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1.
MMWR Morb Mortal Wkly Rep ; 71(9): 352-358, 2022 Mar 04.
Article in English | MEDLINE | ID: covidwho-1727017

ABSTRACT

The efficacy of the BNT162b2 (Pfizer-BioNTech) vaccine against laboratory-confirmed COVID-19 exceeded 90% in clinical trials that included children and adolescents aged 5-11, 12-15, and 16-17 years (1-3). Limited real-world data on 2-dose mRNA vaccine effectiveness (VE) in persons aged 12-17 years (referred to as adolescents in this report) have also indicated high levels of protection against SARS-CoV-2 (the virus that causes COVID-19) infection and COVID-19-associated hospitalization (4-6); however, data on VE against the SARS-CoV-2 B.1.1.529 (Omicron) variant and duration of protection are limited. Pfizer-BioNTech VE data are not available for children aged 5-11 years. In partnership with CDC, the VISION Network* examined 39,217 emergency department (ED) and urgent care (UC) encounters and 1,699 hospitalizations† among persons aged 5-17 years with COVID-19-like illness across 10 states during April 9, 2021-January 29, 2022,§ to estimate VE using a case-control test-negative design. Among children aged 5-11 years, VE against laboratory-confirmed COVID-19-associated ED and UC encounters 14-67 days after dose 2 (the longest interval after dose 2 in this age group) was 46%. Among adolescents aged 12-15 and 16-17 years, VE 14-149 days after dose 2 was 83% and 76%, respectively; VE ≥150 days after dose 2 was 38% and 46%, respectively. Among adolescents aged 16-17 years, VE increased to 86% ≥7 days after dose 3 (booster dose). VE against COVID-19-associated ED and UC encounters was substantially lower during the Omicron predominant period than the B.1.617.2 (Delta) predominant period among adolescents aged 12-17 years, with no significant protection ≥150 days after dose 2 during Omicron predominance. However, in adolescents aged 16-17 years, VE during the Omicron predominant period increased to 81% ≥7 days after a third booster dose. During the full study period, including pre-Delta, Delta, and Omicron predominant periods, VE against laboratory-confirmed COVID-19-associated hospitalization among children aged 5-11 years was 74% 14-67 days after dose 2, with wide CIs that included zero. Among adolescents aged 12-15 and 16-17 years, VE 14-149 days after dose 2 was 92% and 94%, respectively; VE ≥150 days after dose 2 was 73% and 88%, respectively. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations, including a booster dose for those aged 12-17 years.


Subject(s)
/administration & dosage , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , SARS-CoV-2/immunology , /statistics & numerical data , Adolescent , Ambulatory Care/statistics & numerical data , Child , Child, Preschool , Emergency Service, Hospital/statistics & numerical data , Female , Hospitalization/statistics & numerical data , Humans , Immunization, Secondary , Male , United States
2.
MMWR Morb Mortal Wkly Rep ; 71(7): 255-263, 2022 Feb 18.
Article in English | MEDLINE | ID: covidwho-1689713

ABSTRACT

CDC recommends that all persons aged ≥12 years receive a booster dose of COVID-19 mRNA vaccine ≥5 months after completion of a primary mRNA vaccination series and that immunocompromised persons receive a third primary dose.* Waning of vaccine protection after 2 doses of mRNA vaccine has been observed during the period of the SARS-CoV-2 B.1.617.2 (Delta) variant predominance† (1-5), but little is known about durability of protection after 3 doses during periods of Delta or SARS-CoV-2 B.1.1.529 (Omicron) variant predominance. A test-negative case-control study design using data from eight VISION Network sites§ examined vaccine effectiveness (VE) against COVID-19 emergency department/urgent care (ED/UC) visits and hospitalizations among U.S. adults aged ≥18 years at various time points after receipt of a second or third vaccine dose during two periods: Delta variant predominance and Omicron variant predominance (i.e., periods when each variant accounted for ≥50% of sequenced isolates).¶ Persons categorized as having received 3 doses included those who received a third dose in a primary series or a booster dose after a 2 dose primary series (including the reduced-dosage Moderna booster). The VISION Network analyzed 241,204 ED/UC encounters** and 93,408 hospitalizations across 10 states during August 26, 2021-January 22, 2022. VE after receipt of both 2 and 3 doses was lower during the Omicron-predominant than during the Delta-predominant period at all time points evaluated. During both periods, VE after receipt of a third dose was higher than that after a second dose; however, VE waned with increasing time since vaccination. During the Omicron period, VE against ED/UC visits was 87% during the first 2 months after a third dose and decreased to 66% among those vaccinated 4-5 months earlier; VE against hospitalizations was 91% during the first 2 months following a third dose and decreased to 78% ≥4 months after a third dose. For both Delta- and Omicron-predominant periods, VE was generally higher for protection against hospitalizations than against ED/UC visits. All eligible persons should remain up to date with recommended COVID-19 vaccinations to best protect against COVID-19-associated hospitalizations and ED/UC visits.


Subject(s)
Ambulatory Care/statistics & numerical data , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Hospitalization/statistics & numerical data , SARS-CoV-2/immunology , /administration & dosage , Adult , Aged , Aged, 80 and over , Case-Control Studies , Emergency Service, Hospital , Female , Humans , Male , Middle Aged , Time Factors , United States , Young Adult
4.
MMWR Morb Mortal Wkly Rep ; 70(44): 1553-1559, 2021 Nov 05.
Article in English | MEDLINE | ID: covidwho-1502903

ABSTRACT

Immunocompromised persons, defined as those with suppressed humoral or cellular immunity resulting from health conditions or medications, account for approximately 3% of the U.S. adult population (1). Immunocompromised adults are at increased risk for severe COVID-19 outcomes (2) and might not acquire the same level of protection from COVID-19 mRNA vaccines as do immunocompetent adults (3,4). To evaluate vaccine effectiveness (VE) among immunocompromised adults, data from the VISION Network* on hospitalizations among persons aged ≥18 years with COVID-19-like illness from 187 hospitals in nine states during January 17-September 5, 2021 were analyzed. Using selected discharge diagnoses,† VE against COVID-19-associated hospitalization conferred by completing a 2-dose series of an mRNA COVID-19 vaccine ≥14 days before the index hospitalization date§ (i.e., being fully vaccinated) was evaluated using a test-negative design comparing 20,101 immunocompromised adults (10,564 [53%] of whom were fully vaccinated) and 69,116 immunocompetent adults (29,456 [43%] of whom were fully vaccinated). VE of 2 doses of mRNA COVID-19 vaccine against COVID-19-associated hospitalization was lower among immunocompromised patients (77%; 95% confidence interval [CI] = 74%-80%) than among immunocompetent patients (90%; 95% CI = 89%-91%). This difference persisted irrespective of mRNA vaccine product, age group, and timing of hospitalization relative to SARS-CoV-2 (the virus that causes COVID-19) B.1.617.2 (Delta) variant predominance in the state of hospitalization. VE varied across immunocompromising condition subgroups, ranging from 59% (organ or stem cell transplant recipients) to 81% (persons with a rheumatologic or inflammatory disorder). Immunocompromised persons benefit from mRNA COVID-19 vaccination but are less protected from severe COVID-19 outcomes than are immunocompetent persons, and VE varies among immunocompromised subgroups. Immunocompromised persons receiving mRNA COVID-19 vaccines should receive 3 doses and a booster, consistent with CDC recommendations (5), practice nonpharmaceutical interventions, and, if infected, be monitored closely and considered early for proven therapies that can prevent severe outcomes.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Hospitalization/statistics & numerical data , Immunocompromised Host/immunology , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/immunology , COVID-19/therapy , COVID-19 Vaccines/immunology , Female , Humans , Immunization Schedule , Laboratories , Male , Middle Aged , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , United States/epidemiology , Vaccines, Synthetic/administration & dosage , Young Adult
5.
MMWR Morb Mortal Wkly Rep ; 70(44): 1539-1544, 2021 Nov 05.
Article in English | MEDLINE | ID: covidwho-1502901

ABSTRACT

Previous infection with SARS-CoV-2 (the virus that causes COVID-19) or COVID-19 vaccination can provide immunity and protection from subsequent SARS-CoV-2 infection and illness. CDC used data from the VISION Network* to examine hospitalizations in adults with COVID-19-like illness and compared the odds of receiving a positive SARS-CoV-2 test result, and thus having laboratory-confirmed COVID-19, between unvaccinated patients with a previous SARS-CoV-2 infection occurring 90-179 days before COVID-19-like illness hospitalization, and patients who were fully vaccinated with an mRNA COVID-19 vaccine 90-179 days before hospitalization with no previous documented SARS-CoV-2 infection. Hospitalized adults aged ≥18 years with COVID-19-like illness were included if they had received testing at least twice: once associated with a COVID-19-like illness hospitalization during January-September 2021 and at least once earlier (since February 1, 2020, and ≥14 days before that hospitalization). Among COVID-19-like illness hospitalizations in persons whose previous infection or vaccination occurred 90-179 days earlier, the odds of laboratory-confirmed COVID-19 (adjusted for sociodemographic and health characteristics) among unvaccinated, previously infected adults were higher than the odds among fully vaccinated recipients of an mRNA COVID-19 vaccine with no previous documented infection (adjusted odds ratio [aOR] = 5.49; 95% confidence interval [CI] = 2.75-10.99). These findings suggest that among hospitalized adults with COVID-19-like illness whose previous infection or vaccination occurred 90-179 days earlier, vaccine-induced immunity was more protective than infection-induced immunity against laboratory-confirmed COVID-19. All eligible persons should be vaccinated against COVID-19 as soon as possible, including unvaccinated persons previously infected with SARS-CoV-2.


Subject(s)
COVID-19/diagnosis , COVID-19/immunology , SARS-CoV-2/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/therapy , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Female , Hospitalization/statistics & numerical data , Humans , Laboratories , Male , Middle Aged , SARS-CoV-2/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology , Young Adult
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