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1.
Clin Infect Dis ; 2021 Dec 20.
Article in English | MEDLINE | ID: covidwho-1722268

ABSTRACT

BACKGROUND: Data on the development of neutralizing antibodies against SARS-CoV-2 after SARS-CoV-2 infection and after vaccination with messenger RNA (mRNA) COVID-19 vaccines are limited. METHODS: From a prospective cohort of 3,975 adult essential and frontline workers tested weekly from August 2020 to March 2021 for SARS-CoV-2 infection by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assay irrespective of symptoms, 497 participants had sera drawn after infection (170), vaccination (327), and after both infection and vaccination (50 from the infection population). Serum was collected after infection and each vaccine dose. Serum-neutralizing antibody titers against USA-WA1/2020-spike pseudotype virus were determined by the 50% inhibitory dilution. Geometric mean titers (GMTs) and corresponding fold increases were calculated using t-tests and linear mixed effects models. RESULTS: Among 170 unvaccinated participants with SARS-CoV-2 infection, 158 (93%) developed neutralizing antibodies (nAb) with a GMT of 1,003 (95% CI=766-1,315). Among 139 previously uninfected participants, 138 (99%) developed nAb after mRNA vaccine dose-2 with a GMT of 3,257 (95% CI = 2,596-4,052). GMT was higher among those receiving mRNA-1273 vaccine (GMT =4,698, 95%CI= 3,186-6,926) compared to BNT162b2 vaccine (GMT=2,309, 95%CI=1,825-2,919). Among 32 participants with prior SARS-CoV-2 infection, GMT was 21,655 (95%CI=14,766-31,756) after mRNA vaccine dose-1, without further increase after dose-2. CONCLUSIONS: A single dose of mRNA vaccine after SARS-CoV-2 infection resulted in the highest observed nAb response. Two doses of mRNA vaccine in previously uninfected participants resulted in higher nAb to SARS-CoV-2 than after one dose of vaccine or SARS-CoV-2 infection alone. Neutralizing antibody response also differed by mRNA vaccine product.

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(46): 1608-1612, 2021 Nov 19.
Article in English | MEDLINE | ID: covidwho-1524680

ABSTRACT

Population-based rates of infection with SARS-CoV-2 (the virus that causes COVID-19) and related health care utilization help determine estimates of COVID-19 vaccine effectiveness and averted illnesses, especially since the SARS-CoV-2 B.1.617.2 (Delta) variant began circulating in June 2021. Among members aged ≥12 years of a large integrated health care delivery system in Oregon and Washington, incidence of laboratory-confirmed SARS-CoV-2 infection, emergency department (ED) visits, and hospitalizations were calculated by COVID-19 vaccination status, vaccine product, age, race, and ethnicity. Infection after full vaccination was defined as a positive SARS-CoV-2 molecular test result ≥14 days after completion of an authorized COVID-19 vaccination series.* During the July-September 2021 surveillance period, SARS-CoV-2 infection occurred among 4,146 of 137,616 unvaccinated persons (30.1 per 1,000 persons) and 3,009 of 344,848 fully vaccinated persons (8.7 per 1,000). Incidence was higher among unvaccinated persons than among vaccinated persons across all demographic strata. Unvaccinated persons with SARS-CoV-2 infection were more than twice as likely to receive ED care (18.5%) or to be hospitalized (9.0%) than were vaccinated persons with COVID-19 (8.1% and 3.9%, respectively). The crude mortality rate was also higher among unvaccinated patients (0.43 per 1,000) than in fully vaccinated patients (0.06 per 1,000). These data support CDC recommendations for COVID-19 vaccination, including additional and booster doses, to protect individual persons and communities against COVID-19, including illness and hospitalization caused by the Delta variant (1).


Subject(s)
COVID-19/epidemiology , COVID-19/therapy , Emergency Service, Hospital/statistics & numerical data , Hospitalization/statistics & numerical data , Adolescent , Adult , Aged , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , Child , Female , Humans , Incidence , Male , Middle Aged , Oregon/epidemiology , Vaccination/statistics & numerical data , Washington/epidemiology , Young Adult
5.
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
6.
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
7.
N Engl J Med ; 385(15): 1355-1371, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1397961

ABSTRACT

BACKGROUND: There are limited data on the effectiveness of the vaccines against symptomatic coronavirus disease 2019 (Covid-19) currently authorized in the United States with respect to hospitalization, admission to an intensive care unit (ICU), or ambulatory care in an emergency department or urgent care clinic. METHODS: We conducted a study involving adults (≥50 years of age) with Covid-19-like illness who underwent molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed 41,552 admissions to 187 hospitals and 21,522 visits to 221 emergency departments or urgent care clinics during the period from January 1 through June 22, 2021, in multiple states. The patients' vaccination status was documented in electronic health records and immunization registries. We used a test-negative design to estimate vaccine effectiveness by comparing the odds of a positive test for SARS-CoV-2 infection among vaccinated patients with those among unvaccinated patients. Vaccine effectiveness was adjusted with weights based on propensity-for-vaccination scores and according to age, geographic region, calendar time (days from January 1, 2021, to the index date for each medical visit), and local virus circulation. RESULTS: The effectiveness of full messenger RNA (mRNA) vaccination (≥14 days after the second dose) was 89% (95% confidence interval [CI], 87 to 91) against laboratory-confirmed SARS-CoV-2 infection leading to hospitalization, 90% (95% CI, 86 to 93) against infection leading to an ICU admission, and 91% (95% CI, 89 to 93) against infection leading to an emergency department or urgent care clinic visit. The effectiveness of full vaccination with respect to a Covid-19-associated hospitalization or emergency department or urgent care clinic visit was similar with the BNT162b2 and mRNA-1273 vaccines and ranged from 81% to 95% among adults 85 years of age or older, persons with chronic medical conditions, and Black or Hispanic adults. The effectiveness of the Ad26.COV2.S vaccine was 68% (95% CI, 50 to 79) against laboratory-confirmed SARS-CoV-2 infection leading to hospitalization and 73% (95% CI, 59 to 82) against infection leading to an emergency department or urgent care clinic visit. CONCLUSIONS: Covid-19 vaccines in the United States were highly effective against SARS-CoV-2 infection requiring hospitalization, ICU admission, or an emergency department or urgent care clinic visit. This vaccine effectiveness extended to populations that are disproportionately affected by SARS-CoV-2 infection. (Funded by the Centers for Disease Control and Prevention.).


Subject(s)
Ambulatory Care/statistics & numerical data , COVID-19 Vaccines , COVID-19/prevention & control , Hospitalization/statistics & numerical data , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19 Vaccines/immunology , Female , Humans , Intensive Care Units/statistics & numerical data , Male , Middle Aged , Patient Readmission/statistics & numerical data , United States/epidemiology
8.
MMWR Recomm Rep ; 70(5): 1-28, 2021 08 27.
Article in English | MEDLINE | ID: covidwho-1377134

ABSTRACT

This report updates the 2020-21 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines in the United States (MMWR Recomm Rep 2020;69[No. RR-8]). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For each recipient, a licensed and age-appropriate vaccine should be used. ACIP makes no preferential recommendation for a specific vaccine when more than one licensed, recommended, and age-appropriate vaccine is available. During the 2021-22 influenza season, the following types of vaccines are expected to be available: inactivated influenza vaccines (IIV4s), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4).The 2021-22 influenza season is expected to coincide with continued circulation of SARS-CoV-2, the virus that causes COVID-19. Influenza vaccination of persons aged ≥6 months to reduce prevalence of illness caused by influenza will reduce symptoms that might be confused with those of COVID-19. Prevention of and reduction in the severity of influenza illness and reduction of outpatient visits, hospitalizations, and intensive care unit admissions through influenza vaccination also could alleviate stress on the U.S. health care system. Guidance for vaccine planning during the pandemic is available at https://www.cdc.gov/vaccines/pandemic-guidance/index.html. Recommendations for the use of COVID-19 vaccines are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html, and additional clinical guidance is available at https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html.Updates described in this report reflect discussions during public meetings of ACIP that were held on October 28, 2020; February 25, 2021; and June 24, 2021. Primary updates to this report include the following six items. First, all seasonal influenza vaccines available in the United States for the 2021-22 season are expected to be quadrivalent. Second, the composition of 2021-22 U.S. influenza vaccines includes updates to the influenza A(H1N1)pdm09 and influenza A(H3N2) components. U.S.-licensed influenza vaccines will contain hemagglutinin derived from an influenza A/Victoria/2570/2019 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/588/2019 (H1N1)pdm09-like virus (for cell culture-based and recombinant vaccines), an influenza A/Cambodia/e0826360/2020 (H3N2)-like virus, an influenza B/Washington/02/2019 (Victoria lineage)-like virus, and an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus. Third, the approved age indication for the cell culture-based inactivated influenza vaccine, Flucelvax Quadrivalent (ccIIV4), has been expanded from ages ≥4 years to ages ≥2 years. Fourth, discussion of administration of influenza vaccines with other vaccines includes considerations for coadministration of influenza vaccines and COVID-19 vaccines. Providers should also consult current ACIP COVID-19 vaccine recommendations and CDC guidance concerning coadministration of these vaccines with influenza vaccines. Vaccines that are given at the same time should be administered in separate anatomic sites. Fifth, guidance concerning timing of influenza vaccination now states that vaccination soon after vaccine becomes available can be considered for pregnant women in the third trimester. As previously recommended, children who need 2 doses (children aged 6 months through 8 years who have never received influenza vaccine or who have not previously received a lifetime total of ≥2 doses) should receive their first dose as soon as possible after vaccine becomes available to allow the second dose (which must be administered ≥4 weeks later) to be received by the end of October. For nonpregnant adults, vaccination in July and August should be avoided unless there is concern that later vaccination might not be possible. Sixth, contraindications and precautions to the use of ccIIV4 and RIV4 have been modified, specifically with regard to persons with a history of severe allergic reaction (e.g., anaphylaxis) to an influenza vaccine. A history of a severe allergic reaction to a previous dose of any egg-based IIV, LAIV, or RIV of any valency is a precaution to use of ccIIV4. A history of a severe allergic reaction to a previous dose of any egg-based IIV, ccIIV, or LAIV of any valency is a precaution to use of RIV4. Use of ccIIV4 and RIV4 in such instances should occur in an inpatient or outpatient medical setting under supervision of a provider who can recognize and manage a severe allergic reaction; providers can also consider consulting with an allergist to help identify the vaccine component responsible for the reaction. For ccIIV4, history of a severe allergic reaction (e.g., anaphylaxis) to any ccIIV of any valency or any component of ccIIV4 is a contraindication to future use of ccIIV4. For RIV4, history of a severe allergic reaction (e.g., anaphylaxis) to any RIV of any valency or any component of RIV4 is a contraindication to future use of RIV4. This report focuses on recommendations for the use of vaccines for the prevention and control of seasonal influenza during the 2021-22 influenza season in the United States. A brief summary of the recommendations and a link to the most recent Background Document containing additional information are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html. These recommendations apply to U.S.-licensed influenza vaccines used according to Food and Drug Administration-licensed indications. Updates and other information are available from CDC's influenza website (https://www.cdc.gov/flu); vaccination and health care providers should check this site periodically for additional information.


Subject(s)
Immunization/standards , Influenza Vaccines/administration & dosage , Influenza, Human/prevention & control , Practice Guidelines as Topic , Adolescent , Adult , Advisory Committees , Aged , COVID-19/epidemiology , Centers for Disease Control and Prevention, U.S. , Child , Child, Preschool , Female , Humans , Immunization Schedule , Infant , Influenza, Human/epidemiology , Male , Middle Aged , Pregnancy , Seasons , United States/epidemiology , Young Adult
9.
MMWR Recomm Rep ; 69(8): 1-24, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-727540

ABSTRACT

This report updates the 2019-20 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines in the United States (MMWR Recomm Rep 2019;68[No. RR-3]). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For each recipient, a licensed and age-appropriate vaccine should be used. Inactivated influenza vaccines (IIVs), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4) are expected to be available. Most influenza vaccines available for the 2020-21 season will be quadrivalent, with the exception of MF59-adjuvanted IIV, which is expected to be available in both quadrivalent and trivalent formulations.Updates to the recommendations described in this report reflect discussions during public meetings of ACIP held on October 23, 2019; February 26, 2020; and June 24, 2020. Primary updates to this report include the following two items. First, the composition of 2020-21 U.S. influenza vaccines includes updates to the influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B/Victoria lineage components. Second, recent licensures of two new influenza vaccines, Fluzone High-Dose Quadrivalent and Fluad Quadrivalent, are discussed. Both new vaccines are licensed for persons aged ≥65 years. Additional changes include updated discussion of contraindications and precautions to influenza vaccination and the accompanying Table, updated discussion concerning use of LAIV4 in the setting of influenza antiviral medication use, and updated recommendations concerning vaccination of persons with egg allergy who receive either cell culture-based IIV4 (ccIIV4) or RIV4.The 2020-21 influenza season will coincide with the continued or recurrent circulation of SARS-CoV-2 (the novel coronavirus associated with coronavirus disease 2019 [COVID-19]). Influenza vaccination of persons aged ≥6 months to reduce prevalence of illness caused by influenza will reduce symptoms that might be confused with those of COVID-19. Prevention of and reduction in the severity of influenza illness and reduction of outpatient illnesses, hospitalizations, and intensive care unit admissions through influenza vaccination also could alleviate stress on the U.S. health care system. Guidance for vaccine planning during the pandemic is available at https://www.cdc.gov/vaccines/pandemic-guidance/index.html.This report focuses on recommendations for the use of vaccines for the prevention and control of seasonal influenza during the 2020-21 season in the United States. A brief summary of the recommendations and a link to the most recent Background Document containing additional information are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html. These recommendations apply to U.S.-licensed influenza vaccines used within Food and Drug Administration (FDA)-licensed indications. Updates and other information are available from CDC's influenza website (https://www.cdc.gov/flu). Vaccination and health care providers should check this site periodically for additional information.


Subject(s)
Influenza Vaccines/therapeutic use , Influenza, Human/prevention & control , Adolescent , Adult , Advisory Committees , Aged , Centers for Disease Control and Prevention, U.S. , Child , Child, Preschool , Female , Humans , Immunization Schedule , Infant , Influenza A Virus, H1N1 Subtype , Influenza A Virus, H3N2 Subtype , Influenza B virus , Influenza Vaccines/adverse effects , Influenza, Human/epidemiology , Male , Middle Aged , Pregnancy , Randomized Controlled Trials as Topic , Risk Assessment , Seasons , United States/epidemiology , Vaccines, Attenuated/therapeutic use , Young Adult
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