COVID-19 Vaccine Update

I’ve been wanting to give an update on vaccines, so this will be a large post giving an update on the recent happenings.

Reminder that this is an mRNA vaccine, requiring cold storage at -20C. Today they released (by press) their primary efficacy data that showed of 196 COVID-19 cases, of which 185 were in placebo group and 11 in the vaccine group; giving it an efficacy of 94.1%. Importantly, all 30 severe COVID-19 cases were in the placebo group. There was one COVID-19 death in the placebo group. Study included 30,000 participants.

In terms of safety, the most common solicited adverse reactions included injection site pain, fatigue, myalgia, arthralgia, headache, and erythema/redness at the injection site.



This is also an mRNA vaccine, requiring cold storage at -70C. Last week they released (by press) primary efficacy analysis that showed the vaccines had a 95% efficacy against COVID-19. There were 170 confirmed cases of COVID-19 with 162 in the placebo group and 8 in the vaccine group. Importantly, efficacy was consistent across age, gender, race and ethnicity demographics and observed efficacy in adults >65 years of age was over 94%. Study included a total of 43,000 participants.

In terms of safety, the vaccine was well tolerated across all populations, no serious safety concerns observed and the only Grade 3 adverse event greater than 2% in frequency was fatigue at 3.8% and headache at 2.0%.



This one is a little complicated. Reminder that this is not an mRNA, but in fact a vaccine using a weakened adenovirus as a vector, requiring only refrigeration at 2-8C.

Last week, they also released (by press)results from an interim analysis. One dosing regimen (n=2,741) showed vaccine efficacy of 90% when the vaccine was given as a half dose, followed by a full dose at least one month apart. The second dosing regimen (n=8,895) showed 62% efficacy when given as two full doses at least one month apart. The combined analysis from both dosing regimens (n=11,636) resulted in an average efficacy of 70%. It was later released on an investor call that the half-dose regimen was, in fact, a dosing error and that the secondary analysis including this was not pre-specified. This raises some serious limitations in data validity and the sample size of the dosing error group is very small.

I am also going to refrain from discussing the safety profile as I do not feel the company has been transparent with the cases from earlier this year that resulted in brief halts in the trial. The company does state in their above press release that “no serious safety events related to the vaccine have been confirmed”.


???? ?????:

Pfizer, with the -70C cold chain requirement has a process for delivery where the vaccines come in transport boxes packed with dry ice that can allow the vaccines to remain within those for up to 30 days. In addition, the Canadian Covid-19 Vaccine Taskforce is  working on purchasingmore than 100 freezers to store both the Moderna and Pfizer vaccines.



Moderna and Pfizer have applied to the U.S. FDA for Emergency Use Authorization. Both also have rolling submissions in place for Health Canada. What this means is that it allows for submission of materials as they are available instead of waiting for everything to be done before submitting – this allows for significant time savings. Both are anticipated to get approval before the end of the year.
??? ?????????? ??????????? ??? ?? ???????? ?????? ???? ?? ?????-?? ????????: