Covid-19 Booster Data is Out, Not Great
Pfizer Phase 3 Clinical Trial Data for Boosters is Underwhelming
This is from the Pfizer press release (at the bottom) about the "booster shot" clinical trial that was performed. The full report has not been released, but this is what was released today from Pfizer. Let's dissect this a little bit. Please comment is anything is wrong with my math or assumptions so that I can correct.
1) The control group was about 10,000 fully vaccinated (two shots) people. I am assuming half in the placebo group and half in the booster group for 5,000 in each group.
2) They started the data collection 7 days after the booster or placebo jab. Then looked at who tested positive for Covid at any point from that day to 2.5 months later.
3) In the placebo (fully vaccinated) group there were 109 cases out of 5,000 or 2.2%. This means that fully vaccinated people are catching Covid at a rate of 2.2% per 2.5 months or 10.5% per year. This means if you are fully vaccinated you have a 10.5% chance of catching Covid this year. This means the initial vaccine does not work very well.
4) The booster group had 5 cases out of 5,000 or 0.1% per 2.5 months or 0.5% per year. This sounds like a good reduction, but this is if we assume that there is no waning of the "booster" shot protection. If the booster is anything like the original dose, the effects will wane at a rate of 40% per month. It should be mentioned that the original two doses Phase 3 clinical trial had 8 cases out of 22,000 or 0.0003% at the same approximate 2.5 month mark. This means the "booster plus 2" as an overall effectiveness (though you are technically fully vaccinated) is 333 times less effective than the original dose at 2.5 months.
5) The original dose press release has cases of "severe Covid". This data was not in the booster dose press release, but it was in the original dose press release. I am curious to see that portion of data. In the original data there was 1 severe out of 8 cases in vaccinated (12.5%) and 9 out of 162 in unvaccinated group (5.5%).
6) We know in the original Phase 3 study the six month data had 87 cases as opposed to the 8 cases in the two and half month data. This means that 79 of the cases were from 2.5 month to 6 month. I wonder if this increase in absolute cases is the reason Pfizer unblinded the study at 6 months when it was originally supposed to be a 24 month study. This means overall effectiveness is 8/22,000 or 0.0003% at 2.5 months, 87/22,000, at 6 months or 0.004% at 6 months, and 109/5,000 or 2.2% at 11-13.5 months. Not a good trend. Let's hope the booster protection shot doesn't wear off as fast.
Quote from Pfizer Press release
"Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) today announced topline results from a Phase 3 randomized, controlled trial evaluating the efficacy and safety of a 30-µg booster dose of the Pfizer-BioNTech COVID-19 Vaccine in more than 10,000 individuals 16 years of age and older. In the trial, a booster dose administered to individuals who previously received the Pfizer-BioNTech primary two-dose series restored vaccine protection against COVID-19 to the high levels achieved after the second dose, showing a relative vaccine efficacy of 95.6% when compared to those who did not receive a booster. These are the first efficacy results from any randomized, controlled COVID-19 vaccine booster trial. All trial participants previously completed the primary two-dose series of the Pfizer-BioNTech vaccine, and then were randomized 1:1 to receive either a 30-µg booster dose (the same dosage strength as those in the primary series) or placebo. The median time between second dose and administration of the booster dose or placebo was approximately 11 months. Symptomatic COVID-19 occurrence was measured from at least 7 days after booster or placebo, with a median follow-up of 2.5 months. During the study period, there were 5 cases of COVID-19 in the booster group, and 109 cases in the non-boosted group. The observed relative vaccine efficacy of 95.6% (95% CI: 89.3, 98.6) reflects the reduction in disease occurrence in the boosted group versus the non-boosted group in those without evidence of prior SARS-CoV-2 infection. Median age of participants was 53 years, with 55.5% of participants between 16 and 55 years, and 23.3% of participants 65 years and older. Multiple subgroup analyses showed efficacy was consistent irrespective of age, sex, race, ethnicity, or comorbid conditions." From Press Release
Link to the original 2.5 month press release according to Pfizer.
https://www.businesswire.com/news/home/20201118005595/en/
Link to the booster 2.5 month press release according to Pfizer.