Transcript Vaccines in
Personal Controls Personal Controls • Today – Vaccines/Immunization – Hand Hygiene – PPE??? • Later – Antimicrobial Use and Resistance Immunization/Vaccines Vaccine Strategies: Routine Vaccination • • • • • • • • • • • • Measles Mumps Rubella (german measles) Polio Pertussis (whooping cough) Diphtheria Tetanus Haemophilus influenzae type b (Hib) Hepatitis B Varicella (chickenpox) Pneumococcal disease Influenza (flu) Vaccine Strategies: Ring Vaccination Principles of Vaccination Immunity • Self vs. non-self • Protection from infectious disease • Usually indicated by the presence of antibody • Very specific to a single antigen Principles of Vaccination Active Immunity • Protection produced by the person's own immune system • Usually permanent Passive Immunity • Protection transferred from another person or animal as antibody • Temporary protection that wanes with time Principles of Vaccination Antigen • A live or inactivated substance (e.g., protein, polysaccharide) capable of producing an immune response Antibody • Protein molecules (immunoglobulin) produced by B lymphocytes to help eliminate an antigen Passive Immunity • Transfer of antibody produced by one human or other animal to another • Transplacental most important source in infancy • Temporary protection Sources of Passive Immunity • Almost all blood or blood products • Homologous pooled human antibody (immune globulin) • Homologous human hyperimmune globulin • Heterologous hyperimmune serum (antitoxin) Antibody for Prevention of RSV • RSV-IGIV – Human hyperimmune globulin – Contains other antibodies • Palivizumab (Synagis) – Monoclonal – Contains only RSV antibody Vaccination • Active immunity produced by vaccine • Immunity and immunologic memory similar to natural infection but without risk of disease The more similar a vaccine is to the natural disease, the better the immune response to the vaccine. Classification of Vaccines • Live attenuated – viral – bacterial • Inactivated – Whole • Virus • Bacteria – Fraction • Protein-based (sub-unit or toxoid) • Polysaccharide-based (pure or conjugated) Live Attenuated Vaccines • Attenuated (weakened) form of the "wild" virus or bacteria • Must replicate to be effective • Immune response similar to natural infection • Usually effective with one dose* *except those administered orally Live Attenuated Vaccines • Severe reactions possible • Interference from circulating antibody • Unstable Live Attenuated Vaccines • Viral measles, mumps, rubella, vaccinia, varicella, yellow fever, influenza, (oral polio) (rotavirus) • Bacterial BCG, oral typhoid Vaccines in (parenthesis) are not available in the United States. Inactivated Vaccines • • • • • • Cannot replicate Minimal interference from circulating antibody Generally not as effective as live vaccines Generally require 3-5 doses Immune response mostly humoral Antibody titer diminishes with time Inactivated Vaccines Whole cell vaccines • Viral polio, hepatitis A, rabies (influenza) • Bacterial (pertussis) (typhoid) (cholera) (plague) Fractional vaccines • Subunit hepatitis B, influenza, acellular pertussis, (Lyme) Vaccines in (parenthesis) are not available in the United States. • Toxoid diphtheria, tetanus Pure Polysaccharide Vaccines • Not consistently immunogenic in children <2 years of age • No booster response • Antibody with less functional activity • Immunogenicity improved by conjugation Polysaccharide Conjugate Vaccines • Stimulates T-dependent immunity • Enhanced antibody production, especially in young children • Repeat doses elicit booster response • Antibody is biologically active in vitro Polysaccharide Vaccines Pure polysaccharide • pneumococcal • meningococcal • Salmonella Typhi (Vi) Conjugate polysaccharide • Haemophilus influenzae type b • pneumococcal Vaccine Additives • Tiny amounts of three types of substances may be added to vaccines. • Preservatives keep bacteria or fungus from growing, which could otherwise give vaccine recipients serious infections. • Stabilizers help the vaccine keep its correct chemical composition even if conditions (such as temperature) change dramatically. • Adjuvants boost the vaccine’s ability to provide an immune response. • All additives are within the safety margins established by federal agencies. • Some additives can cause redness and soreness on the skin where the vaccination has been given. Adjuvants Stabilizers Preservatives Childhood Vaccination Concerns • The use of thimerosal (ethylmercury) as an additive in vaccines • An unsubstantiated link between the MMR vaccine (combination for measles, mumps, and rubella) and autism • The necessity of vaccinating children against hepatitis B • Pneumococcal conjugate (a new vaccine to protect against meningitis) • The relative danger of varicella (chickenpox) Thimerosal • Thimerosal is preservative which contains a form of mercury (ethylmercury). • Thimerosal was used in very small amounts for over 50 years as a preservative in some vaccines. • Thimerosal was originally added to multi-dose vials of vaccines. It protected these vaccines from bacterial contamination. • Mercury can have toxic effects in large amounts. However, there’s no evidence that the tiny amounts of thimerosal in vaccines has ever caused problems for infants receiving these vaccines. • Today, with the exception of some flu vaccines, none of the vaccines used in the U.S. to protect preschool-aged children against 12 infectious diseases contain thimerosal as a preservative. MMR Vaccine: Is It Really a Factor in Autism? • Some parents and others have expressed concern about a possible link between the MMR (measles, mumps, rubella) vaccine and the development of autism in children because: – MMR vaccine is first given at age 12 to 15 months. – The first signs of autism (poor social interaction and speech, repetitive behaviors) often appear between 12 to 18 months of age. MMR vaccine first given Birth 0 months First signs of autism 12 months 15 months Independent Studies Have Found No Link between Autism and MMR. • • • • A United States study by Dr. Loring Dales showed that the number of autism cases in young children increased even when the number of MMR vaccines decreased over the same time period! A British study by Dr. Brent Taylor showed that the number of diagnosed autism cases did not increase after the MMR vaccine was introduced in 1988. If a link between the MMR vaccine and autism did exist, the number of autism cases would increase or decrease over time as the number of children immunized with MMR increased or decreased over the same time. No study has shown this trend. Additional well-designed studies in the United States and in Europe have found no association between the MMR vaccination and autism. Varicella (Chickenpox): Not a “Harmless” Childhood Disease • Many people believe chickenpox is a harmless illness. • In 1999, an average of one child a week died in the United States from complications of chickenpox. • These complications include encephalitis, a brain infection; severe staph and strep secondary infections (flesh-eating strep and toxic shock syndrome); hepatitis; and pneumonia. Vaccination Works! Measles 1958-1962: Over a half a million cases of measles are reported each year. 432 measles-related deaths occur on average each year. Measles vaccine is licensed. By 2000, only 81 cases are reported in all of the U.S.! 1958 1962 1963 2000 Vaccination Works! Hib Meningitis • Consider the history of Hib meningitis. • Haemophilus influenzae type b (Hib) disease usually strikes children under 5 years of age. • Hib can cause blood poisoning or meningitis. 1985 and before: An estimated 20,000 children develop Hib every year, with 600 deaths. 1985 and before First Hib vaccine is licensed. Fewer than 10 Hib deaths are reported. 1985 1998 Vaccination Works! Polio 1951-1954: Paralytic polio strikes nearly 20,000 Americans every year, killing nearly 1,900. First polio vaccine is licensed. 1951 1954 1955 Today there are no reports of polio in the United States, but the disease still exists in some parts of the world. TODAY Comparison of Maximum and Current Reported Morbidity, Vaccine-Preventable Diseases and Vaccine Adverse Events, United States Disease Pre-vaccine Era* Diphtheria 31,054 Measles 390,852 Mumps 21,342 Pertussis 117,998 Polio (wild) 4,953 Rubella 9,941 Cong. Rubella Synd. 19,177 Tetanus 1,314 Invasive Hib Disease** 24,856 Total 566,706 Vaccine Adverse Events * + ^ ** 0 2000 % change 1 86 338 -99 -99 -99 7,867 -93 0 176 9 35 112 -100 -98 -99 -97 -99 8,624 -98 13,497 ^ +++ Maximum cases reported in pre-vaccine era Estimated because no national reporting existed in the prevaccine era Adverse events after vaccines against diseases shown on Table = 5,296 Invasive type b and unknown serotype Antisepsis/Hand Hygiene Definitions • Hand hygiene – Performing handwashing, antiseptic handwash, alcoholbased handrub, surgical hand hygiene/antisepsis • Handwashing – Washing hands with plain soap and water • Antiseptic handwash – Washing hands with water and soap or other detergents containing an antiseptic agent • Alcohol-based handrub – Rubbing hands with an alcohol-containing preparation • Surgical hand hygiene/antisepsis – Handwashing or using an alcohol-based handrub before operations by surgical personnel Guideline for Hand Hygiene in Health-care Settings. MMWR 2002; vol. 51, no. RR-16. Preparations for hand Hygiene • Plain soap (detergent-based containing esterified fatty acids and NaOH or KOH) • Alcohols (isopropanol, n-propanol, ethanol or combo) – 60-95% alcohol most effective (70% w/w ideal) – Mechanism is denaturing of proteins, proteins not denatured as easily in absence of water • Chlorhexidine (chlorhexidine gluconate) – Mechanism is attachment and disruption of cytoplasmic membrane resulting in precipitation of cellular contents • Chloroxylenol (PCMX, halogenated phenolic) – Mechanism is inactivation of bacterial enzymes and alteration of cell walls Preparations for hand Hygiene • Hexachlorophene (bisphenol compound) – Mechanism is inactivation of essential enzyme activity in microbes • Iodine and Iodofors – Mechanism is impaired protein synthesis and alteration of cell membranes • QACs (quaternary ammonium compounds) – Mechanism is binding to cytoplasmic membrane causing leakage of low MW constituents • Triclosan – Mechanism is interference with synthesis of RNA, fatty acids, and proteins So Why All the Fuss About Hand Hygiene? Most common mode of transmission of pathogens is via hands! Infections acquired in healthcare Spread of antimicrobial resistance Hand Hygiene: The Data Since 1977, 7 of 8 prospective studies have shown that improvement in hand hygiene significantly decreases infection rates Clin Infect Dis 1999;29:1287-94 Efficacy of Hand Hygiene Preparations in Killing Bacteria Good Better Plain Soap Antimicrobial soap Best Alcohol-based handrub Studies Comparing Relative Efficacy of Plain Soap or Antimicrobial Soap vs Alcohol-Based Antiseptics in Reducing Counts on Hands • Alcohol more effective than plain soap (17 studies) • In all but two trials (15/17), alcohol-based solutions reduced bacterial counts on hands to a greater extent than washing with soaps or detergents containing povidone-iodine, 4% CHG, or triclosan Bacterial Reduction Ability of Hand Hygiene Agents to Reduce Bacteria on Hands % 99.9 Time After Disinfection log 0 60 180 minutes 3.0 99.0 2.0 90.0 1.0 0.0 0.0 Alcohol-based handrub (70% Isopropanol) Antimicrobial soap (4% Chlorhexidine) Baseline Plain soap Adapted from: Hosp Epidemiol Infect Control, 2nd Edition, 1999. Alcohol-Based Hand Cleansers Soap and Water Alcohol Solution # of HCWs n = 43 n = 43 Reduction in CFUs 50% 88% Non-medicated soap used; alcohol was mixture of n-propanol and isopropanol; hands contaminated under clinical conditions Am J Infect Control 1999; 27:258-61 What about viruses? • Lipophillic (i.e. enveloped) viruses are significantly reduced • Non-enveloped?? – Reduced but not eliminated – Long contact times required Alcohol based hand scrubs on NV • Studies rely on surrogates rather than NV – Typically FCV or CaCV, but recently MNV • Mori et al., 2006 – 99% of FCV removed by hand washing (compared to rinsing); similar removals with other hand scrubs • Malik et al., 2006 – Isopropanol (40-60%) and ethanol (70-90%) reduced virus on hands by 99% (range 1-3 log10) in one minute (no significant improvement in inactivation up to 10 minutes) • Duizer et al., 2004 – Reduction of FCV and CaCV in 70% ETOH at room temperature • 1 log10 after 1 minute • 2.5-3 log10 after 30 minutes Alcohol based hand scrubs on NV • Kampf et al., 2005 Alcohol based hand scrubs on NV • Gehrke et al., 2004 Alcohol based hand scrubs on NV • Gehrke et al., 2004 cont. Historical Perspective • As early as 1822, a french pharmacist Labbarraque reported on the use of chlorides of lime or soda for cleansing hands • In 1842 Holmes concluded puerperal fever spread by hands of health care workers • In 1846, Semmelweis observed that women who had babies delivered by doctors coming from autopsies had a higher mortality rate than women whose babies were delivered by midwives, postulated puerperal fever caused by cadavarous particles • In 1847 he insisted physicians and students clean their hands with a chlorine solution, mortality rates dropped, first evidence disinfection more effective than soap and water alone Ignaz Semmelweis, 1815-1865 – First Clinic: Doctors and medical students – Second Clinic: Midwives 16 Maternal mortality, 1842 • 1840’s: General Hospital of Vienna • Divided into two clinics, alternating admissions every 24 hours: 14 12 10 8 6 4 2 0 First Clinic Second Clinic The Intervention: Hand scrub with chlorinated lime solution Hand hygiene basin at the Lying-In Women’s Hospital in Vienna, 1847. Hand Hygiene: Not a New Concept Maternal Mortality due to Postpartum Infection General Hospital, Vienna, Austria, 1841-1850 Semmelweis’ Hand Hygiene Intervention Maternal Mortality (%) 18 16 14 12 10 8 6 4 2 0 1841 1842 1843 1844 1845 MDs 1946 1847 1848 1849 1850 Midwives ~ Hand antisepsis reduces the frequency of patient infections ~ Adapted from: Hosp Epidemiol Infect Control, 2nd Edition, 1999. Modern History • 1961 US Public Health Service produced training film for Health Care Workers (HCW) recommending 1-2 minute hand scrub with soap and water • 1975 and 1985 formal handwashing guidelines published by CDC recommended washing with soap and water between majority of patients and with antimicrobial soap after invasive procedure • 1988 and 1995 guidelines for hand washing and antisepsis published by APIC, similar to CDC but 1995 document gave consideration to alcohol hand rubs • 1996 HICPAC recommended antimicrobial soap or waterless antiseptic agent be used upon leaving rooms of patients infected with drug resistant organisms • Though adopted by majority of hospitals, adherence by HCWs still low Current Recommendations • Joint task force HICPAC/APIC/SHEA/IDSA • When hands visibly soiled use soap and water, if not visibly soiled use alcohol based rub or wash with soap and water • Decontaminate hands with alcohol rub Before: – Direct contact w/patients – Gloving – When moving from contaminated body area to clean area After: – Contact with patient – Contact with inanimate objects – Removing gloves • Wash with soap and water before eating or after using restroom Recommended Hand Hygiene Technique • Handrubs – Apply to palm of one hand, rub hands together covering all surfaces until dry – Volume: based on manufacturer • Handwashing – Wet hands with water, apply soap, rub hands together for at least 15 seconds – Rinse and dry with disposable towel – Use towel to turn off faucet Guideline for Hand Hygiene in Health-care Settings. MMWR 2002; vol. 51, no. RR-16. Hand Hygiene Practices in Healthcare • Hand hygiene has been reported to average 40% (34 studies) – Inaccessibility of hand hygiene supplies – Skin irritation from hand hygiene agents – Inadequate time for hand hygiene – Interference with patient care – Lack of knowledge of the guidelines – Lack of information on the importance of hand hygiene Hand Hygiene Adherence in Hospitals Year of Study Adherence Rate Hospital Area 1994 (1) 29% General and ICU 1995 (2) 41% General 1996 (3) 41% ICU 1998 (4) 30% General 2000 (5) 48% General 1. Gould D, J Hosp Infect 1994;28:15-30. 2. Larson E, J Hosp Infect 1995;30:88106. 3. Slaughter S, Ann Intern Med 1996;3:360-365. 4. Watanakunakorn C, Infect Control Hosp Epidemiol 1998;19:858-860. 5. Pittet D, Lancet 2000:356;1307-1312. Hand Hygiene Practices in Healthcare • Observational studies revealed that duration averages from 6.6 to 21 sec, and in 10/14 studies HW <15 sec, and in 8/14 studies HW < 10 sec • HCWs also fail to wash all surfaces of their hands and fingers effectively Areas Most Frequently Missed HAHS © 1999 Many personnel don’t realize when they have germs on their hands Nurses, doctors and other healthcare workers can get 100s or 1000s of bacteria on their hands by doing simple tasks, like •pulling patients up in bed •taking a blood pressure or pulse •touching a patient’s hand •rolling patients over in bed •touching the patient’s gown or bed sheets •touching equipment like bedside rails, over-bed tables, IV pumps How can this happen? Culture plate showing growth of bacteria 24 hours after a nurse placed her hand on the plate Hand Hygiene and “Clean Procedures” • Personnel contaminate hands by performing “clean procedures” • Nurses contaminate hands with 100-1000 CFU during such “clean” activities as lifting patients, taking the patient’s pulse, blood pressure, or oral temperature, or touching the patient’s hand, shoulder, or groin. Colonized or Infected: What is the Difference? • People who carry bacteria without evidence of infection (fever, increased white blood cell count) are colonized • If an infection develops, it is usually from bacteria that colonize patients • Bacteria that colonize patients can be transmitted from one patient to another by the hands of healthcare workers ~ Bacteria can be transmitted even if the patient is not infected ~ The Iceberg Effect Infected Colonized Recovery of VRE from Hands and Environmental Surfaces Up to 41% of healthcare worker’s hands sampled (after patient care and before hand hygiene) were positive for VRE1 VRE were recovered from a number of environmental surfaces in patient rooms VRE survived on a countertop for up to 7 days2 1 Hayden MK, Clin Infect Diseases 2000;31:1058-1065. 2 Noskin G, Infect Control and Hosp Epidemi 1995;16:577-581. The Inanimate Environment Can Facilitate Transmission X represents VRE culture positive sites ~ Contaminated surfaces increase cross-transmission ~ Abstract: The Risk of Hand and Glove Contamination after Contact with a VRE (+) Patient Environment. Hayden M, ICAAC, 2001, Chicago, IL. Skin Prep • Chlorhexidine 2% is more effective than povidone iodine (Betadine) because it dries quickly and has longer residual action • If you must use Betadine – Allow Betadine to dry completely (at least 2 minutes) – Do not blow on, fan, or blot the site to make it dry faster!