So.. just how good are the different vaccines? Note that you can’t reeeeally do a straight comparison of one vax to another because the trials measured different things with different populations and different variant mixes at different times. As a good article in The Economist says, “the gap in reported efficacy may say more about the trials than about the vaccines themselves.”
Not only that, but some trials had such low numbers of severe cases even in the placebo branch that it was really hard to draw good conclusions.
With that disclaimer, I present data below. Also, this review article from 25 September 2021 has a very exhaustive list.
|Brand||Against||Where||First shot+M||Second Shot+N|
|Pfizer||infection||Israel / HCW||52·4%||90.5%|
|Pfizer||infection||UK / HCW||72%||86%|
|AZ||symptomatic||South Africa B.1.351||x||10.6%|
|Sinopharm||hospitalization||Bahrain, UAE, Egypt, Jordan||x||78.7%|
|CoronaVac||infection||Brazil / Sao Paolo||x||51.8-70%|
|Pfizer||hospitalization over 80 y/o||UK||81%||93%|
|AZ||hospitalization over 80 y/o||UK||73%||x|
|Pfizer or AZ||hospitalization over 70 y/o||UK||84%||81%|
|Johnson & Johnson||infection||USA||76.7%||N/A|
|Johnson & Johnson||moderate illness||USA||72%||N/A|
|Johnson & Johnson||infection||South Africa||52%||N/A|
|Johnson & Johnson||mild to moderate illness||South Africa||64%||N/A|
|Johnson & Johnson||severe illness||South Africa||82%||N/A|
|Johnson & Johnson||moderate illness||Brazil||66.2%||N/A|
|Johnson & Johnson||mild to moderate illness||Brazil||68%||N/A|
|Johnson & Johnson||severe illness||Brazil||88%||N/A|
|Pfizer or Moderna||infection||Ontario||48-71%||91%|
|Pfizer or Moderna||severe||Ontario||62-91%||98%|
|Sputnik V||symptomatic infection ages 60-79||Argentina||x||78.6%|
|Sputnik V||hospitalization ages 60-79||Argentina||x||87.6%|
|Sputnik V||deaths ages 60-79||Argentina||x||84.7%|
|mRNA||any infection||US HCW (CDC)||81%||91%|
|Soberana||infection? dose 2 out of 3 PRELIM||Cuba?||62%|
|Abdala||infection? 3 out of 3 PRELIM||Cuba?||92.3%|
|Pfizer||hospitalization of over 80 y/os||UK||79·3%||N/A|
|AZ||hospitalization of over 80 y/os||UK||80·4%||N/A|
|Pfizer||all asymptomatic||Israel HCW||65.1%|
|Pfizer||infectious asymptomatic||Israel HCW||69.6%|
|Pfizer||all symptomatic||Israel HCW||89.7%|
|Pfizer||infectious symptomatic||Israel HCW||88.1%|
|AZ||asymptomatic infection in high-risk groups||England||60%||81%|
|Pfizer||symptomatic infection in high-risk groups||England||60%|
|Pfizer||symptomatic infection in high-risk groups over 65||England||89%|
|AZ||symptomatic infection in high-risk groups over 65||England||80%|
|AZ/Pfizer||symptomatic infection in immunosuppressed||England||4%||74%|
|Pfizer||symptomatic in age 16-64||UK||48.6%||93.3%|
|AZ||symptomatic in age 16-64||UK||50.2%||78.0%|
|Pfizer||symptomatic in age 65+||UK||56.6%||86.7%|
|AZ||symptomatic in age 65+||UK||60.9%||76.4%|
|Pfizer||symptomatic in immunosuppressed||UK||15.9%||73.0%|
|AZ||symptomatic in immunosuppressed||UK||43.9%||74.6%%|
|mRNA||hospitalization, 18-49 y/o||US||97.3%|
|mRNA||hospitalization in immunosuppressed||US||59.2%|
|Pfizer||asymptomatic infection in pregnant||Israel||67%, 71%||97%|
|Pfizer||symptomatic in pregnant||Israel||66%, 76%||97%|
|Pfizer||hospitalization in pregnant||Israel||89%|
|Pfizer||symptomatic in all veterans||US||84.0%||96.25|
|Moderna||symptomatic in all veterans||US||85.7%||98.2%|
|Pfizer 6 month study||symptomatic 7 days to 2 months post dose2||US / South Africa / Brazil / Argentina / Germany / Turkey||91.1%||96.2%|
|Pfizer 6 month study||symptomatic at 4-6 months post dose2||US / South Africa / Brazil / Argentina / Germany / Turkey||83.7%|
6 month study
|severe||US / South Africa / Brazil / Argentina / Germany / Turkey||96.7%|
|AZ||asymptomatic to household contacts||Netherlands||58%|
|Pfizer||asymptomatic to household contacts||Netherlands||70%|
|Moderna||asymptomatic to household contacts||Netherlands||88%|
|J&J||asymptomatic to household contacts||Netherlands||77%|
|Moderna||asymptomatic infection||Southern California||72.7%|
|Johnson & Johnson||infection, corrected for under-reporting||USA||79%|
|Johnson & Johnson||infection, not corrected for under-reporting||USA||69%|
|Johnson & Johnson||hospitalization, corrected for under-reporting||USA||81%|
|Johnson & Johnson||hospitalization, not corrected for under-reporting||USA||73%|
|Johnson & Johnson||symptomatic infection||USA||94%|
|Johnson & Johnson||symptomatic infection||world outside USA||75%|
|Johnson & Johnson||hospitalization||many countries||100%|
|Pfizer||symptomatic infection||USA, health care workers||77.6%||88.8%|
|Moderna||symptomatic infection||USA, health care workers||88.9%||96.3%|
|Clover||infection||Philippines, Colombia, South Africa, Brazil, Belgium||79%|
|Clover||hospitalization||Philippines, Colombia, South Africa, Brazil, Belgium||100%|
|Moderna||5-month followup, asymptomatic infection||USA, high-risk individuals||63.0%|
|Moderna||5-month followup, symptomatic infection||USA, high-risk individuals||93.2%|
|Moderna||5-month followup, severe disease||USA, high-risk individuals||98.2%|
|mRNA||hospitalization, 65-79 y/os||Portugal||78%||94%|
|mRNA||hospitalization, over 80 y/o||Portugal||55%||82%|
|mRNA||death, 65-79 y/os||Portugal||77%||96%|
|mRNA||death, over 80 y/os||Portugal||56%||81%|
|AZ||ICU or death||Malaysia||96%|
|Pfizer||infection after 1 month||California||88%|
|Pfizer||infection after 5 months||California||47%|
|Pfizer||infection after 16 weeks||North Carolina||81%||91%|
|Novavax||symptomatic infection||USA / Mexico||90.4%|
|Novavax||hospitalization / ICU / death||USA / Mexico||100%|
|AZ||death, 40-60 y/o||Scotland||88%|
|Pfizer||death, 40-60 y/o||Scotland||95%|
|AZ||death, over 60 y/o||Scotland||90%|
|Pfizer||death, over 60 y/o||Scotland||87%|
|AZ||death, all ages||Scotland||90%|
|Pfizer||death, all ages||Scotland||91%|
|Pfizer||infection, 12-17 y/o||Israel||66%||90%|
|Pfizer||symptomatic infection, 12-17 y/o||Israel||82%||93%|
|Moderna||infection, male prisoners||California||56.6%|
|Moderna||symptomatic infection, male prisoners||California||84.2%|
|mRNA||infection given 3-4 week dose interval||British Columbia||85%|
|mRNA||infection given 3-4 week dose interval||Quebec||79%|
|mRNA||infection given 7-8 week dose interval||British Columbia||91%|
|mRNA||infection given 7-8 week dose interval||Quebec||89%|
|mRNA||infection given 3-4 week dose interval||British Columbia and Quebec||93%|
|mRNA||infection given 7-8 week dose interval||British Columbia and Quebec||99%|
|Covaxin||symptomatic infection, hospital staff, from Delta||India||50%|
|Soberana 02||symptomatic infection||Cuba||71%|
|Soberana 02||severe disease||Cuba||63%|
|Soberana 02 with Soberana Plus||symptomatic infection||Cuba||92.4%|
|Soberana 02 with Soberana Plus||severe disease||Cuba||100%|
|Soberana 02 with Soberana Plus||death||Cuba||100%|
|mRNA||infection of military veterans||USA||69%|
|mRNA||death of military veterans||USA||86%|
|Pfizer||hospitalization for 12-18 y/os||USA (23 states)||94%|
|Pfizer||ICU for 12-18 y/os||USA (23 states)||98%|
|Pfizer||death for 12-18 y/os||USA (23 states)||100%|
 In Malaysia, AZ is mostly given to younger people, which potentially makes it look better than it is.
- Pfizer in Israel: M is 14 to 20 days; N is >=7 days
- Pfizer infection2 in Israel: N is > 14 days
- Pfizer in Israel health care workers: N is 15-24 days
- Pfizer, AZ in Scotland: M is 28 to 34 days
- Pfizer in UK health care workers N is 21 days, M is 7 days
- mRNAs in USA: M is >10 days, N is >0 days
- Pfizer transmissibility in Israel: M is >12 days
- Pfizer symptoms3 in Israel: N is >14 days
- Novavax SA: N is not applicable, M is?
- Novavax UK: N is not applicable, M is?
- Sinopharm in Bahrain, UAE, Egypt, Jordan: M is 21 days; N is unclear
- Sinopharm in Bahrain: M is 21 days, N is 14 days. NB: small study!
- Sinovac in Turkey,Indonesia, Brazil: M 14 days, N is >=14 days
- Sinovac in Chile: M is either 14 or 28 days, N is 14 days
- Pfizer and AZ in South Korea: M not applicable; testing 14 days after first shot.
- Pfizer and AZ in UK for 70+ and 80+: M=28 days, N=14 days.
- J&J in the US: M=14 days, N is not applicable
- Sao Paolo against infection: M is 2-4 weeks
- England/B117: M is 7 days, N is 21 days
- Ontario: M is 14 to 41 days, with efficacy increasing with time, N is 7 days.
- Sputnik V in Argentina: M is not applicable, N is 21 to 40 days
- The mRNA study of health care workers by the US CDC didn’t specify M or N.
- South African J&J against severe illness: M is >=28 days, N is not applicable.
- Over-80s with one dose of AZ or Pfizer in the UK: M is >10 days, N is not applicable.
- CoronaVac study in Chile: N>=14 days, M>= 14 days.
- UK study broken out by brand, age, immunosuppressed: N between 28 and 90 days; M>= 14 days.
- US study on immunosuppressive: M>=14 days
- Israel/Pfizer study on pregnant women: There were two different results reported, one for N=14 to 20 and one for N=21 to 27, M=7 to 56 days
- US Department of Veteran’s Affairs study, 15 Dec 2020 to 4 March 2021: N>0 days, M>7 days
- Alberta data: N>14 days, M>14 days
- The Pfizer six-month study: N>11 days. There were two different Ms, one 7 days to two months, and one two to four months.
- Household contacts in Netherlands: N>14 days, M>7 days.
- USA mRNA/J&J study: N>14 days
- Southern California Moderna study: N>=14 days; dosing interval >= 24 days
- Malaysia AZ/Pfizer/Sinovac deaths study: N, M unknown
- Johnson & Johnson, USA, N, M varied.
- Johnson & Johnson two-dose study, M>=14 days, second dose 56 days after first
- Brazilian MMR study, N, M unknown, 8 week dosing interval
- US Pfizer/Moderna health care workers study, M>=14 days through 6 days after second dose, N>=7 days, through May 2021
- Clover Biopharmeceuticals in five countries, N>=14 days, 28 April 2021 through 10 Aug 2021, doses 21 days apart.
- Moderna 5-month followup in US, M>=14 days, ending 26 March 2021
- Portuguese study in old folks, M>=14 days, N>=14, Feb through Aug 2021
- Malaysian multi-vax study, M>=14 days, published 23 Sept 2021.
- North Carolina Pfizer study, submitted 6 Oct 2021.
- Novavax study in USA/Mexico, 3 weeks between dose1 and dose2, N>=7 days, M>xxx, preprint submitted 10 Oct 2021.
- Scotland study of AZ and Pfizer for under/over 60 y/o, N>=14 days, study period April 1 to August 16, 2021 (mostly Delta variant).
- Adolescents in Israel, M=21 to 27 days; N>=7 days, study from June 8 to September 14, 2021.
- Male prisoners in California, M>=14 days, study from July 16 to August 15, 2021.
- Covaxin against infection, severe disease, N>14 days, study from Nov 16, 2020, and Jan 7, 2021.
- Covaxin against Delta infection for hospital staff, N>14 days, study from April 15 and May 15, 2021.
- Soberano 02 and Soberano 02 with Soberano Plus, Soberano Plus given 28 days after the two-dose Soberano series, N>14 days, study from March 8 to March 31, 2021.
- mRNA in US military veterans, N>7 days, study from 11 December 2020 to 25 March 2021.
- Pfizer in US teens, N>14 days, study from July 1 and October 25, 2021.
This article compares Moderna and Pfizer, though TBH I think they are close enough to not worry about.
Non-Coronavirus Vaccines against COVID
There have been a bunch of studies on how well non-coronavirus vaccines are against COVID. Surprisingly, many give some protection. See my page on that.
See above caveats about doing comparisons between vaccines (after fully dosed unless otherwise specified).
|Brand||Where||Against||vs. Classic||vs. Alpha / B.1.1.7||vs. Beta / B.1.351||vs Gamma / P.1||vs. Delta / B.1.617.2|
|Pfizer||Qatar||infection 1 dose||x||29.5%||16.9%||x|
|Pfizer||Qatar||hospitalization 1 dose||x||54.1%||0.0%|
|AZ||UK / Brazil / South Africa||symptomatic?||82%||74.9%||22%||unknown|
|Novavax||UK / South Africa||symptomatic?||95.6% or 89.3%||85.6%||60%||unknown|
|J&J (Janssen)||US / Latin America / South Africa||symptomatic?||72% ||unknown||57%||unknown|
|Sinovac||Brazil / Turkey / Indonesia / Chile||symptomatic?||83.7%? |
|AZ||UK||symptomatic 1 dose||51%||33%|
|AZ||UK||symptomatic 2 doses||66%||60%|
|Pfizer||UK||symptomatic 1 dose||49%||33%|
|Pfizer||UK||symptomatic 2 doses||93%||88%|
|Pfizer||UK||hospitalization 1 dose||83%||94%|
|Pfizer||UK||hospitalization 2 doses||95%||96%|
|AZ||UK||hospitalization 1 dose||76%||71%|
|AZ||UK||hospitalization 2 doses||86%||92%|
|Novavax||South Africa||infection, HIV+||49%|
|Novavax||South Africa||infection, HIV-||55%|
|Moderna||Ontario||infection 1 dose||54%||83%||77%||see Beta ||72%|
|Pfizer||Ontario||infection 1 dose||61%||66%||60%||see Beta|
|AZ||Ontario||infection 1 dose||67%||64%||48%||see Beta|
|Moderna||Ontario||infection 2 doses||89%||92%||x||see Beta|
|Pfizer||Ontario||infection 2 doses||93%||89%||84%||see Beta|
|Moderna||Ontario||hospitalization or death 1 dose||57%||79%||x||see Beta|
|Pfizer||Ontario||hospitalization or death 1 dose||68%||80%||77%||see Beta|
|AZ||Ontario||hospitalization or death 1 dose||x||85%||83%||see Beta|
|Moderna||Ontario||hospitalization or death 2 doses||96%||94%||x||x||x|
|Pfizer||Ontario||hospitalization or death 2 doses||96%||95%||95%||see Beta|
|Moderna||Qatar||infection 1 dose||88.1%||61.3%|
|Moderna||Qatar||infection 2 doses||100%||96.4%|
|AZ||England||infection 1 dose||48.7%||30.7%|
|AZ||England||infection 2 doses||74.5%||67.0%|
|Pfizer||England||infection 1 dose||47.5%||35.6%|
|Pfizer||England||infection 2 doses||93.7%||88.0%|
|AZ or AZ+mRNA||Denmark||asymptomatic infection||95.9%||88.1%|
|AZ or AZ+mRNA||Denmark||hospitalization||N/A||96.6%|
|Johnson & Johnson||USA||infection||78%|
|Johnson & Johnson||USA||hospitalization||85%|
|Clover||Philippines, Colombia, South Africa, Brazil, Belgium||infection||91.8%||78.7%|
|Clover||Philippines, Colombia, South Africa, Brazil, Belgium||hospitalization||100%||100%|
“or” means that different sources reported different things
 US study. 66% in Latin America (Brazil, Colombia, Peru, Chile, Argentina, Mexico)
 Trial was in Brazil, but unknown how much P.1 was in the sample.
 From the counts of who was hospitalized and who wasn’t, this didn’t look to me like it should be 0%, but I couldn’t completely understand the data.
 For the Ontario multi-VOC study, they grouped Beta and Gamma together.
 For the Johnson & Johnson study, this data was from June/July 2021 in US states where Delta was predominant.
Efficacy against Omicron
(The chart above was getting too wide and crowded.)
|Pfizer or AZ||England||hospitalization||omicron wave||2 or 3||81%|
|Pfizer or AZ||England||hospitalization||omicron wave||3||88%|
|J&J||South Africa||hospitalization after 0-13 days||2021-Nov-15 to 2021-Dec-20||2||63%|
|J&J||South Africa||hospitalization after 14-27 days||2021-Nov-15 to 2021-Dec-20||2||84%|
|J&J||South Africa||hospitalization after 1-2 months||2021-Nov-15 to 2021-Dec-20||2||85%|
|Moderna||California||infection at 14-90 days||2021-12-06 to 2021-12-23||2||30.4%|
|Moderna||California||infection||2021-12-06 to 2021-12-23||3||62.5%|
|Pfizer||California||Emergency Department admission, <3 months post vax||Dec 01, 2021 through Jan 11, 2022||2||60%|
|Pfizer||California||Emergency Department admission, over 3 months post vax||Dec 01, 2021 through Jan 11, 2022||2||41%|
|Pfizer||California||Emergency Department admission, <3 months post vax||Dec 01, 2021 through Jan 11, 2022||3||78%|
|Pfizer||California||Emergency Department admission, over 3 months post vax||Dec 01, 2021 through Jan 11, 2022||3||48%|
|Pfizer||California||hospital admission||Dec 01, 2021 through Jan 11, 2022||2||68%|
|Pfizer||California||hospital admission||Dec 01, 2021 through Jan 11, 2022||2||89%|
What is the optimal interval?
It is my understanding that in most vaccines, you want a fairly long interval between dose 1 and dose 2. The immune system needs some time to learn and train from the first dose.
Why then, are were the recommended intervals so short initially? Because the vaccine makers were in a real hurry. They did the absolute shortest interval that they thought they could get away with.
There have been a lot of people who have had longer intervals since then. It was a bit of a calculated gamble to do so before the data was in, but it was apparently a pretty safe bet, since all other vaccines did better with a longer dose interval.
Since then, there have been a few studies.
- This study of Pfizer in people over 80 found that they generated 2.5x as many antibodies with a 12-week interval than with a 4-week interval.
- This study of AZ found that antibodies were higher with a 12-week dose interval than an interval shorter than six weeks.
- This study of AZ found that antibodies were higher the longer the dosing interval was. They studied up to 44 weeks.
- This study of Pfizer found that neutralizing antibodies were higher for a long dosing interval (6-14 weeks) compared to a short interval (3-4 weeks).
- This study of Pfizer found that a 16-week interval was better than a 4 week interval.
- This study of Pfizer and Moderna found that antibody levels were higher in people who had a 6 to 7 week interval than in people who had a 3 to 4 week interval.
There also have been literally millions of people who have had a longer interval. For example, in BC, most of the 2.3M people who have gotten a second dose (as of 18 July 2021) have had a dose interval longer than 7 weeks. (Mine was ten weeks; my partner’s eleven.) The UK has also had a long dose interval.
There have been a bunch of studies documenting a significant decrease in effectiveness against infection over time. There is a small drop against hospitalization and death, but not nearly as large.
It is not entirely surprising that the vaccines are less effective against infection but still very good against severe disease. Antibodies are the first line of defence, and they are kind of designed to go away when they are not needed, but to get called back in force when there is an infection. It takes a few days for a new antibody army to get raised, however, which gives time for infection to take hold.
The first Pfizer clinical trials said that the vaccine efficacy after only one dose was 92%, but this re-examination of the clinical data gives much better numbers:
I believe I saw another paper which said that the efficacy declined quite a bit after five weeks, but I would have to dig a bit harder to find that the paper.
This preprint did a meta-analysis of a bunch of waning studies. They found that vaccine effectiveness dropped a lot between 1 and 6 months after the second dose:
This study from BC and Quebec showed a lot less waning — more like 10% than 20-30% — for long dose intervals than for short dose intervals:
This preprint reports waning of two doses of AZ in Scotland and Brazil. The vaccine effectiveness against severe disease was:
|2-3 weeks||14-15 weeks||18-19 weeks|
Note that there are lot of papers on waning effectiveness, I just got bored writing them all down.
This publication from Public Health England says that the vaccine effectiveness was 93.1% for those over 50 with AZ+AZ+Pfizer and 94.0% for Pfizer+Pfizer+Pfizer.
This big study which looked at Pfizer, Moderna, AZ, J&J, Novavax, CureVac, and Valneva as boosters for AZ/AZ or Pfizer/Pfizer found that (broadly speaking), the more mRNA, the better. (See my 2 Dec 2021 analysis for more detail and nuance.)
<there have been a bunch more booster studies, they all show that a booster increases effectiveness against infection, at least in the short term… I need to add them in…>
This preprint says that the J&J boosters (i.e. second dose) in South Africa does well. Its effectiveness against infection was:
- 63% effective 0-13 days after the second dose
- 84% effective 14-27 days days after the second dose
- 85% effective 1-2 months days after the second dose