Please ensure Javascript is enabled for purposes of website accessibility

6 Months Later, Pfizer and BioNTech's Vaccine Data Continues to Impress

By Brian Orelli, PhD and Keith Speights - May 9, 2021 at 7:34AM

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More

Investors should be focused on long-term data.

Pfizer (PFE 3.77%) and BioNTech (BNTX 1.11%) recently disclosed six-month efficacy for their COVID-19 vaccine. In this video from Motley Fool Live, recorded on April 5, Fool.com Contributors Brian Orelli and Keith Speights discuss why investors and patients shouldn't be worried about a slight drop in efficacy. They also discuss the likelihood of getting severe disease -- it's low no matter whose definition you use -- and also talk about the vaccine's ability to protect against the South African variant.

Brian Orelli: Our first story is about Pfizer and BioNTech. They reported updated data on their phase 3 clinical trial. The efficacy went down from 95% when it was first reported to a 91.3% when looking up to six months after the second dose. They had 100% efficacy in preventing severe disease, if you define it by the CDC's definition of severe disease, and it was 95.3% if you use the FDA's definition of severe disease. Then there was 100% efficacy at preventing the South African variant, although that was only six cases. Six versus zero, so I don't think we can quite call it 100% yet. Should we be worried about the dip in efficacy and any other thoughts on the data?

Keith Speights: No, there is no reason at all to worry about the lower overall efficacy. Like you said, Brian, Pfizer and BioNTech, in these updated results, they were measuring up to six months after the second dose. That initial efficacy result of 95% was much closer to the administration of the second dose of the vaccine. So you would expect maybe a little bit of degradation there, and that's what we're seeing. Nothing big, just a few percentage points, so no reason at all to worry.

Look, this vaccine remains highly effective from everything we can tell. In my view anyway, the most important numbers are still the efficacy in preventing severe disease of COVID-19. Those numbers remain really good, whichever definition you use, whether it's the FDA definition which gives it a 95.3% efficacy or the CDC's definition of severe disease, it gives it 100% efficacy. Look, those are great numbers either way.

That 100% efficacy against the South African variant rather is encouraging. But like you said, there's some really low numbers involved in this study. I think there were only 800 participants in the South African study that Pfizer and BioNTech conducted, that's not an awfully large number of participants in a clinical study and only nine cases of COVID in total were observed in that study in South Africa, six of those were the South African variant and all of those cases occurred in the placebo group. It's very encouraging to see that kind of result against this South African variant. Still early, but I think Pfizer and BioNTech walked away from this latest update feeling pretty good about the vaccine.

Orelli: I'd definitely like to see more data on the variants, but besides that, we're missing data, which they just can't give us, at least not yet. I think the rest of the data looked really positive.

Speights: Right, I agree.

Brian Orelli, PhD has no position in any of the stocks mentioned. Keith Speights owns shares of Pfizer. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.

Invest Smarter with The Motley Fool

Join Over 1 Million Premium Members Receiving…

  • New Stock Picks Each Month
  • Detailed Analysis of Companies
  • Model Portfolios
  • Live Streaming During Market Hours
  • And Much More
Get Started Now

Stocks Mentioned

Pfizer Inc. Stock Quote
Pfizer Inc.
PFE
$50.11 (3.77%) $1.82
BioNTech SE Stock Quote
BioNTech SE
BNTX
$160.35 (1.11%) $1.76

*Average returns of all recommendations since inception. Cost basis and return based on previous market day close.

Related Articles

Motley Fool Returns

Motley Fool Stock Advisor

Market-beating stocks from our award-winning analyst team.

Stock Advisor Returns
389%
 
S&P 500 Returns
125%

Calculated by average return of all stock recommendations since inception of the Stock Advisor service in February of 2002. Returns as of 08/12/2022.

Discounted offers are only available to new members. Stock Advisor list price is $199 per year.

Premium Investing Services

Invest better with The Motley Fool. Get stock recommendations, portfolio guidance, and more from The Motley Fool's premium services.