits off of this.

Indeed, but as far as I am aware in all the countries that have rolled out/will soon roll out vaccination, it will be free for their citizens. However, especially with limited supplies you will not be free to choose a vaccine, rather one will be allocated. Should there be private institutes where you pay for a vaccination it might be different but this will probably cost an arm and a leg. So I guess that for many it is either a choice of getting a vaccine chosen by the health administrators or whatever or not getting vaccinated at all.    

[mommysboy]

10 hours ago, cormanr7 said:

Indeed, but as far as I am aware in all the countries that have rolled out/will soon roll out vaccination, it will be free for their citizens. However, especially with limited supplies you will not be free to choose a vaccine, rather one will be allocated. Should there be private institutes where you pay for a vaccination it might be different but this will probably cost an arm and a leg. So I guess that for many it is either a choice of getting a vaccine chosen by the health administrators or whatever or not getting vaccinated at all.    

 

Well, maybe that's for the best.  But in the USA 90% plus will be inclined to go for the USA vaccines, and the Government will want that anyway.  And the same principle will apply in the UK- I for instance, as a Brit, want the AZ vaccine if it gets approval.  And yes you're right we'll likely be getting what is offered.

 

It wouldn't surprise me if the big global players will be AZ and Sino vaccines, but if either falls short then attention will turn to J and J, plus a number of others under development.