CDC study finds Pfizer, Moderna vaccines are 90% effective after two doses in real-world conditions

Under real world conditions, the Pfizer and Moderna Covid-19 vaccines provide highly effective protection, according to a new report from the...

Posted: Mar 29, 2021 4:15 PM
Updated: Mar 29, 2021 11:15 PM

Under real world conditions, the Pfizer and Moderna Covid-19 vaccines provide highly effective protection, according to a new report from the US Centers for Disease Control and Prevention.

At full vaccination, the vaccines were 90% effective at preventing infections, including infections that had no symptoms. At least 14 days after first dose but before second dose, they were 80% protective, according to the agency's Morbidity and Mortality Weekly Report published Monday. The CDC said it is the first of many planned Covid-19 vaccine effectiveness studies.

The study looked at how the vaccines protected nearly 4,000 health care workers and first responders. The volunteers in the study worked in eight locations around the country and had been observed from mid-December to mid-March.

The CDC tested volunteers routinely regardless of symptoms. The CDC also monitored the volunteers through text message, e-mail and direct medical reports. The volunteers also did a nasal swab once a week.

Most of the volunteers, more than 62%, had received both doses of either a Pfizer or Moderna Covid-19 vaccine. More than 12% had received just a single dose.

Among the 2,961 people vaccinated with one or more doses and the 989 unvaccinated participants, a total of 205 had a positive PCR test for Covid-19. One hundred sixty-one infections were identified when participants were unvaccinated; eight were identified among those partially immunized and three were identified among those fully immunized -- more than 14 days after their second dose of vaccine. Thirty-three identified cases were excluded because the person's immune status was not clear.

More than 87% of Covid-19 cases had symptoms. Nearly 23% of the cases sought help from a doctor. There were two hospitalizations, but no deaths.

The results of this study are similar to what scientists saw in clinical trials for the vaccines, but studies like this are important to show how effective the vaccines are, particularly in a population that, through their work, can encounters a large number of people who have Covid-19.

The results showing the level of protection from a single dose after two weeks are similar to findings from other recent studies in the UK and Israel.

'Reducing the risk for transmissible infection, which can occur among persons with asymptomatic infection or among persons several days before symptoms onset, is especially important among health care personnel, first responders, and other essential and frontline workers given their potential to transmit the virus through frequent close contact with patients and the public,' the report concluded.

'This study is tremendously encouraging,' CDC Director Dr. Rochelle Walensky said Monday at the White House Covid-19 briefing. 'These findings also underscore the importance of getting both of the recommended doses of the vaccine in order to get the greatest level of protection against Covid-19, especially as our concerns about variants escalate.'

'Our national vaccination efforts are working,' Walensky added.

The US has made a big push to get people vaccinated. As of Monday, nearly 29% of the US population -- more than 95 million people -- have received at least one dose, and nearly 16% of the population -- about 52.6 million people -- are fully vaccinated, CDC data shows. Among those 18 and older, more than 1 in 5 are fully vaccinated.

'Get vaccinated when you can,' Walensky said. 'So that all those people that we all love will still be here when this pandemic ends.'

Mississippi Coronavirus Cases

Data is updated nightly.

Cases: 343505

Reported Deaths: 7543
CountyCasesDeaths
Hinds23932444
DeSoto23229283
Harrison20527329
Rankin15411291
Jackson15232252
Madison10959227
Lee10719179
Jones9047169
Forrest8723159
Lauderdale7884244
Lowndes7054151
Lamar702989
Lafayette6548124
Washington5595139
Pearl River5196152
Bolivar4954134
Oktibbeha494398
Panola4771112
Warren4728128
Marshall4701106
Pontotoc447773
Union433279
Monroe4330137
Neshoba4281181
Hancock428088
Lincoln4176116
Pike3667113
Leflore3627125
Tate353388
Alcorn350974
Sunflower347694
Scott341176
Adams340988
Yazoo339376
Copiah324968
Simpson322891
Itawamba314680
Coahoma314085
Tippah306568
Prentiss298863
Covington293484
Leake285475
Marion284181
Wayne277543
George272251
Grenada269488
Newton262364
Tishomingo239770
Winston236784
Jasper230648
Stone229637
Attala226373
Chickasaw219060
Holmes200174
Clay197654
Clarke186880
Tallahatchie183742
Calhoun181332
Smith179235
Yalobusha171540
Walthall145748
Lawrence142826
Greene140134
Amite137543
Noxubee135235
Perry133538
Montgomery133044
Carroll126431
Webster121232
Jefferson Davis116734
Tunica114227
Benton106725
Claiborne105331
Kemper102429
Humphreys100133
Franklin87923
Quitman84719
Choctaw82619
Wilkinson78032
Jefferson71328
Sharkey51618
Issaquena1736
Unassigned00

Alabama Coronavirus Cases

Cases: 587405

Reported Deaths: 11536
CountyCasesDeaths
Jefferson853851591
Mobile48932864
Madison37517533
Shelby27280257
Tuscaloosa27171465
Montgomery26172627
Baldwin25399329
Lee17224181
Calhoun15401334
Morgan15170291
Etowah14954370
Marshall13116235
Houston12077293
Elmore10915219
St. Clair10763252
Limestone10725158
Cullman10546205
Lauderdale10255254
DeKalb9508192
Talladega8949188
Walker7793288
Autauga7563114
Jackson7400117
Blount7362139
Colbert6703142
Coffee6365132
Dale5650117
Russell480243
Chilton4771117
Covington4749125
Franklin458181
Tallapoosa4519156
Escambia441383
Chambers3949125
Dallas3743163
Clarke371263
Marion3463107
Pike332579
Lawrence3263100
Winston298773
Bibb290465
Geneva283983
Marengo262467
Barbour250961
Pickens245562
Butler240872
Hale235578
Fayette227065
Henry213945
Monroe202141
Randolph201144
Cherokee199248
Washington185239
Macon170552
Crenshaw168358
Clay166259
Cleburne161345
Lamar151038
Lowndes145455
Wilcox132331
Bullock126542
Conecuh121332
Coosa118329
Perry110528
Sumter110333
Greene99137
Choctaw64425
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The heat wave that controlled our area over the past several days is now behind us. The forecast for the next week looks a bit cooler & less humid.
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