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.
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.
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.
“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, 2020 | Dec 1, 2021 | Absolute Change | Relative Change | |
| Afghanistan | Feb 22, 2021 0.00 | Nov 20, 2021 12.84 | +12.84 | |
| Africa | Jan 9, 2021 0.00 | 17.61 | +17.61 | |
| Albania | Jan 10, 2021 0.00 | Nov 30, 2021 73.13 | +73.13 | |
| Algeria | Jan 29, 2021 0.00 | Nov 26, 2021 27.07 | +27.07 | |
| Andorra | Jan 25, 2021 0.74 | Oct 31, 2021 135.14 | +134.40 | +18,162% |
| Angola | Mar 1, 2021 0.00 | Nov 24, 2021 26.60 | +26.60 | |
| Anguilla | Feb 4, 2021 0.00 | 131.66 | +131.66 | |
| Antigua and Barbuda | Feb 16, 2021 0.00 | Nov 26, 2021 119.15 | +119.15 | |
| Argentina | Dec 29, 2020 0.00 | 151.02 | +151.02 | |
| Armenia | Mar 31, 2021 0.02 | Nov 28, 2021 41.02 | +41.00 | +205,000% |
| Aruba | Mar 29, 2021 24.04 | 150.80 | +126.76 | +527% |
| Asia | Dec 15, 2020 0.03 | 117.01 | +116.98 | +389,933% |
| Australia | Feb 21, 2021 0.00 | 152.69 | +152.69 | |
| Austria | Dec 27, 2020 0.01 | 155.54 | +155.53 | +1,555,300% |
| Azerbaijan | Jan 17, 2021 0.00 | 103.37 | +103.37 | |
| Bahamas | Mar 13, 2021 0.00 | Nov 29, 2021 70.59 | +70.59 | |
| Bahrain | Dec 23, 2020 2.23 | 167.95 | +165.72 | +7,431% |
| Bangladesh | Jan 26, 2021 0.00 | 59.27 | +59.27 | |
| Barbados | Feb 15, 2021 1.56 | Nov 30, 2021 100.92 | +99.36 | +6,369% |
| Belarus | Dec 28, 2020 0.00 | Nov 21, 2021 63.28 | +63.28 | |
| Belgium | Dec 28, 2020 0.00 | 147.19 | +147.19 | |
| Belize | Feb 28, 2021 0.00 | Nov 29, 2021 100.70 | +100.70 | |
| Benin | May 12, 2021 0.09 | Nov 19, 2021 3.08 | +2.99 | +3,322% |
| Bermuda | Jan 10, 2021 0.00 | Nov 5, 2021 163.21 | +163.21 | |
| Bhutan | Mar 26, 2021 0.00 | Nov 21, 2021 147.88 | +147.88 | |
| Bolivia | Jan 28, 2021 0.00 | Nov 11, 2021 67.96 | +67.96 | |
| Bonaire Sint Eustatius and Saba | Apr 9, 2021 27.95 | Sep 1, 2021 135.55 | +107.60 | +385% |
| Bosnia and Herzegovina | Feb 11, 2021 0.00 | Nov 4, 2021 47.61 | +47.61 | |
| Botswana | Mar 25, 2021 0.00 | Nov 24, 2021 56.42 | +56.42 | |
| Brazil | Jan 17, 2021 0.00 | 145.22 | +145.22 | |
| British Virgin Islands | May 21, 2021 49.41 | Nov 29, 2021 114.75 | +65.34 | +132% |
| Brunei | Apr 2, 2021 0.00 | 170.42 | +170.42 | |
| Bulgaria | Dec 29, 2020 0.02 | 48.57 | +48.55 | +242,750% |
| Burkina Faso | Jun 2, 2021 0.00 | Nov 4, 2021 3.08 | +3.08 | |
| Burundi | Oct 19, 2021 0.00 | Nov 26, 2021 0.01 | +0.01 | |
| Cambodia | Feb 9, 2021 0.00 | 169.80 | +169.80 | |
| Cameroon | Apr 11, 2021 0.00 | Nov 29, 2021 3.50 | +3.50 | |
| Canada | Dec 14, 2020 0.00 | 159.66 | +159.66 | |
| Cape Verde | Mar 18, 2021 0.00 | Nov 26, 2021 96.83 | +96.83 | |
| Cayman Islands | Dec 26, 2020 0.00 | Nov 29, 2021 186.29 | +186.29 | |
| Central African Republic | May 12, 2021 0.01 | Nov 19, 2021 8.59 | +8.58 | +85,800% |
| Chad | Jun 10, 2021 0.03 | Nov 27, 2021 1.53 | +1.50 | +5,000% |
| Chile | Dec 24, 2020 0.00 | Nov 30, 2021 213.38 | +213.38 | |
| China | Dec 15, 2020 0.10 | 174.24 | +174.14 | +174,140% |
| Colombia | Feb 17, 2021 0.00 | Nov 29, 2021 111.36 | +111.36 | |
| Comoros | Apr 21, 2021 1.51 | Nov 28, 2021 58.89 | +57.38 | +3,800% |
| Congo | Apr 14, 2021 0.25 | Nov 24, 2021 11.06 | +10.81 | +4,324% |
| Cook Islands | May 25, 2021 24.83 | Nov 8, 2021 138.44 | +113.61 | +458% |
| Costa Rica | Dec 24, 2020 0.00 | Nov 29, 2021 138.90 | +138.90 | |
| Cote d’Ivoire | Mar 1, 2021 0.00 | Nov 14, 2021 14.22 | +14.22 | |
| Croatia | Dec 30, 2020 0.19 | Nov 30, 2021 101.77 | +101.58 | +53,463% |
| Cuba | May 31, 2021 18.01 | Nov 29, 2021 251.24 | +233.23 | +1,295% |
| Curacao | Mar 29, 2021 11.90 | 120.26 | +108.36 | +911% |
| Cyprus | Jan 6, 2021 0.44 | Nov 27, 2021 146.29 | +145.85 | +33,148% |
| Czechia | Dec 27, 2020 0.01 | 126.80 | +126.79 | +1,267,900% |
| Democratic Republic of Congo | Apr 18, 2021 0.00 | Nov 29, 2021 0.21 | +0.21 | |
| Denmark | Feb 10, 2021 5.86 | Nov 30, 2021 169.09 | +163.23 | +2,785% |
| Djibouti | Apr 17, 2021 1.02 | Nov 24, 2021 9.95 | +8.93 | +875% |
| Dominica | Feb 11, 2021 0.00 | Nov 29, 2021 76.93 | +76.93 | |
| Dominican Republic | Feb 15, 2021 0.00 | Nov 30, 2021 126.14 | +126.14 | |
| Ecuador | Jan 20, 2021 0.00 | Nov 29, 2021 137.87 | +137.87 | |
| Egypt | Jan 24, 2021 0.00 | Nov 28, 2021 38.28 | +38.28 | |
| El Salvador | Feb 17, 2021 0.00 | Nov 30, 2021 140.83 | +140.83 | |
| Equatorial Guinea | Mar 16, 2021 0.45 | Nov 29, 2021 30.74 | +30.29 | +6,731% |
| Estonia | Dec 27, 2020 0.01 | 111.87 | +111.86 | +1,118,600% |
| Eswatini | Mar 30, 2021 0.00 | Nov 24, 2021 26.14 | +26.14 | |
| Ethiopia | Apr 8, 2021 0.36 | 8.11 | +7.75 | +2,153% |
| Europe | 0.00 | 127.77 | +127.77 | |
| European Union | 0.00 | 143.87 | +143.87 | |
| Faeroe Islands | Jan 29, 2021 8.14 | Nov 5, 2021 159.72 | +151.58 | +1,862% |
| Falkland Islands | Feb 7, 2021 0.00 | Apr 14, 2021 124.91 | +124.91 | |
| Fiji | Mar 17, 2021 0.00 | Nov 30, 2021 137.02 | +137.02 | |
| Finland | Dec 31, 2020 0.03 | 149.97 | +149.94 | +499,800% |
| France | Dec 27, 2020 0.00 | Nov 30, 2021 156.65 | +156.65 | |
| French Polynesia | Feb 2, 2021 0.75 | Nov 30, 2021 112.83 | +112.08 | +14,944% |
| Gabon | Mar 22, 2021 0.00 | Nov 24, 2021 12.20 | +12.20 | |
| Gambia | Mar 9, 2021 0.00 | Nov 21, 2021 10.78 | +10.78 | |
| Georgia | Mar 14, 2021 0.00 | 55.23 | +55.23 | |
| Germany | Dec 27, 2020 0.03 | 148.27 | +148.24 | +494,133% |
| Ghana | Mar 1, 2021 0.00 | Nov 24, 2021 11.01 | +11.01 | |
| Gibraltar | Jan 10, 2021 1.25 | 292.13 | +290.88 | +23,270% |
| Greece | Dec 28, 2020 0.00 | 138.92 | +138.92 | |
| Greenland | Jan 27, 2021 4.54 | Nov 25, 2021 136.55 | +132.01 | +2,908% |
| Grenada | Feb 11, 2021 0.00 | Nov 29, 2021 66.10 | +66.10 | |
| Guatemala | Feb 25, 2021 0.00 | Nov 30, 2021 55.18 | +55.18 | |
| Guernsey | Jan 24, 2021 10.53 | Nov 22, 2021 164.28 | +153.75 | +1,460% |
| Guinea | Mar 31, 2021 0.46 | Nov 28, 2021 18.22 | +17.76 | +3,861% |
| Guinea-Bissau | May 12, 2021 0.29 | Nov 28, 2021 18.28 | +17.99 | +6,203% |
| Guyana | Feb 11, 2021 0.00 | 86.18 | +86.18 | |
| Haiti | Jul 16, 2021 0.00 | Nov 19, 2021 1.60 | +1.60 | |
| High income | 0.00 | 150.35 | +150.35 | |
| Honduras | Feb 28, 2021 0.03 | Nov 29, 2021 79.11 | +79.08 | +263,600% |
| Hong Kong | Feb 22, 2021 0.00 | 125.30 | +125.30 | |
| Hungary | Dec 28, 2020 0.01 | Nov 29, 2021 148.25 | +148.24 | +1,482,400% |
| Iceland | Dec 30, 2020 1.42 | Nov 30, 2021 188.90 | +187.48 | +13,203% |
| India | Jan 15, 2021 0.00 | 89.39 | +89.39 | |
| Indonesia | Jan 12, 2021 0.00 | 85.66 | +85.66 | |
| Iran | Feb 8, 2021 0.00 | Nov 27, 2021 123.03 | +123.03 | |
| Iraq | Mar 1, 2021 0.00 | Nov 28, 2021 29.26 | +29.26 | |
| Ireland | Dec 28, 2020 0.00 | 166.59 | +166.59 | |
| Isle of Man | Jan 21, 2021 4.17 | 155.90 | +151.73 | +3,639% |
| Israel | Dec 19, 2020 0.00 | 174.47 | +174.47 | |
| Italy | Dec 27, 2020 0.01 | 160.60 | +160.59 | +1,605,900% |
| Jamaica | Mar 9, 2021 0.00 | 37.48 | +37.48 | |
| Japan | Feb 17, 2021 0.00 | Nov 30, 2021 156.50 | +156.50 | |
| Jersey | Mar 14, 2021 45.27 | Nov 24, 2021 182.93 | +137.66 | +304% |
| Jordan | Jan 12, 2021 0.00 | 76.90 | +76.90 | |
| Kazakhstan | Jan 31, 2021 0.00 | 88.70 | +88.70 | |
| Kenya | Mar 4, 2021 0.00 | Nov 30, 2021 13.05 | +13.05 | |
| Kiribati | Jun 1, 2021 0.00 | Nov 30, 2021 67.69 | +67.69 | |
| Kosovo | Mar 28, 2021 0.00 | 90.76 | +90.76 | |
| Kuwait | Dec 28, 2020 0.06 | Nov 30, 2021 151.98 | +151.92 | +253,200% |
| Kyrgyzstan | Mar 28, 2021 0.00 | 30.68 | +30.68 | |
| Laos | Mar 17, 2021 0.55 | Nov 23, 2021 79.00 | +78.45 | +14,264% |
| Latvia | Dec 4, 2020 0.00 | 118.07 | +118.07 | |
| Lebanon | Feb 13, 2021 0.00 | 53.31 | +53.31 | |
| Lesotho | Mar 9, 2021 0.00 | Nov 17, 2021 28.61 | +28.61 | |
| Liberia | May 12, 2021 0.70 | Nov 18, 2021 11.38 | +10.68 | +1,526% |
| Libya | Apr 17, 2021 0.01 | Nov 28, 2021 33.57 | +33.56 | +335,600% |
| Liechtenstein | Dec 21, 2020 0.00 | Nov 30, 2021 133.63 | +133.63 | |
| Lithuania | Dec 27, 2020 0.09 | 138.33 | +138.24 | +153,600% |
| Low income | Feb 15, 2021 0.00 | 8.28 | +8.28 | |
| Lower middle income | Jan 12, 2021 0.00 | 72.00 | +72.00 | |
| Luxembourg | Dec 28, 2020 0.07 | Nov 28, 2021 144.52 | +144.45 | +206,357% |
| Macao | Feb 8, 2021 0.00 | Nov 30, 2021 139.58 | +139.58 | |
| Madagascar | May 12, 2021 0.00 | Nov 29, 2021 2.41 | +2.41 | |
| Malawi | Mar 17, 2021 0.03 | 7.29 | +7.26 | +24,200% |
| Malaysia | Feb 24, 2021 0.00 | Nov 30, 2021 163.04 | +163.04 | |
| Maldives | Feb 2, 2021 0.16 | Nov 30, 2021 142.02 | +141.86 | +88,663% |
| Mali | Mar 30, 2021 0.00 | Nov 28, 2021 4.06 | +4.06 | |
| Malta | Jan 17, 2021 2.27 | Nov 30, 2021 185.99 | +183.72 | +8,093% |
| Mauritania | Mar 26, 2021 0.00 | Nov 24, 2021 36.31 | +36.31 | |
| Mauritius | Jan 25, 2021 0.00 | Nov 23, 2021 147.25 | +147.25 | |
| Mexico | Dec 24, 2020 0.00 | 101.98 | +101.98 | |
| Moldova | Mar 5, 2021 0.10 | Nov 30, 2021 40.39 | +40.29 | +40,290% |
| Monaco | Dec 30, 2020 0.00 | Sep 16, 2021 126.47 | +126.47 | |
| Mongolia | Feb 22, 2021 0.00 | 132.54 | +132.54 | |
| Montenegro | Feb 20, 2021 0.00 | 84.65 | +84.65 | |
| Montserrat | Feb 8, 2021 0.00 | Nov 12, 2021 59.20 | +59.20 | |
| Morocco | Jan 28, 2021 0.00 | Nov 28, 2021 130.63 | +130.63 | |
| Mozambique | Mar 7, 2021 0.00 | Nov 29, 2021 31.55 | +31.55 | |
| Myanmar | Jan 26, 2021 0.00 | Nov 20, 2021 47.20 | +47.20 | |
| Namibia | Mar 18, 2021 0.00 | Nov 24, 2021 25.12 | +25.12 | |
| Nauru | Apr 8, 2021 0.00 | Aug 31, 2021 136.70 | +136.70 | |
| Nepal | Jan 26, 2021 0.00 | Nov 22, 2021 57.95 | +57.95 | |
| Netherlands | Jan 6, 2021 0.02 | Nov 29, 2021 143.46 | +143.44 | +717,200% |
| New Caledonia | Feb 2, 2021 0.39 | Nov 30, 2021 121.56 | +121.17 | +31,069% |
| New Zealand | Feb 18, 2021 0.00 | Nov 29, 2021 147.14 | +147.14 | |
| Nicaragua | Mar 1, 2021 0.00 | 95.13 | +95.13 | |
| Niger | Mar 28, 2021 0.00 | Nov 28, 2021 3.87 | +3.87 | |
| Nigeria | Mar 4, 2021 0.00 | Nov 25, 2021 4.66 | +4.66 | |
| Niue | Jun 21, 2021 0.00 | Aug 2, 2021 145.72 | +145.72 | |
| North America | Dec 13, 2020 0.00 | 125.61 | +125.61 | |
| North Macedonia | Feb 16, 2021 0.00 | Nov 22, 2021 80.46 | +80.46 | |
| Northern Cyprus | Jan 14, 2021 0.00 | Nov 26, 2021 161.52 | +161.52 | |
| Norway | Dec 2, 2020 0.00 | Nov 30, 2021 158.61 | +158.61 | |
| Oceania | Feb 2, 2021 0.01 | 116.01 | +116.00 | +1,160,000% |
| Oman | Dec 28, 2020 0.03 | Nov 23, 2021 113.62 | +113.59 | +378,633% |
| Pakistan | Feb 2, 2021 0.00 | 55.09 | +55.09 | |
| Palestine | Mar 30, 2021 1.57 | Nov 22, 2021 57.91 | +56.34 | +3,589% |
| Panama | Jan 20, 2021 0.01 | 128.27 | +128.26 | +1,282,600% |
| Papua New Guinea | Mar 30, 2021 0.00 | Nov 30, 2021 5.12 | +5.12 | |
| Paraguay | Feb 22, 2021 0.00 | Nov 29, 2021 83.94 | +83.94 | |
| Peru | Feb 8, 2021 0.00 | Nov 30, 2021 125.43 | +125.43 | |
| Philippines | Feb 28, 2021 0.00 | 80.21 | +80.21 | |
| Pitcairn | Jun 15, 2021 100.00 | Sep 7, 2021 200.00 | +100.00 | +100% |
| Poland | Dec 28, 2020 0.01 | 111.21 | +111.20 | +1,112,000% |
| Portugal | Dec 27, 2020 0.05 | Nov 15, 2021 160.39 | +160.34 | +320,680% |
| Qatar | Dec 22, 2020 0.00 | 170.26 | +170.26 | |
| Romania | Dec 27, 2020 0.01 | Nov 30, 2021 78.04 | +78.03 | +780,300% |
| Russia | Dec 15, 2020 0.02 | 87.41 | +87.39 | +436,950% |
| Rwanda | Feb 15, 2021 0.00 | Nov 24, 2021 65.89 | +65.89 | |
| Saint Helena | Feb 3, 2021 1.76 | May 5, 2021 129.48 | +127.72 | +7,257% |
| Saint Kitts and Nevis | Feb 22, 2021 0.00 | Nov 29, 2021 97.83 | +97.83 | |
| Saint Lucia | Feb 16, 2021 0.00 | 54.80 | +54.80 | |
| Saint Vincent and the Grenadines | Mar 17, 2021 8.05 | Nov 27, 2021 48.95 | +40.90 | +508% |
| Samoa | May 4, 2021 3.70 | Nov 30, 2021 124.28 | +120.58 | +3,259% |
| San Marino | Feb 27, 2021 0.10 | Nov 21, 2021 140.58 | +140.48 | +140,480% |
| Sao Tome and Principe | Mar 15, 2021 0.00 | Nov 26, 2021 54.33 | +54.33 | |
| Saudi Arabia | Jan 6, 2021 0.39 | 134.26 | +133.87 | +34,326% |
| Senegal | Feb 22, 2021 0.00 | Nov 26, 2021 11.11 | +11.11 | |
| Serbia | Jan 8, 2021 0.10 | Nov 30, 2021 114.96 | +114.86 | +114,860% |
| Seychelles | Jan 9, 2021 0.00 | Nov 29, 2021 181.44 | +181.44 | |
| Sierra Leone | Mar 14, 2021 0.00 | Nov 26, 2021 10.67 | +10.67 | |
| Singapore | Jan 11, 2021 0.06 | Nov 5, 2021 184.89 | +184.83 | +308,050% |
| Sint Maarten (Dutch part) | May 7, 2021 56.73 | Nov 29, 2021 119.06 | +62.33 | +110% |
| Slovakia | Jan 4, 2021 0.01 | 91.38 | +91.37 | +913,700% |
| Slovenia | Dec 27, 2020 0.30 | 129.32 | +129.02 | +43,007% |
| Solomon Islands | Mar 23, 2021 0.00 | Nov 30, 2021 29.55 | +29.55 | |
| Somalia | Apr 17, 2021 0.72 | Nov 13, 2021 5.90 | +5.18 | +719% |
| South Africa | Feb 16, 2021 0.00 | 42.94 | +42.94 | |
| South America | Dec 24, 2020 0.00 | 136.46 | +136.46 | |
| South Korea | Feb 26, 2021 0.06 | Nov 30, 2021 166.36 | +166.30 | +277,167% |
| South Sudan | Apr 5, 2021 0.00 | Nov 23, 2021 1.92 | +1.92 | |
| Spain | Jan 4, 2021 0.18 | Nov 30, 2021 164.04 | +163.86 | +91,033% |
| Sri Lanka | Jan 28, 2021 0.00 | 138.07 | +138.07 | |
| Sudan | Mar 10, 2021 0.00 | Oct 20, 2021 3.70 | +3.70 | |
| Suriname | Feb 22, 2021 0.00 | 80.58 | +80.58 | |
| Sweden | Jan 3, 2021 0.02 | 156.44 | +156.42 | +782,100% |
| Switzerland | Dec 21, 2020 0.00 | Nov 30, 2021 136.71 | +136.71 | |
| Syria | Mar 1, 2021 0.00 | Nov 28, 2021 7.78 | +7.78 | |
| Taiwan | Mar 21, 2021 0.00 | 133.35 | +133.35 | |
| Tajikistan | May 7, 2021 0.71 | Nov 21, 2021 54.28 | +53.57 | +7,545% |
| Tanzania | Aug 8, 2021 0.17 | Oct 29, 2021 1.63 | +1.46 | +859% |
| Thailand | Feb 27, 2021 0.00 | 133.28 | +133.28 | |
| Timor | Apr 14, 2021 0.20 | Nov 23, 2021 79.47 | +79.27 | +39,635% |
| Togo | Mar 9, 2021 0.00 | Nov 26, 2021 19.64 | +19.64 | |
| Tokelau | Jun 21, 2021 0.00 | Oct 12, 2021 141.52 | +141.52 | |
| Tonga | Apr 20, 2021 2.14 | Nov 30, 2021 110.70 | +108.56 | +5,073% |
| Trinidad and Tobago | Feb 15, 2021 0.00 | 91.99 | +91.99 | |
| Tunisia | Mar 12, 2021 0.00 | Nov 30, 2021 88.48 | +88.48 | |
| Turkey | Jan 13, 2021 0.00 | 141.71 | +141.71 | |
| Turkmenistan | Feb 28, 2021 0.85 | Aug 29, 2021 123.91 | +123.06 | +14,478% |
| Turks and Caicos Islands | Jan 10, 2021 0.00 | Nov 5, 2021 143.64 | +143.64 | |
| Tuvalu | Apr 27, 2021 20.13 | Oct 22, 2021 101.58 | +81.45 | +405% |
| Uganda | Mar 9, 2021 0.00 | Nov 15, 2021 10.08 | +10.08 | |
| Ukraine | Feb 24, 2021 0.00 | 57.41 | +57.41 | |
| United Arab Emirates | Jan 5, 2021 8.27 | Nov 15, 2021 215.68 | +207.41 | +2,508% |
| United Kingdom | Jan 10, 2021 3.93 | Nov 30, 2021 170.07 | +166.14 | +4,227% |
| United States | Dec 13, 2020 0.01 | 137.45 | +137.44 | +1,374,400% |
| Upper middle income | Dec 15, 2020 0.06 | 150.59 | +150.53 | +250,883% |
| Uruguay | Feb 27, 2021 0.01 | 195.01 | +195.00 | +1,950,000% |
| Uzbekistan | Mar 31, 2021 0.00 | Nov 30, 2021 99.22 | +99.22 | |
| Vanuatu | Jun 1, 2021 0.00 | Nov 22, 2021 41.21 | +41.21 | |
| Venezuela | Feb 17, 2021 0.00 | Nov 29, 2021 91.67 | +91.67 | |
| Vietnam | Mar 7, 2021 0.00 | Nov 29, 2021 124.36 | +124.36 | |
| Wallis and Futuna | Mar 23, 2021 11.59 | Nov 30, 2021 107.62 | +96.03 | +829% |
| World | 0.00 | 102.41 | +102.41 | |
| Yemen | May 9, 2021 0.06 | Nov 28, 2021 2.54 | +2.48 | +4,133% |
| Zambia | Apr 14, 2021 0.00 | Nov 29, 2021 5.74 | +5.74 | |
| Zimbabwe | Feb 18, 2021 0.00 | 44.00 | +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
