The Efficacy of Influenza Vaccination in Elderly Individuals: A Randomized Double-blind Placebo-Controlled Trial
TL;DR: In the elderly, influenza vaccination may halve the incidence of serological and clinical influenza (in periods of antigenic drift), which is less pronounced for self-reported influenza.
Abstract: Objective. —To determine the efficacy of influenza vaccination in elderly people. Design. —Randomized double-blind placebo-controlled trial. Setting. —Fifteen family practices in the Netherlands during influenza season 1991-1992. Participants. —A total of 1838 subjects aged 60 years or older, not known as belonging to those high-risk groups in which vaccination was previously given. Intervention. —Purified split-virion vaccine containing A/Singapore/6/86(H1N1), A/Beijing/353/89(H3N2), B/Beijing/1/87, and B/Panama/45/90 (n=927) or intramuscular placebo containing physiological saline solution (n=911). Main Outcome Measures. —Patients presenting with influenzalike illness up to 5 months after vaccination; self-reported influenza in postal questionnaires 10 weeks and 5 months after vaccination; serological influenza (fourfold increase of antibody titer between 3 weeks and 5 months after vaccination). Results. —The incidence of serological influenza was 4% in the vaccine group and 9% in the placebo group (relative risk [RR], 0.50; 95% confidence interval [CI], 0.35 to 0.61). The incidences of clinical influenza were 2% and 3%, respectively (RR, 0.53; 95% CI, 0.39 to 0.73). The effect was strongest for the combination of serological and clinical influenza (RR, 0.42; 95% CI, 0.23 to 0.74). The effect was less pronounced for self-reported influenza. Conclusion. —In the elderly, influenza vaccination may halve the incidence of serological and clinical influenza (in periods of antigenic drift). (JAMA. 1994;272:1661-1665)
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TL;DR: This report updates the 2000 recommendations by the Advisory Committee on Immunization Practices on the use of influenza vaccine and antiviral agents with new or updated information regarding the cost-effectiveness of influenza vaccination and the 2001-2002 trivalent vaccine virus strains.
Abstract: This report updates the 2002 recommendations by the Advisory Committee on Immunization Practices (ACIP) on the use of influenza vaccine and antiviral agents (CDC. Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2002;51 [No. RR-3]:1-31). The 2003 recommendations include new or updated information regarding 1) the timing of influenza vaccination by age and risk group; 2) influenza vaccine for children aged 6-23 months; 3) the 2003-2004 trivalent inactivated vaccine virus strains: A/Moscow/10/99 (H3N2)-like, A/New Caledonia/20/99 (H1N1)-like, and B/Hong Kong/330/2001-like antigens (for the A/Moscow/10/99 [H3N2]-like antigen, manufacturers will use the antigenically equivalent A/Panama/2007/99 [H3N2] virus, and for the B/Hong Kong/330/2001-like antigen, manufacturers will use either B/Hong Kong/330/2001 or the antigenically equivalent B/Hong Kong/1434/2002); 4) availability of certain influenza vaccine doses with reduced thimerosal content, including single 0.25 mL-dose syringes; and 5) manufacturers of influenza vaccine for the U.S. market. Although the optimal time to vaccinate against influenza is October and November, vaccination in December and later continues to be strongly recommended A link to this report and other information regarding influenza can be accessed at http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm.
5,334 citations
Journal Article•
TL;DR: This report updates the 2008 recommendations by CDC's Advisory Committee on Immunization Practices regarding the use of influenza vaccine for the prevention and control of seasonal influenza and includes a summary of safety data for U.S. licensed influenza vaccines.
Abstract: This report updates the 2009 recommendations by CDC's Advisory Committee on Immunization Practices (ACIP) regarding the use of influenza vaccine for the prevention and control of influenza (CDC. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2009;58[No. RR-8] and CDC. Use of influenza A (H1N1) 2009 monovalent vaccine---recommendations of the Advisory Committee on Immunization Practices [ACIP], 2009. MMWR 2009;58:[No. RR-10]). The 2010 influenza recommendations include new and updated information. Highlights of the 2010 recommendations include 1) a recommendation that annual vaccination be administered to all persons aged >or=6 months for the 2010-11 influenza season; 2) a recommendation that children aged 6 months--8 years whose vaccination status is unknown or who have never received seasonal influenza vaccine before (or who received seasonal vaccine for the first time in 2009-10 but received only 1 dose in their first year of vaccination) as well as children who did not receive at least 1 dose of an influenza A (H1N1) 2009 monovalent vaccine regardless of previous influenza vaccine history should receive 2 doses of a 2010-11 seasonal influenza vaccine (minimum interval: 4 weeks) during the 2010--11 season; 3) a recommendation that vaccines containing the 2010-11 trivalent vaccine virus strains A/California/7/2009 (H1N1)-like (the same strain as was used for 2009 H1N1 monovalent vaccines), A/Perth/16/2009 (H3N2)-like, and B/Brisbane/60/2008-like antigens be used; 4) information about Fluzone High-Dose, a newly approved vaccine for persons aged >or=65 years; and 5) information about other standard-dose newly approved influenza vaccines and previously approved vaccines with expanded age indications. Vaccination efforts should begin as soon as the 2010-11 seasonal influenza vaccine is available and continue through the influenza season. These recommendations also include a summary of safety data for U.S.-licensed influenza vaccines. These recommendations and other information are available at CDC's influenza website (http://www.cdc.gov/flu); any updates or supplements that might be required during the 2010-11 influenza season also will be available at this website. Recommendations for influenza diagnosis and antiviral use will be published before the start of the 2010-11 influenza season. Vaccination and health-care providers should be alert to announcements of recommendation updates and should check the CDC influenza website periodically for additional information.
1,659 citations
Cites background from "The Efficacy of Influenza Vaccinati..."
...vaccine efficacy of 58% (CI = 26%--77%) against laboratory-confirmed influenza illness during a season when the vaccine strains were considered to be well-matched to circulating strains (159)....
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TL;DR: Influenza vaccines can provide moderate protection against virologically confirmed influenza, but such protection is greatly reduced or absent in some seasons.
Abstract: Summary Background No published meta-analyses have assessed efficacy and effectiveness of licensed influenza vaccines in the USA with sensitive and highly specific diagnostic tests to confirm influenza. Methods We searched Medline for randomised controlled trials assessing a relative reduction in influenza risk of all circulating influenza viruses during individual seasons after vaccination (efficacy) and observational studies meeting inclusion criteria (effectiveness). Eligible articles were published between Jan 1, 1967, and Feb 15, 2011, and used RT-PCR or culture for confirmation of influenza. We excluded some studies on the basis of study design and vaccine characteristics. We estimated random-effects pooled efficacy for trivalent inactivated vaccine (TIV) and live attenuated influenza vaccine (LAIV) when data were available for statistical analysis (eg, at least three studies that assessed comparable age groups). Findings We screened 5707 articles and identified 31 eligible studies (17 randomised controlled trials and 14 observational studies). Efficacy of TIV was shown in eight (67%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 59% [95% CI 51–67] in adults aged 18–65 years). No such trials met inclusion criteria for children aged 2–17 years or adults aged 65 years or older. Efficacy of LAIV was shown in nine (75%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 83% [69–91]) in children aged 6 months to 7 years. No such trials met inclusion criteria for children aged 8–17 years. Vaccine effectiveness was variable for seasonal influenza: six (35%) of 17 analyses in nine studies showed significant protection against medically attended influenza in the outpatient or inpatient setting. Median monovalent pandemic H1N1 vaccine effectiveness in five observational studies was 69% (range 60–93). Interpretation Influenza vaccines can provide moderate protection against virologically confirmed influenza, but such protection is greatly reduced or absent in some seasons. Evidence for protection in adults aged 65 years or older is lacking. LAIVs consistently show highest efficacy in young children (aged 6 months to 7 years). New vaccines with improved clinical efficacy and effectiveness are needed to further reduce influenza-related morbidity and mortality. Funding Alfred P Sloan Foundation.
1,579 citations
TL;DR: The peer-reviewed and preprint literature pertaining to cardiovascular considerations related to COVID-19 are reviewed to highlight gaps in knowledge that require further study pertinent to patients, health care workers, and health systems.
1,484 citations
Cites background from "The Efficacy of Influenza Vaccinati..."
...of age on the immune system is exemplified by low p rotective titers among 50% of adults older than 65 who receive the influenza vaccine (30,31)....
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TL;DR: This report updates the 2017–18 recommendations of the Advisory Committee on Immunization Practices regarding the use of seasonal influenza vaccines in the United States and focuses on the recommendations for use of vaccines for the prevention and control of influenza during the 2018–19 season.
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.
1,388 citations
References
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TL;DR: In this article, the authors present an overview of the main issues in epidemiology research and propose a method for controlling extraneous factors in the context of epidemiological studies, using Logistic Regression with Interaction, Effect Modification, and synergy.
Abstract: Key Issues in Epidemiologic Research: An Overview. OBJECTIVES AND METHODS OR EPIDEMIOLOGIC RESEARCH. Fundamentals of Epidemiologic Research. Types of Epidemiologic Research. Design Options in Observational Studies. Typology of Observational Study Designs. Measures of Disease Frequency: Incidence. Other Measures of Disease Frequency. Measures of Association. Measures of Potential Impact and Summary of the Measures. VALIDITY OF EPIDEMIOLOGIC RESEARCH. Validity: General Considerations. Selection Bias. Information Bias. Confounding. Confounding Involving Several Risk Factors. PRINCIPLES AND PROCEDURES OF EPIDEMIOLOGIC ANALYSIS. Statistical Inferences About Effect Measures: Simple Analysis. Overview of Options for Control of Extraneous Factors. Stratified Analysis. Matching in Epidemiologic Studies. Interaction, Effect Modification, and Synergism. Modeling: Theoretical Considerations. Modeling: Analysis Strategy. Applications of Modeling with No Interaction. Applications of Logistic Regression with Interaction, Using Unconditional ML Estimation. Applications of Modeling: Conditional Likelihood Estimation. Appendices. Index.
3,179 citations
Book•
01 Jan 1982
TL;DR: In this article, the authors present an overview of the main issues in epidemiology research and propose a method for controlling extraneous factors in the context of epidemiological studies, using Logistic Regression with Interaction, Effect Modification, and synergy.
Abstract: Key Issues in Epidemiologic Research: An Overview. OBJECTIVES AND METHODS OR EPIDEMIOLOGIC RESEARCH. Fundamentals of Epidemiologic Research. Types of Epidemiologic Research. Design Options in Observational Studies. Typology of Observational Study Designs. Measures of Disease Frequency: Incidence. Other Measures of Disease Frequency. Measures of Association. Measures of Potential Impact and Summary of the Measures. VALIDITY OF EPIDEMIOLOGIC RESEARCH. Validity: General Considerations. Selection Bias. Information Bias. Confounding. Confounding Involving Several Risk Factors. PRINCIPLES AND PROCEDURES OF EPIDEMIOLOGIC ANALYSIS. Statistical Inferences About Effect Measures: Simple Analysis. Overview of Options for Control of Extraneous Factors. Stratified Analysis. Matching in Epidemiologic Studies. Interaction, Effect Modification, and Synergism. Modeling: Theoretical Considerations. Modeling: Analysis Strategy. Applications of Modeling with No Interaction. Applications of Logistic Regression with Interaction, Using Unconditional ML Estimation. Applications of Modeling: Conditional Likelihood Estimation. Appendices. Index.
2,899 citations
TL;DR: It is suggested that influenza vaccine can reduce the incidence and severity of influenza virus infections among the elderly and chronically ill and underscore the importance of vaccination programs for those in nursing homes and in the general community.
Abstract: From December 10, 1982, to March 4, 1983, when influenza A (H3N2) viruses circulated in Michigan, outbreaks of influenza-like illness were identified in seven nursing homes in Genesee County; 272 (27%) of 1,018 residents were affected. Unvaccinated residents were more likely than vaccinated residents to become ill (risk ratio [RR], 2.6; 95% confidence interval [CI], 1.8-3.6) and were subsequently more likely to be hospitalized (RR, 2.4; 95% CI, 1.2-4.8), develop roentgenographically proven pneumonia (RR, 2.9; 95% CI, 1.6-5.3), or die (RR, 5.6; 95% CI, 1.2-9.1). Similar observations were made during investigations in six of the eight remaining nursing homes in Genesee County, in which 57 (12%) of 458 residents became ill sporadically. These findings suggest that influenza vaccine can reduce the incidence and severity of influenza virus infections among the elderly and chronically ill and underscore the importance of vaccination programs for those in nursing homes and in the general community. (JAMA1985;253:1136-1139)
359 citations
TL;DR: The authors study the occurrence of excess morbidity and mortality among subsets of the adult population of a large prepaid group practice during two epidemics of type A influenza to provide a basis for increasing the precision of clinical and public decision-making regarding the prevention of serious consequences of epidemic influenza.
Abstract: The authors studied the occurrence of excess morbidity and mortality among subsets of the adult population (persons over 14 years of age) of a large prepaid group practice during two epidemics of type A influenza (1968-1969 and 1972-1973). The experience from 1970-1971, a nonepidemic years, was used as a reference for estimating excesses. Ambulatory visits for influenza and influenza-related acute respiratory disease increased by 5-7 visits per 100 persons (30-50% excess) and pneumonia and influenza (P&I) hospitalization rates increased by 79-86 per 100,000 (140-150% excess) over the rates in the nonepidemic period. There were 11-13 excess deaths per 100,000 population, most of which involved persons over 65 years of age. Excess rates of ambulatory visits were similar for all adult age groups. Excess rates of persons hospitalized with P&I ranged from 23-25 per 100,000 among non-high risk persons aged 15-44 years to 150-172 per 100,000 among persons over age 65 years without underlying "high risk" conditions and 476-636 per 100,000 persons over 65 with underlying "high risk" conditions. These data provide a basis for increasing the precision of clinical and public decision-making regarding the prevention of serious consequences of epidemic influenza.
359 citations
TL;DR: It is suggested that annual revaccination with inactivated influenza-A vaccine confers no long-term advantage.
296 citations