COVID-19: first direct comparison of Pfizer and Moderna vaccines from real vaccination data

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In the first head-to-head comparison of the effectiveness of the Pfizer-BioNTech and Moderna COVID-19 vaccines, researchers examined the electronic health records of veterans who had received each vaccine.

Both vaccines were highly effective in preventing COVID-19 outcomes such as documented infection, hospitalization, and death.

However, the Moderna vaccine was found to offer an increased level of protection, including a 21% lower risk of documented infection and 41% lower risk of hospitalization, according to the research team, whose findings were published on December 1, 2021, in the New England Journal of Medicine.

“Both vaccines are incredibly effective, with only rare breakthrough cases,” said Dr. J.P. Casas, a member of the research team made up of experts from the U.S. Department of Veterans Affairs (VA), the Harvard T.H. Chan School of Public Health, and Brigham and Women’s Hospital.

“But regardless of the predominant strain – Alpha earlier and then Delta later – Moderna was shown to be slightly more effective,” said Casas, an epidemiologist and associate professor with Brigham and Women’s Hospital and Harvard Medical School and executive director of the VA’s Million Veteran Program for genetics and health research.

Researchers designed their comparative effectiveness study to address the previously unanswered question of which of the two mRNA vaccines is more effective.

Effectiveness was measured in terms of five COVID-related outcomes: documented COVID-19, symptomatic disease, hospitalization, ICU admission, and death.

The investigators relied on the electronic health records of U.S. veterans who received one of the two COVID-19 vaccines between early January 2021 and mid-May 2021.

As initially designed, the research focused on the Alpha variant that predominated at the time. The study matched 219,842 recipients of the Pfizer vaccine to the same number of recipients of the Moderna vaccine. The two groups were matched based on a variety of clinical and demographic factors that could affect outcomes.

Over the study’s 24-week follow-up period, the estimated risk of documented infection was 4.52 events per 1,000 people in the Moderna vaccine group and 5.75 per 1,000 in the Pfizer group. This represents an excess of 1.23 cases of documented infection per 1,000 people in the Pfizer group.

The investigators also observed an excess of symptomatic COVID-19 (0.44 events), hospitalization (0.55 events), ICU admission (0.10 events), and death (0.02 events) per 1,000 people in the Pfizer group relative to the Moderna group, but these differences were smaller.

This pattern of a lower risk for Moderna held up in an additional phase of research covering a time frame with Delta as the main strain. In this comparison, excess risk of documented infection over 12 weeks was 6.54 events per 1,000 people for the Pfizer vaccine, compared to Moderna.

Given the shorter time frame available for this supplementary research, infection was the only outcome researchers analyzed. Also, the estimates were considered less precise because a smaller number of individuals were eligible for this analysis.

Randomized trials comparing the mRNA vaccines against placebos had previously shown both vaccines to be very effective against symptomatic COVID-19 infection (95% effectiveness for Pfizer-BioNTech, 94% for Moderna), and similar benefits were observed in real-world vaccine use.

“Given the high effectiveness of both the Moderna and Pfizer vaccines, confirmed by our study, either one is recommended to any individual offered a choice between the two,” said the study’s first author, Dr. Barbra A. Dickerman, an epidemiology instructor with the Harvard T.H. Chan School of Public Health.

“However, while the estimated differences in effectiveness were small on an absolute scale, they may be meaningful when considering the large population scale at which these vaccines are deployed. This information may be helpful for larger decision-making bodies.”

The expansive VA records system, covering millions of patients nationwide, supported a very large sample size. This, in turn, allowed the study to identify even small differences in effectiveness between the Pfizer and Moderna vaccines. The researchers used a methodology known as causal inference to mirror a randomized trial – the gold standard in health research – as closely as possible. Causal inference is type of data analysis that helps researchers draw firm conclusions about cause and effect.

Causal inference experts on the research team included Dickerman and Dr. Miguel A. Hernán, a Harvard School of Public Health professor of biostatistics and epidemiology and director of the school’s CAUSALab. Dickerman, Hernán, and Casas co-direct the Methods Core of VA-CAUSAL, a VA-Harvard partnership focusing on the development of new methods for causal inference in research.

A primary challenge for this research was ensuring that the vaccine groups under study were comparable with respect to attributes, other than the vaccine received, that may predict infection or disease severity.

The VA databases allowed the researchers to precisely characterize recipients of each vaccine type and closely match them on age, sex, race, geographic location, and other attributes that could affect COVID-19-related outcomes.

“After this careful matching, we found that the two vaccine groups were extremely similar in terms of variables with respect to an extensive set of demographic, geographic, and health-related attributes,” Dickerman said. “This allowed our observational analysis to produce exceptionally credible results during a global emergency, when answers are needed fast and randomized trials can be impractical.”

As the global pandemic continues to unfold, the research team is working on answers relating to the comparative safety, versus effectiveness, of the Pfizer and Moderna vaccines. Dickerman characterizes comparative safety as an “additional piece of the puzzle to support vaccine decision-making.”

Even beyond this analysis, further evaluation of the vaccines’ comparative effectiveness and safety is needed, the authors concluded in their New England of Journal of Medicine article. Meanwhile, given the evidence already gathered, the authors concluded about the Pfizer and Moderna vaccines considered in their study, “Given the high effectiveness and safety profile of both mRNA vaccines, either one is strongly recommended.”


. . . . . AND … reference source : https://www.harvardmagazine.com/2021/12/moderna-more-effective

Other researchers have previously documented a higher antibody response among recipients of the Moderna vaccine, and speculated about the cause, including differences in the dose of mRNA, timing of the first and second shots (Moderna’s four-week versus Pfizer’s three-week interval) and the composition of the lipid nanoparticles used to deliver the vaccines.

But “there has been a need for studies that compare the vaccines head-to-head,” write the authors, that “are large enough to provide precise risk estimates for severe COVID-19 outcomes,” that “include racially diverse groups,” are carefully designed, and that address efficacy against different variants of the SARS-CoV-2 virus. 

The differences in infection rates for the two vaccinated groups were very small: the researchers estimate that there were 5.75 infections per 1,000 persons for the Pfizer vaccine group and 4.52 infections per 1,000 persons for the Moderna vaccine group during the period when the Alpha variant was dominant—a little more than one excess infection per 1,000 people. After Delta became the dominant strain, the researchers found an additional 6.54 infections per 1,000 persons in the Pfizer group. 

Because both vaccines are highly effective, breakthrough cases are rare, and “either one is strongly recommended to any individual offered the choice between the two,” said first author Barbra Dickerman, a CAUSALab investigator and instructor in the department of epidemiology at HSPH.

On the other hand, while the differences in estimated risk are small in an absolute sense, Dickerman adds, “they may be meaningful for larger decision-making bodies,” such as healthcare systems and governments, “when considering the large population scale at which these vaccines are deployed.”

The current study did not address the comparative safety of the two vaccines, another important consideration at both the individual and population level. “This is something we are actively investigating,” said Dickerman (whose work  on a HarvardX course about causality in public health, together with senior author and Kolokotrones professor of biostatistics and epidemiology Miguel Hernan was described in the 2017 Harvard Magazine article, “Making a MOOC.”)

NOR DOES IT SHED LIGHT on the potential efficacy of either vaccine against the new variant, Omicron, the first U.S. case of which was reported in California today. But scientists who study the virus and its vulnerabilities to known antibodies, are very concerned. 

Leaders of the Massachusetts Consortium for Pathogen Readiness (MCPR) addressed the many unknowns around Omicron, including its origins, transmissibility, and its ability to evade existing vaccines and treatments, in a news conference held this afternoon.

Jeremy Luban, a professor in the program in molecular medicine at the University of Massachusetts Medical School who co-leads MCPR’s viral variants research program, said that during the course of the pandemic, vaccine researchers, including those responsible for developing the Pfizer, Moderna, and Johnson & Johnson vaccines, have been screening blood samples from vaccinated individuals for antibody reactivity against each of the new variants as they have appeared.

“One of the most scary things about Omicron,” Luban said, “is how many mutations it has in critical sites that are known to be targeted by antibodies.”

While Delta has seven mutations in the spike, Omicron has more than 30, many of which have never been seen in patients before, but have been anticipated by scientists who have observed such mutations in the presence of antibodies during lab testing. In the scientific community, he said, “everyone is pivoting to anticipate that changes will be needed in the vaccines.”

It is possible that high levels of antibodies induced by the recent boosters will help even against the mutations in the spike protein that the virus uses to enter cells. And deep immune responses that rely on T-cells may also hold up, the researchers said. 

But some of the COVID-19 treatments that have recently been developed, such as the monoclonal antibody cocktail from Regeneron, are reportedly less likely to be effective. Others that don’t target the spike protein directly, it is hoped, may continue to work.

Jacob Lemieux, an HMS instructor in medicine and infectious disease , and a physician investigator at Massachusetts General Hospital, noted that outbreaks like the one in South Africa that brought Omicron to the attention of the world can be driven by factors other than increased transmissibility of the viral variant, such as a superspreader event.

But during the last few days, he said, the “alarmingly escalating epidemic” there, with a test positivity rate of 16 percent, increases the likelihood that Omicron will spread widely during the next few weeks and months. 

Nahid Bhadelia, an associate professor of infectious disease, director of the center for emerging infectious diseases at Boston University Medical Center, and faculty co-leader of MCPR’s long-COVID program, said that one of the most important questions about the new variant—whether it causes more severe disease—won’t be known for at least a few more weeks. But she also had some potentially reassuring news: the antivirals currently being tested don’t achieve their effectiveness by attacking the spike protein, which is where Omicron’s changes lie. So “you are less likely to see an impact on them in the clinical space,” she said, “once they are approved.”

How Omicron accumulated so many new mutations is unknown, but speculation ranges from evolution in an immunocompromised individual, to a jump from humans into an animal host, and then back again, in a sort of “reverse zoonosis.” One thing is certain, emphasized Ragon professor of medicine Bruce Walker, one of the leaders of MCPR: this virus is not going away.

 “We all hoped we’d be in a different place right now,” concluded Lemieux. But with respect to the path ahead, he said, “there are things we can do. Get vaccinated. Modify the vaccines. And modify monoclonal antibody treatments.” 

Coronavirus (COVID-19) Vaccinations

54.5% of the world population has received at least one dose of a COVID-19 vaccine.
8.03 billion doses have been administered globally, and 32.61 million are now administered each day.
Only 6% of people in low-income countries have received at least one dose.

Total vaccinations (per 100)
Dec 1, 2020Dec 1, 2021Absolute ChangeRelative Change
AfghanistanFeb 22, 2021 0.00Nov 20, 2021 12.84+12.84
AfricaJan 9, 2021 0.0017.61+17.61
AlbaniaJan 10, 2021 0.00Nov 30, 2021 73.13+73.13
AlgeriaJan 29, 2021 0.00Nov 26, 2021 27.07+27.07
AndorraJan 25, 2021 0.74Oct 31, 2021 135.14+134.40+18,162%
AngolaMar 1, 2021 0.00Nov 24, 2021 26.60+26.60
AnguillaFeb 4, 2021 0.00131.66+131.66
Antigua and BarbudaFeb 16, 2021 0.00Nov 26, 2021 119.15+119.15
ArgentinaDec 29, 2020 0.00151.02+151.02
ArmeniaMar 31, 2021 0.02Nov 28, 2021 41.02+41.00+205,000%
ArubaMar 29, 2021 24.04150.80+126.76+527%
AsiaDec 15, 2020 0.03117.01+116.98+389,933%
AustraliaFeb 21, 2021 0.00152.69+152.69
AustriaDec 27, 2020 0.01155.54+155.53+1,555,300%
AzerbaijanJan 17, 2021 0.00103.37+103.37
BahamasMar 13, 2021 0.00Nov 29, 2021 70.59+70.59
BahrainDec 23, 2020 2.23167.95+165.72+7,431%
BangladeshJan 26, 2021 0.0059.27+59.27
BarbadosFeb 15, 2021 1.56Nov 30, 2021 100.92+99.36+6,369%
BelarusDec 28, 2020 0.00Nov 21, 2021 63.28+63.28
BelgiumDec 28, 2020 0.00147.19+147.19
BelizeFeb 28, 2021 0.00Nov 29, 2021 100.70+100.70
BeninMay 12, 2021 0.09Nov 19, 2021 3.08+2.99+3,322%
BermudaJan 10, 2021 0.00Nov 5, 2021 163.21+163.21
BhutanMar 26, 2021 0.00Nov 21, 2021 147.88+147.88
BoliviaJan 28, 2021 0.00Nov 11, 2021 67.96+67.96
Bonaire Sint Eustatius and SabaApr 9, 2021 27.95Sep 1, 2021 135.55+107.60+385%
Bosnia and HerzegovinaFeb 11, 2021 0.00Nov 4, 2021 47.61+47.61
BotswanaMar 25, 2021 0.00Nov 24, 2021 56.42+56.42
BrazilJan 17, 2021 0.00145.22+145.22
British Virgin IslandsMay 21, 2021 49.41Nov 29, 2021 114.75+65.34+132%
BruneiApr 2, 2021 0.00170.42+170.42
BulgariaDec 29, 2020 0.0248.57+48.55+242,750%
Burkina FasoJun 2, 2021 0.00Nov 4, 2021 3.08+3.08
BurundiOct 19, 2021 0.00Nov 26, 2021 0.01+0.01
CambodiaFeb 9, 2021 0.00169.80+169.80
CameroonApr 11, 2021 0.00Nov 29, 2021 3.50+3.50
CanadaDec 14, 2020 0.00159.66+159.66
Cape VerdeMar 18, 2021 0.00Nov 26, 2021 96.83+96.83
Cayman IslandsDec 26, 2020 0.00Nov 29, 2021 186.29+186.29
Central African RepublicMay 12, 2021 0.01Nov 19, 2021 8.59+8.58+85,800%
ChadJun 10, 2021 0.03Nov 27, 2021 1.53+1.50+5,000%
ChileDec 24, 2020 0.00Nov 30, 2021 213.38+213.38
ChinaDec 15, 2020 0.10174.24+174.14+174,140%
ColombiaFeb 17, 2021 0.00Nov 29, 2021 111.36+111.36
ComorosApr 21, 2021 1.51Nov 28, 2021 58.89+57.38+3,800%
CongoApr 14, 2021 0.25Nov 24, 2021 11.06+10.81+4,324%
Cook IslandsMay 25, 2021 24.83Nov 8, 2021 138.44+113.61+458%
Costa RicaDec 24, 2020 0.00Nov 29, 2021 138.90+138.90
Cote d’IvoireMar 1, 2021 0.00Nov 14, 2021 14.22+14.22
CroatiaDec 30, 2020 0.19Nov 30, 2021 101.77+101.58+53,463%
CubaMay 31, 2021 18.01Nov 29, 2021 251.24+233.23+1,295%
CuracaoMar 29, 2021 11.90120.26+108.36+911%
CyprusJan 6, 2021 0.44Nov 27, 2021 146.29+145.85+33,148%
CzechiaDec 27, 2020 0.01126.80+126.79+1,267,900%
Democratic Republic of CongoApr 18, 2021 0.00Nov 29, 2021 0.21+0.21
DenmarkFeb 10, 2021 5.86Nov 30, 2021 169.09+163.23+2,785%
DjiboutiApr 17, 2021 1.02Nov 24, 2021 9.95+8.93+875%
DominicaFeb 11, 2021 0.00Nov 29, 2021 76.93+76.93
Dominican RepublicFeb 15, 2021 0.00Nov 30, 2021 126.14+126.14
EcuadorJan 20, 2021 0.00Nov 29, 2021 137.87+137.87
EgyptJan 24, 2021 0.00Nov 28, 2021 38.28+38.28
El SalvadorFeb 17, 2021 0.00Nov 30, 2021 140.83+140.83
Equatorial GuineaMar 16, 2021 0.45Nov 29, 2021 30.74+30.29+6,731%
EstoniaDec 27, 2020 0.01111.87+111.86+1,118,600%
EswatiniMar 30, 2021 0.00Nov 24, 2021 26.14+26.14
EthiopiaApr 8, 2021 0.368.11+7.75+2,153%
Europe0.00127.77+127.77
European Union0.00143.87+143.87
Faeroe IslandsJan 29, 2021 8.14Nov 5, 2021 159.72+151.58+1,862%
Falkland IslandsFeb 7, 2021 0.00Apr 14, 2021 124.91+124.91
FijiMar 17, 2021 0.00Nov 30, 2021 137.02+137.02
FinlandDec 31, 2020 0.03149.97+149.94+499,800%
FranceDec 27, 2020 0.00Nov 30, 2021 156.65+156.65
French PolynesiaFeb 2, 2021 0.75Nov 30, 2021 112.83+112.08+14,944%
GabonMar 22, 2021 0.00Nov 24, 2021 12.20+12.20
GambiaMar 9, 2021 0.00Nov 21, 2021 10.78+10.78
GeorgiaMar 14, 2021 0.0055.23+55.23
GermanyDec 27, 2020 0.03148.27+148.24+494,133%
GhanaMar 1, 2021 0.00Nov 24, 2021 11.01+11.01
GibraltarJan 10, 2021 1.25292.13+290.88+23,270%
GreeceDec 28, 2020 0.00138.92+138.92
GreenlandJan 27, 2021 4.54Nov 25, 2021 136.55+132.01+2,908%
GrenadaFeb 11, 2021 0.00Nov 29, 2021 66.10+66.10
GuatemalaFeb 25, 2021 0.00Nov 30, 2021 55.18+55.18
GuernseyJan 24, 2021 10.53Nov 22, 2021 164.28+153.75+1,460%
GuineaMar 31, 2021 0.46Nov 28, 2021 18.22+17.76+3,861%
Guinea-BissauMay 12, 2021 0.29Nov 28, 2021 18.28+17.99+6,203%
GuyanaFeb 11, 2021 0.0086.18+86.18
HaitiJul 16, 2021 0.00Nov 19, 2021 1.60+1.60
High income0.00150.35+150.35
HondurasFeb 28, 2021 0.03Nov 29, 2021 79.11+79.08+263,600%
Hong KongFeb 22, 2021 0.00125.30+125.30
HungaryDec 28, 2020 0.01Nov 29, 2021 148.25+148.24+1,482,400%
IcelandDec 30, 2020 1.42Nov 30, 2021 188.90+187.48+13,203%
IndiaJan 15, 2021 0.0089.39+89.39
IndonesiaJan 12, 2021 0.0085.66+85.66
IranFeb 8, 2021 0.00Nov 27, 2021 123.03+123.03
IraqMar 1, 2021 0.00Nov 28, 2021 29.26+29.26
IrelandDec 28, 2020 0.00166.59+166.59
Isle of ManJan 21, 2021 4.17155.90+151.73+3,639%
IsraelDec 19, 2020 0.00174.47+174.47
ItalyDec 27, 2020 0.01160.60+160.59+1,605,900%
JamaicaMar 9, 2021 0.0037.48+37.48
JapanFeb 17, 2021 0.00Nov 30, 2021 156.50+156.50
JerseyMar 14, 2021 45.27Nov 24, 2021 182.93+137.66+304%
JordanJan 12, 2021 0.0076.90+76.90
KazakhstanJan 31, 2021 0.0088.70+88.70
KenyaMar 4, 2021 0.00Nov 30, 2021 13.05+13.05
KiribatiJun 1, 2021 0.00Nov 30, 2021 67.69+67.69
KosovoMar 28, 2021 0.0090.76+90.76
KuwaitDec 28, 2020 0.06Nov 30, 2021 151.98+151.92+253,200%
KyrgyzstanMar 28, 2021 0.0030.68+30.68
LaosMar 17, 2021 0.55Nov 23, 2021 79.00+78.45+14,264%
LatviaDec 4, 2020 0.00118.07+118.07
LebanonFeb 13, 2021 0.0053.31+53.31
LesothoMar 9, 2021 0.00Nov 17, 2021 28.61+28.61
LiberiaMay 12, 2021 0.70Nov 18, 2021 11.38+10.68+1,526%
LibyaApr 17, 2021 0.01Nov 28, 2021 33.57+33.56+335,600%
LiechtensteinDec 21, 2020 0.00Nov 30, 2021 133.63+133.63
LithuaniaDec 27, 2020 0.09138.33+138.24+153,600%
Low incomeFeb 15, 2021 0.008.28+8.28
Lower middle incomeJan 12, 2021 0.0072.00+72.00
LuxembourgDec 28, 2020 0.07Nov 28, 2021 144.52+144.45+206,357%
MacaoFeb 8, 2021 0.00Nov 30, 2021 139.58+139.58
MadagascarMay 12, 2021 0.00Nov 29, 2021 2.41+2.41
MalawiMar 17, 2021 0.037.29+7.26+24,200%
MalaysiaFeb 24, 2021 0.00Nov 30, 2021 163.04+163.04
MaldivesFeb 2, 2021 0.16Nov 30, 2021 142.02+141.86+88,663%
MaliMar 30, 2021 0.00Nov 28, 2021 4.06+4.06
MaltaJan 17, 2021 2.27Nov 30, 2021 185.99+183.72+8,093%
MauritaniaMar 26, 2021 0.00Nov 24, 2021 36.31+36.31
MauritiusJan 25, 2021 0.00Nov 23, 2021 147.25+147.25
MexicoDec 24, 2020 0.00101.98+101.98
MoldovaMar 5, 2021 0.10Nov 30, 2021 40.39+40.29+40,290%
MonacoDec 30, 2020 0.00Sep 16, 2021 126.47+126.47
MongoliaFeb 22, 2021 0.00132.54+132.54
MontenegroFeb 20, 2021 0.0084.65+84.65
MontserratFeb 8, 2021 0.00Nov 12, 2021 59.20+59.20
MoroccoJan 28, 2021 0.00Nov 28, 2021 130.63+130.63
MozambiqueMar 7, 2021 0.00Nov 29, 2021 31.55+31.55
MyanmarJan 26, 2021 0.00Nov 20, 2021 47.20+47.20
NamibiaMar 18, 2021 0.00Nov 24, 2021 25.12+25.12
NauruApr 8, 2021 0.00Aug 31, 2021 136.70+136.70
NepalJan 26, 2021 0.00Nov 22, 2021 57.95+57.95
NetherlandsJan 6, 2021 0.02Nov 29, 2021 143.46+143.44+717,200%
New CaledoniaFeb 2, 2021 0.39Nov 30, 2021 121.56+121.17+31,069%
New ZealandFeb 18, 2021 0.00Nov 29, 2021 147.14+147.14
NicaraguaMar 1, 2021 0.0095.13+95.13
NigerMar 28, 2021 0.00Nov 28, 2021 3.87+3.87
NigeriaMar 4, 2021 0.00Nov 25, 2021 4.66+4.66
NiueJun 21, 2021 0.00Aug 2, 2021 145.72+145.72
North AmericaDec 13, 2020 0.00125.61+125.61
North MacedoniaFeb 16, 2021 0.00Nov 22, 2021 80.46+80.46
Northern CyprusJan 14, 2021 0.00Nov 26, 2021 161.52+161.52
NorwayDec 2, 2020 0.00Nov 30, 2021 158.61+158.61
OceaniaFeb 2, 2021 0.01116.01+116.00+1,160,000%
OmanDec 28, 2020 0.03Nov 23, 2021 113.62+113.59+378,633%
PakistanFeb 2, 2021 0.0055.09+55.09
PalestineMar 30, 2021 1.57Nov 22, 2021 57.91+56.34+3,589%
PanamaJan 20, 2021 0.01128.27+128.26+1,282,600%
Papua New GuineaMar 30, 2021 0.00Nov 30, 2021 5.12+5.12
ParaguayFeb 22, 2021 0.00Nov 29, 2021 83.94+83.94
PeruFeb 8, 2021 0.00Nov 30, 2021 125.43+125.43
PhilippinesFeb 28, 2021 0.0080.21+80.21
PitcairnJun 15, 2021 100.00Sep 7, 2021 200.00+100.00+100%
PolandDec 28, 2020 0.01111.21+111.20+1,112,000%
PortugalDec 27, 2020 0.05Nov 15, 2021 160.39+160.34+320,680%
QatarDec 22, 2020 0.00170.26+170.26
RomaniaDec 27, 2020 0.01Nov 30, 2021 78.04+78.03+780,300%
RussiaDec 15, 2020 0.0287.41+87.39+436,950%
RwandaFeb 15, 2021 0.00Nov 24, 2021 65.89+65.89
Saint HelenaFeb 3, 2021 1.76May 5, 2021 129.48+127.72+7,257%
Saint Kitts and NevisFeb 22, 2021 0.00Nov 29, 2021 97.83+97.83
Saint LuciaFeb 16, 2021 0.0054.80+54.80
Saint Vincent and the GrenadinesMar 17, 2021 8.05Nov 27, 2021 48.95+40.90+508%
SamoaMay 4, 2021 3.70Nov 30, 2021 124.28+120.58+3,259%
San MarinoFeb 27, 2021 0.10Nov 21, 2021 140.58+140.48+140,480%
Sao Tome and PrincipeMar 15, 2021 0.00Nov 26, 2021 54.33+54.33
Saudi ArabiaJan 6, 2021 0.39134.26+133.87+34,326%
SenegalFeb 22, 2021 0.00Nov 26, 2021 11.11+11.11
SerbiaJan 8, 2021 0.10Nov 30, 2021 114.96+114.86+114,860%
SeychellesJan 9, 2021 0.00Nov 29, 2021 181.44+181.44
Sierra LeoneMar 14, 2021 0.00Nov 26, 2021 10.67+10.67
SingaporeJan 11, 2021 0.06Nov 5, 2021 184.89+184.83+308,050%
Sint Maarten (Dutch part)May 7, 2021 56.73Nov 29, 2021 119.06+62.33+110%
SlovakiaJan 4, 2021 0.0191.38+91.37+913,700%
SloveniaDec 27, 2020 0.30129.32+129.02+43,007%
Solomon IslandsMar 23, 2021 0.00Nov 30, 2021 29.55+29.55
SomaliaApr 17, 2021 0.72Nov 13, 2021 5.90+5.18+719%
South AfricaFeb 16, 2021 0.0042.94+42.94
South AmericaDec 24, 2020 0.00136.46+136.46
South KoreaFeb 26, 2021 0.06Nov 30, 2021 166.36+166.30+277,167%
South SudanApr 5, 2021 0.00Nov 23, 2021 1.92+1.92
SpainJan 4, 2021 0.18Nov 30, 2021 164.04+163.86+91,033%
Sri LankaJan 28, 2021 0.00138.07+138.07
SudanMar 10, 2021 0.00Oct 20, 2021 3.70+3.70
SurinameFeb 22, 2021 0.0080.58+80.58
SwedenJan 3, 2021 0.02156.44+156.42+782,100%
SwitzerlandDec 21, 2020 0.00Nov 30, 2021 136.71+136.71
SyriaMar 1, 2021 0.00Nov 28, 2021 7.78+7.78
TaiwanMar 21, 2021 0.00133.35+133.35
TajikistanMay 7, 2021 0.71Nov 21, 2021 54.28+53.57+7,545%
TanzaniaAug 8, 2021 0.17Oct 29, 2021 1.63+1.46+859%
ThailandFeb 27, 2021 0.00133.28+133.28
TimorApr 14, 2021 0.20Nov 23, 2021 79.47+79.27+39,635%
TogoMar 9, 2021 0.00Nov 26, 2021 19.64+19.64
TokelauJun 21, 2021 0.00Oct 12, 2021 141.52+141.52
TongaApr 20, 2021 2.14Nov 30, 2021 110.70+108.56+5,073%
Trinidad and TobagoFeb 15, 2021 0.0091.99+91.99
TunisiaMar 12, 2021 0.00Nov 30, 2021 88.48+88.48
TurkeyJan 13, 2021 0.00141.71+141.71
TurkmenistanFeb 28, 2021 0.85Aug 29, 2021 123.91+123.06+14,478%
Turks and Caicos IslandsJan 10, 2021 0.00Nov 5, 2021 143.64+143.64
TuvaluApr 27, 2021 20.13Oct 22, 2021 101.58+81.45+405%
UgandaMar 9, 2021 0.00Nov 15, 2021 10.08+10.08
UkraineFeb 24, 2021 0.0057.41+57.41
United Arab EmiratesJan 5, 2021 8.27Nov 15, 2021 215.68+207.41+2,508%
United KingdomJan 10, 2021 3.93Nov 30, 2021 170.07+166.14+4,227%
United StatesDec 13, 2020 0.01137.45+137.44+1,374,400%
Upper middle incomeDec 15, 2020 0.06150.59+150.53+250,883%
UruguayFeb 27, 2021 0.01195.01+195.00+1,950,000%
UzbekistanMar 31, 2021 0.00Nov 30, 2021 99.22+99.22
VanuatuJun 1, 2021 0.00Nov 22, 2021 41.21+41.21
VenezuelaFeb 17, 2021 0.00Nov 29, 2021 91.67+91.67
VietnamMar 7, 2021 0.00Nov 29, 2021 124.36+124.36
Wallis and FutunaMar 23, 2021 11.59Nov 30, 2021 107.62+96.03+829%
World0.00102.41+102.41
YemenMay 9, 2021 0.06Nov 28, 2021 2.54+2.48+4,133%
ZambiaApr 14, 2021 0.00Nov 29, 2021 5.74+5.74
ZimbabweFeb 18, 2021 0.0044.00+44.00

More information: Barbra A. Dickerman et al, Comparative Effectiveness of BNT162b2 and mRNA-1273 Vaccines in U.S. Veterans, New England Journal of Medicine (2021). DOI: 10.1056/NEJMoa2115463

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