An article published today on Reuters and elsewhere reads, “Israeli survey finds 3rd Pfizer vaccine dose has similar side effects to 2nd.” Buried within this article is the following:
About 0.4% said they suffered from difficulty breathing, and 1% said they sought medical treatment due to one or more side effect.
This seemed quite bad to me and like a worrisome result. I sought information on how many sought medical treatment after the second shot. I could not find this information, but I did find:
only 51 of some 650,000 people to have received the Pfizer shot sought medical attention for symptoms suffered
from a December 2020 article on Israeli vaccination. Comparing the 1% to 51⁄650000 = 0.008% I found that the current frequency of side effects requiring medical attention was 128x the level found after dose 1. This seemed like a bad sign.
I then sought out more information about side effects post dose 2 in Israel, which I did not find. But instead I looked at the CDC’s Advisory Committee on Immunization Practices’ Interim Recommendation for Moderna, and found the following:
The frequency of serious adverse events** observed was low in both the vaccine (1.0%) and placebo (1.0%) recipients
** Serious adverse events are defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, or results in persistent disability/incapacity.
I can’t believe that this was 1%! That seems surprisingly high (for either group). I expect the outside-of-trial data has not been nearly that magnitude.
This 1% matches the current Israeli data, and with a more restrictive definition, so the Israeli data no longer seems particularly worrisome in comparison, though I may dig in to this further. In general, I feel somewhat confused by the situation.
With such highly subjective soft outcomes a lot depends on the way the question is phrased and interpreted (if self-reporting). Thus comparing different populations and studies is almost impossible without really carefully digging into the original publications and even then it is fraught with problems.
If I have a rash post-vaccine and I go to see my GP or pharamcist, am I seeking medical help and is this worrisome? If I get up and later realize that I need to lie down or else I will faint (vasovagal syncope, around one in ten people have some form of needle phobia), am I seeking medical help for a side-effect? Technically yes, but a saline injection would cause the same. If I have asthma or hayfever, issues with breathing, and later misattribute this to the vaccine, is this a side-effect? (around 1 in 10 people or so have asthma)
Finally, you cannot compare the serious side-effects in a trial (if this CDC figure really comes from a trial) with mild self-reported side-effects from Israel or American postmarketing surveillance. Trial participants will be monitored closely and will include a large number of at risk indiviudals (>60yo) so it is again a statistical artifact of data collection.
IMHO all the data is worthless without a very well-matched control group.
An article published today on Reuters and elsewhere reads, “Israeli survey finds 3rd Pfizer vaccine dose has similar side effects to 2nd.” Buried within this article is the following:
This seemed quite bad to me and like a worrisome result. I sought information on how many sought medical treatment after the second shot. I could not find this information, but I did find:
from a December 2020 article on Israeli vaccination. Comparing the 1% to 51⁄650000 = 0.008% I found that the current frequency of side effects requiring medical attention was 128x the level found after dose 1. This seemed like a bad sign.
I then sought out more information about side effects post dose 2 in Israel, which I did not find. But instead I looked at the CDC’s Advisory Committee on Immunization Practices’ Interim Recommendation for Moderna, and found the following:
I can’t believe that this was 1%! That seems surprisingly high (for either group). I expect the outside-of-trial data has not been nearly that magnitude.
This 1% matches the current Israeli data, and with a more restrictive definition, so the Israeli data no longer seems particularly worrisome in comparison, though I may dig in to this further. In general, I feel somewhat confused by the situation.
Sources: Reuter’s article from today—https://www.reuters.com/business/healthcare-pharmaceuticals/israeli-survey-finds-3rd-pfizer-vaccine-dose-has-similar-side-effects-2nd-2021-08-08/
Article from December 2020 - https://www.timesofisrael.com/1-in-1000-israelis-report-mild-side-effects-from-vaccine/
CDC’s Advisory Committee on Immunization Practices’ Interim Recommendation for Moderna: https://www.cdc.gov/mmwr/volumes/69/wr/mm695152e1.htm
EDIT: This article’s statistics contrast with those of Reuter’s, and show data very similar to the 1st shot: https://www.timesofisrael.com/of-600000-israelis-who-received-3rd-dose-fewer-than-50-reported-side-effects/
With such highly subjective soft outcomes a lot depends on the way the question is phrased and interpreted (if self-reporting). Thus comparing different populations and studies is almost impossible without really carefully digging into the original publications and even then it is fraught with problems.
If I have a rash post-vaccine and I go to see my GP or pharamcist, am I seeking medical help and is this worrisome? If I get up and later realize that I need to lie down or else I will faint (vasovagal syncope, around one in ten people have some form of needle phobia), am I seeking medical help for a side-effect? Technically yes, but a saline injection would cause the same. If I have asthma or hayfever, issues with breathing, and later misattribute this to the vaccine, is this a side-effect? (around 1 in 10 people or so have asthma)
Finally, you cannot compare the serious side-effects in a trial (if this CDC figure really comes from a trial) with mild self-reported side-effects from Israel or American postmarketing surveillance. Trial participants will be monitored closely and will include a large number of at risk indiviudals (>60yo) so it is again a statistical artifact of data collection.
IMHO all the data is worthless without a very well-matched control group.