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I've been reading about the Pfizer clinical trial data for their COVID-19 vaccine today, so I'm gonna write a thread about what I learned.
Overall, remarkable safety and efficacy.
Here we go!
Overall, remarkable safety and efficacy.
Here we go!
The vaccine is shipped as a multi-dose vial, frozen between -80 and -60C, and it has to be thawed and reconstituted with a sterile saline solution.
The vaccine does not have any preservative (one less topic we need to rehash with vax hesitant people....)
The vaccine does not have any preservative (one less topic we need to rehash with vax hesitant people....)
The most common side effects reported:
- Injection site rx (84%)
- Fatigue (63%)
- Headache (55%)
- Muscle pain (38%)
- Chills (32%)
- Joint pain (24%)
- Fever (14%)
- Injection site rx (84%)
- Fatigue (63%)
- Headache (55%)
- Muscle pain (38%)
- Chills (32%)
- Joint pain (24%)
- Fever (14%)
The frequency of serious side effects was low (less than 0.5%) and there was no meaningful difference overall between those who got the vaccine vs. those who got a saline placebo with regards to serious side effects.
The RNA in the vaccine was modified (probably replacement of U w/ 1-methylpseudouridine, naturally occurring) to allow the RNA to stick around for a few days and to prevent immune reactions that had plagued early RNA vaccines a few decades ago.
It turns out the "letters" used in RNA (A,U,C,G) can be chemically modified in the body (100 mods are known). Scientists found a combo that made this RNA more stable and much less likely to trigger undesirable immune reaction.
Effectiveness: 95%, meaning 8 people who got the vaccine went on to develop lab-confirmed COVID at least 7 days after last dose vs. 162 who got the placebo.
There were very, very few cases of severe COVID illness: 1 who got the vaccine, 3 who got the placebo.
Enlarged lymph nodes, plausibly related to vaccination, were palpated in 64 who got vaccine vs. 6 who got the placebo.
4 in vax group developed temporary weakness or paralysis of facial muscles, though in keeping with what's expected in gen pop (does occur outside of vax trials)
4 in vax group developed temporary weakness or paralysis of facial muscles, though in keeping with what's expected in gen pop (does occur outside of vax trials)
How many withdrew during the study because of side effects?
37 in the vaccine arm.
30 in the placebo arm.
They did not know in which arm they were, as the study was blinded.
37 in the vaccine arm.
30 in the placebo arm.
They did not know in which arm they were, as the study was blinded.
Deaths? 2 in the vaccine group (cardiac arrest and arteriosclerosis), 4 in the placebo group. Rates comparable to general population.
In terms of benefits, we know immunity lasts at least 2 months. Beyond that, unknown. Effectiveness for asymptomatic infection and to prevent transmission of the virus: unknown.
In terms of risks, we need more participants under the age of 16, pregnant, or immunocompromised to have reliable safety data in these subgroups.
We won't know about very, very rare side effects (but you never do in a clinical trial).
We won't know about very, very rare side effects (but you never do in a clinical trial).
Also, available data do not indicate a risk of vaccine-enhanced disease, but this risk over time remains unknown and needs to be evaluated further.
Overall, Pfizer's vaccine looks incredibly effective, quite safe, and fairly well tolerated. We should expect a fair amount of temporary sore arms, fatigue and headaches.
This vaccine is a scientific achievement.
I'll be reading what experts have to say about the data soon!
This vaccine is a scientific achievement.
I'll be reading what experts have to say about the data soon!
2 medical staffers who got the Pfizer vaccine developed an allergic reaction. They had a history of this sort of thing.
"Regulator’s advice says that any person with a history of significant allergic reactions to vaccines, medicine or food should not receive the Pfizer vaccine."
"Regulator’s advice says that any person with a history of significant allergic reactions to vaccines, medicine or food should not receive the Pfizer vaccine."
Full story here: https://time.com/5919258/pfizer-vaccine-allergies/
As I search for "allerg*" and "anaph*" in the FDA report on the vaccine, not much to find.
Excerpt in next tweet.
Excerpt in next tweet.
"A slight numerical imbalance of adverse events potentially representing allergic reactions, with more participants reporting hypersensitivity-related adverse events in the vaccine group (137 [0.63%]) compared with the placebo group (111 [0.51%])."
