Communicable Dis - Test 1

Public Health 1.0
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-Modernizing goals and missions
-Launched by HHS in 2016 because of silos
-Commitment on health disparities
-Sharper focus on all the factors that affect health
-Core rec: PH leaders as chief health strategists, PH dept engage in cross-sector collaboration, accreditation is important, comfortable with new data sources, and explore new funding models
-New web-based data collection and surveillance
Michigan RulesHome Rule: protection of PH is a primary purpose of local gov -Decentralized -45 HD -$56 billion and half goes to HHS. $26 billion HHS with 3% for PH. About $1.4 billionCentralized GovLocal health units are primarily led by employees of the state and the state retains authority over most fiscal decisionsShared GovLocal health units may be led by employees of the state or of local gov. If they are led by state employees, then local gov has authority to make fiscal decisions and/or issue PH ordersMixed GovSome local health units are led by employees of the state and some are led by employees of the local gov. No one arrangement predominates in the state.Decentralized GovLocal health units are primarily led by employees of local gov and the local govs retain authority over most fiscal decisionsPurpose of Surveillance Systems-Determine baseline rates of disease -Describe extent of a problem -Identify and describe populations at risk -Detect epidemics and outbreaks -Monitor changes in disease -Assess interventions and control strategies -Aid in resource allocationHistory of Surveillance 1850 1893 1901 1949 1952 1999 2002-1850: Lemuel Shattruck's MA Sanitary Commission, national surveillance -1893: MI require reporting dis -1901: all states dis reporting -1949: National office vital stats -1952: publication of MMWR -1999: electronic disease surv system -2002: bioterrorism fundingSurveillance steps1) Select problem 2) Define problem 3) Collect data 4) Analyze and interpret data 5) Disseminate data 6) Evaluate usefulness and qualityPublic Health Importance-Magnitude: incidence, prev -Severity: mort rate -Cost -Preventability -Communicability -Political/public pressureCase definition (Confirmed cases, probable, suspected)-Person, place, time, clinical -Confirmed cases: lab -Probable cases: have characteristic clinical features but lack lab info -Suspected cases: have some of the clinical featuresCase Definition Sensitivity-Sensitive: broad, hope of capturing most or all true cases at expense of including other illnesses -Specific: narrow and will likely include only true cases at expense of excluding mild or atypical casesBurden of Illness PyramidSurveillance Evaluation FrameworkEngage stakeholders -> described surv system -> focus the eval design -> gather evidence -> justify and state conclusions, make rec -> ensure use of eval findingsLow PPV vs High PPV-Low: many detected cases are not true cases, generally less specific case definition, lower prev -High: most detected cases are true, generally more specific case definition,higher prevPassive Surveillance (Reporting)-Providers required to report individual cases. Routine reporting. -PRO: less costly, standardized, simple -CON: limited variability and often incomplete, relay on busy staff -> underreporting, possibly biased, lack of representativeness in casesActive Surveillance (Searching)-Regular contact with reporting sources to solicit data -Much more resource intensive -Used for conditions of importance - special reporting -PRO: more complete, useful in outbreak -CON: more costly/resource intensive, not representative Ex) MRSA screeningSentinel Surveillance-Select providers recruited and report on predetermined basis -Units have a high probability for seeing disease -Well-trained staff, lab facilities. Only a limited network of selected sites. -Reasonably accurate and moderately resource intensive -Can be active or passive (monitoring health events, reporting by hospitals, longitudinal cohorts, registries) -PRO: when national surv systems are not available, large surveys too costly, condition prevalence is high -CON: not as effective for rare diseasesSyndromic-Continuously monitor existing health data -Categorize symptoms and diagnoses into broad illness syndromes -Surveillance by specific syndromes to detect, monitor, and characterize unusual activity for further investigation and response -Looking for symptoms without diagnosisState Notifiable Disease List-Passive -Differs by state and changes over time -Legal req to report to PH authorities is vested in state -Providers, hospitals, and labs are req to report to LHD. LHD is responsible for case investigation and actions, forwards to stateClinical ClassificationAcute vs chronic Latent vs active Asymptomatic vs symptomatic Local, systemic, invasive Primary vs secondary Symptom-based (febrile, respiratory, diarrheal, gastrointestinal)Biological Characteristics-Virulence: severity of the disease after the infection occurs (case fatality rate: prop of cases that result in death) -Infectivity: ability of an agent to cause infection in a susceptible host (Secondary attack rate: proportion that develop dis after exp to primary case within incubation period)Calculate Secondary Attack Rate Consider an outbreak of shigellosis in which 18 persons in 18 households all become ill. If the population of the community was 1,000 then the overall attack rate was ______. One incubation late, 17 persons in the same households as these primary cases developed shigellosis. If the households included 86 persons, calculate the secondary attack rate.AR = 18/1,000 x 100% = 0.018 1.8% SAR = 17/(86-18) x 100 = 25ImmunogenicityAbility of an organism to produce an immune response that can provide protection against reinfectionInapparent InfectionPresence of infection in a host without recognizable clinical signs or symptoms; only identifiable by lab (subclinical, occult, asymptomatic)Carrier StateA host that harbors an infectious agent without discernible clinical disease and serves as a potential source of infection; can occur before or after developmental of clinical diseaseClassification by Occurrence-Sporadic: dis infreq -Endemic: Usual, expected occurrence of dis within a pop -Epidemic: unusual occurrence of diseaseHyperendemicConstantly present at high incidence/prevalenceHoloendemicHigh level of infection early in life and affecting most of childhood population, such as adult population shows evidence of disease much less commonly than childrenClusterAggregation of cases grouped in place and time that are suspected to be greater than expected, even though the expected number may not be knownClassification by Occurrence 1. 22 cases of legionellosis occurred within 3 weeks among residents of a particular neighborhood (usually ~1 per year) 2. Avg annual incidence was 364 cases of pulmonary TB per 100,000 in one area, compared with national avg of 134 per 100,000 3. Over 20 million people worldwide died from flu in 1918-1919 4. Single case of histoplasmosis diagnosed in community 5. About 60 cases of gonorrhea usually reported in this region per week, slightly less than national average1. epidemic 2. hyperendemic 3. pandemic 4. Sporadic 5. endemicIncubation and latent period-Incubation period: time from initial exposure to onset of clinical symptoms -Latent period: time from initial exposure to start of infectiousness (no infection) -Period of communicability: the period during which an individual is infectious and can spread to other hostsTransmission Classification-Contact: direct (skin, mucous membrane, perinatal) and indirect (fomite, blood) -Food/water-borne: ingestion of contaminated food or water -Airborne: inhalation of contaminated air -Vector-borne: dependent on biology of vector and infectivity of organism -Fecal-oral: ingestion of an infectious agent that comes from feces; can be from person to person or in food/waterDirect Transmission-Direct contact with agent: often through skin-to-skin contact, kissing, sex -Droplet spread: aersols -PerinatalIndirect Transmission-Airborne: carried by dust particles or droplet nuclei -Vehicle-borne: inanimate object (fomite) -Vector-borne: via other organisms that carry infectious agent (mechanical: fly on a burger vs biologic: mosquito)ReservoirHabitat in which the agent normally lives, grows, and multiplies Human, animals, soil, waterChain of Infection-Infectious agent -Source/reservoir: person, animal, environment -Portal of exit: skin, resp tract, blood -Mode of transmission: contact, droplet, airborne, vector -Portal of entry: skin, resp tract, blood, ingestion -Susceptible host: immune status, increased risk by immunosuppressionChain of infection for Shigellosis-Agent = shigella -Source: humans -Exit: pass in stool -Transmission: direct (hand contam) and indirect (fly contam food) -Entry: mouth, ingestion -Host: protective immunity is limitedInterventions at AgentAntimicrobial therapy Cleaning, sterilization Hand hygieneInterventions at SourceEnv cleaning Waste management Water treatment Screening Case findingInterventions at Portal of Exitcover cough Wound care Tubes/drainsInterventions at Mode of Transmissions-Direct: isolation, avoid contact -Vehicle: surface decontam -Vector: vector control -Fecal-oral: hand washing -Airborne: maskInterventions at Portal of EntryBed nets Masks and glovesInterventions at Susceptible HostVaccination Antimicrobials Education Herd immuntiyWhere do vaccines break the chain of infectionhost and primary preventionAdaptive vs Innate ImmunityAdaptive: Humoral (B cell) and cellular (T cell), memory, specific pathogens Innate: nonspecific, lots of pathogensArtifical Passive Immunity-Nonspecific immunoglobulin - humologous (human) pooled antibody IVIG (used for people with certain immunodeficiency, some infections like Hep B) -Specific immunoglobulins - homolgous hyperimmune globulins (Hep B, Rabies, Varicella) -Specific immunoglobulins- hterologous (animal) hyperimmune globulins (botulism) -Monoclonal antibody (produced from single clone of B cells and have antibody only to one antigen)Active Natural = Active artificial = Passive natural = Passive artificialinfection vaccine transplacental / breastmilk immunoglobulins / monoclonal antibodiesIgAFound in mucous, saliva, tears, breast milk. Protects against pathogensIgDPart of the B cell receptor. Activates basophils and mast cellsIgEProtects against parasitic worms. Responsible for allergic reactions.IgGSecreted by plasma cells in the blood. Able to cross the placenta into the fetus. Longer lasting.IgMMay be attached to the surface of a B cell or secreted into the blood. Responsible for early stages of immunity. Acute.Vaccines1) Classical - live attentuated 1) Classical - inactivated (toxin, organism, subunit) 2) Synthetic- recombinant 2) synthetic - DNAT Cell Independent ReponseVaccine - polysaccharide antigen - AG and B cell - 1 to 2 weeks - plasma cells - antigen specific IgG antibodies Young children don't respond consistentlyT Cell Dependent ResponseVaccine -> AG and DC -> activated DC -> AG specific B cell or Vaccine-> ag and naive B cell -> ag specific B cellLive Attenuated-Weakened form of wild type virus or bacteria -Must replicate in host -Can spread beyond host (polio) -Immune response similar to natural infection -Effective with relatively few doses -Long-lasting immunity -Severe rxns possible -Revert to disease -Interference from circulating antibody (maternal antibodies and immuneoglobulin can decrease effectiveness) -Unstable, must maintain cold chainInactivated Vaccines-Cannot replicate -Minimal interference from circulating antibodies -Generally not as effective as live vaccines -3/5 doses -Antibody titer falls over time so needs boostersPolysaccharide VaccinesMay require multiple doses, not as good with memory, more robust. Conjugates make a better immune response.General Vaccine Rules-More similar a vaccine is to the organism the more effective it will be -Live attenuated vaccines may be affected by circulating antibody to the antigen; inactivated vaccines are generally not affected -All vaccines can be administered at the same visit -Increasing interval between doses of a multi-dose vaccine doesn't diminish the effectiveness of the vaccine -Decreasing the interval between doses of a multi-dose vaccine may interfere with antibody response Live > inactivated whole cell > subunity Proteins > polysaccharidesLive Vaccines and circulating antibodiesIf a live injectable vaccine must be given around same time that antibody is given, they must be separated by enough time so that the antibody doesn't interfere with viral replication -If the live vaccine is given first, it is necessary to wait at least 2 weeks -If the interval between the vaccine and antibody is less than 2 weeks, the recipient should be tested for immunity or the vaccine dose should be repeated -This is an issue for injectable live vaccines; not for oral or intranasalEfficacy vs Effectiveness vs ImmunogenicityEfficacy: study is carried out under ideal/controlled conditions. Perfect use. Experimental. Effectiveness: regular use. Observational Immunogenicity: exp or obs, immune respImpact of Vaccines on Pop HealthDirect: individual protection Indirect: protection afforded to nonvaccinated Non-specific (off-target): effects beyond organisms target by the vaccineAmerican College of Immunization Practices (ACIP)Committee within CDC that provides advice and guidance on the effective control of VPDs in the US 3 meetings per year and vaccine recVaccines work better than ever1980: 7 dis and 15,000 antigens 2017: 16 dis and only 173 antigensFundingFeds fund 95% -Vaccines for children 45% -Private sector 50%Best practices for protected populationcoadminister vaccines during same visit administer as early as possible Develop/utilize combination vaccinesImmunization Info Systems-Consolidate patient's vaccination records among multiple providers -Provide vaccination needs assessments -Generate reminder/recall notices -Produce official vaccination records -Provide practice and population based vaccination coverage assessmentsVaccine Nudge-Guide choice through default options -Enable choice -Prompt implementation intentions -Frame info -Provide info -Do nothingState Vaccination Requirements-State and local req for school are est by state -All states have medical exemptions, some also exempt religion -Decrease in waiversVaccine Adverse Event Reporting System (VAERS)CDC and FDA early warning system to detect problems related to vaccines -Strengths: collects national data from all states, accepts reports from anyone, collects info about vaccine, the person vaccinated, and the adverse event, data publicly available, can be used as an early warning system to identify adverse events, can FU with patients to obtain records -Limits: not possible to determine if vaccine caused event, can't calculate how often event occurs, mild events less likely to be reported, rates of reports may increase media, reports often lack detailsVaccine safety datalink project (VSD)CDC with 8 MCO to collect histories allowing assessment of eventsNational Vaccine Injury Compensation Program (NVICP)claim can be filed and program provides financial assistance. No fault - presumption that vaccine causes adverse event if no other medical causes can be found Vaccine court: requires medical theory, logical sequence of events, and no other biologically plausible explanationInterstate Commerce Clause-Gives Congress exclusive authority to regulate interstate and foreign commerce -Basis for the fed gov authority to use quarantine and other health measures -Implies prohibition of state laws and regulations that interfere with or discriminate against interstate commerce -Provides the legal foundation of much of the US gov's reg powerNational Emergencies ActEmpowers the President to activate special powers during a crisis but imposes certain procedural formalities when invoking such powersHomeland Security Act of 2002Grants Secretary of Homeland Security a broad leadership role in planning for and responding to emergenciesStafford ActEst the system for presidential disaster or emergency declaration and triggers financial/ physical assistance through FEMA; the state gov must execute the state's emergency response plan firstFederal Food, Drug, and Cosmetics ActAuthorizes the FDA to regulate the safety of food and cosmetics, and the safety and effectiveness of pharmaceuticals, biologics, and medical devices. The HHS secretary can authorize emergency use of unapproved products or approved products for unapproved usesPublic Health Service Act-Gives US PH Service responsibility for preventing the intro, transmission, and spread of communicable dis from foreign countries into the US -Section 319 authorizes secretary to declare a PH emergency -Section 361 can give power to quarantineLegal Authority of CDCQuarantine Can deny ill persons entry into US Can detain, medically examine, and release persons arriving into US and betw states Large scale quarantine last enforced during Spanish flu 1918Parens PatriaeThe authority of the state to serve as a guardian an individual in need of protection and to intervene against abuse or neglect, on behalf of the peopleCompiled LawsGov signs bill, assign Act number, added to laws -Collection of laws currently in force -Chapters, acts, and sections. Chapters have actsAuthority for EmergenciesImminent Danger Order Emergency Order to Control Epidemic Order to Abate a Nuisance Procedures for Control of Disease Inspection or Investigation Authority Inspection of Investigative Warrant Criminal Prosecution Injunction Warning Notice (for involuntary detention and treatment of individuals) Court Order for Detaining, Transporting, Testing, or Treating Carrier of Infectious DiseaseState, Local, Tribal Isolation and QuarantineStates have police power functions to protect the health, safety, and welfare of persons within their borders. To control the spread of disease within their borders, states have laws to enforce the use of isolation and quarantine. These laws can vary from state to state and can be specific or broad. In some states, local health authorities implement state law. In most states, breaking a quarantine order is a criminal misdemeanor. Tribes also have police power authority to take actions that promote the health, safety, and welfare of their own tribal members. Tribal health authorities may enforce their own isolation and quarantine laws within tribal lands, if such laws exist.PreemptionA higher level of gov (state or fed) eliminates or reduces the authority of a lower level over a given issue Fed law is supremeSources of authority for fed and stateFed: interstate commerce clause State: policy powerJacobson v Massachusetts1905: US Supreme Court upheld the Mass BOH authority to require vaccination against smallpox during a smallpox epidemicZucht v KingSan Antonio, TX enacted an ordinance prohibiting any child from attending a public school or other places of edu without having vaccination for smallpox Zucht was excluded from school due to refusal of a vaccine. Zucht sued stating there was no emergency and against liberty Her claims denied and she appealed to su5 Sources of PH authorityUS and state constitutions, statutes, rules, court opinions, executive ordersHealth OfficerMakes determination of threatPH Decision-making toolSituation (facts, threat) Consequences Likelihood Mitigation (how to address threat) Certainty (action now or later) CommunicationHealth Impact of InterventionsTop down from smallest to largest impact Counseling impact -> clinical interventions -> long-lasting protective interventions (vaccine) -> changing the context to make individuals' default decisions healthy (fluoridation) -> socioeconomic factorsImminent Danger OrdersA public health officer can issue an order to avoid, remove or correct an imminent danger Doesn't require declaration of emergency Powerful, fast, flexibleDeciding to Investigate-Extent of health problem: severity, number of cases, source, mode of transmission, ability to prevent/control -Unusual dis presentation -Change in dis pattern -Availability of health dept staffSteps of an Outbreak Investigation1) Prepare for field work (investigate and manage operational issues) 2) Est existence of an outbreak 3) Verify diagnosis 4) Construct a working case definition (leave out hypothesis) 5) Find cases systematically and record info (line list) 6) Perform descriptive epidemiology (Time: epidemic curve, place: spot maps, person) 7) Develop hypothesis 8) Eval hypothesis epidemiologically (retro cohort: attack rate, Case-control: OR) 9) Refine and re-evaluate hypothesis 10) Compare and reconcile lab or env studies 11) Implement control and prevention measures 12) Initiate and maintain surveillance 13) Communicate findingsExamples of Specific and Sensitive Case DefinitionsSens: A guest or visitor to Town A with acute gastrointestinal illness and symptoms onset on or after Sept 19, 2014 Spec: A guest or visitor of Restaurant A with lab confirmed Salmonella T and symptom onset on or after Sept 19, 2014Epidemic Curve-Shows magnitude of outbreak over time -Shape may provide clues about pattern of spread -Shows where you are in outbreak -Can be used for evaluation of programs -Identifies outliers -Deduce a probably time of exposureSteps of Outbreak Investigation Condensed1) Determine outbreak 2) Develop case definition 3) Gather info and determine hypothesis 4) Test hypothesis 5) Take actionCommon Source Epidemic Pattern and 3 typesGroup of person are all exposed to an infectious agent or a toxin from the same source 1) Point source: exp occurs in a brief period, everybody ill in one incubation period 2) Continuous: exp occurs over a period of days, weeks 3) Intermittent: exp occur on and off over timePropagated Outbreak Epidemic PatternResults from transmission from one person to another, cases occur over more than one incubation periodMixed EpidemicsFeatures of both common-source and propagated epidemic patternsAll Immunizations for Children in MI are required to be reported toMI Care Improvement RegistryThe legal authority for dis surveillance isat the state level (Not fed, not cdc, not lhd)In MI PH is empowered to perform in all areas of the ten essential PH services by theMI PH CodeOperating Divisions of HHSCDC, HRSA, CMS NOT femaEx of an indirect rt of transmissionIngestion of contaminated foodIn attempt to detect norovirus activity in the community, a LHD tracks temporal patterns in weekly and seasonal sales of over-the-counter anti-diarrheal and anti-nausea medications. This is best described as which type of surveillance?Syndromic surveillanceCurrently local and state HD aren't req to report individual cases of norovirus to a national surveillance system. In order to monitor outbreaks, the CDC est a network of 11 SHD that are trained to submit detailed epidemiologic data about outbreaks that occur and to submit clinical specimens for further analysis. This is best described as which type of surveillance?SentinelThis organization is responsible for est standard case definitions for nationally notifiable diseaseCouncil for state and territorial epidemiologistsMost outbreaks are uncovered byclinicians that recognize a trend in the communityIn an outbreak setting in which the population is not well defined and the speed of investigation is important, which study design is preferred?Case-controlA 40-year old mean went to a picnic and enjoyed many foods, including tuna salad. 3 hours after eating, he developed severe nausea, vomiting, diarrhea, and felt miserable. Some of his friends who were also at the picnic had similar symptoms. He felt better the next day. Which mechanism of disease is most likely?Disease caused by a preformed toxin from bacteriaAn elderly man who is undergoing chemotherapy for cancer is admitted to the hospital with fever, chills, neck pain, and neck stiffness. He was found to have a bloodstream infection and meningitis. He is improving with medical treatment. Which of the following is the most likely pathogen?Listeria monocytogenesAn outbreak with a foodborne mode of transmission has which one of the following characteristics?Illness tends to occur in a specific geographic and demographic distributionCalculate the secondary attack rate for this scenario. In a family of 6, the 2 parents are immune and 4 children are susceptible. One child acquires measles and exposes the whole family. In a short time, 2 other children also acquire measles. What is the secondary attack rate?Primary = 1/4 Secondary= 2/3Chain of infection for a virusAgent = virus Reservoir = humans Portal of exit = resp tract trans = person- person Portal of entry = oral Susceptible host = humansMI vaccine exemptionsreligious, medical, and philosophicalA state health dept wants to set up surveillance for Hep A infection. Describe how each type of surveillance can be used.P: practitioners report cases to SHD A: Enhanced testing in at risk groups Syndromic: SHD actively monitors emergency rooms and facilities for reports of symptoms of Hep A Sentinel: SHD identifies select hospitals in specific areas to regularly monitor the occurrence of Hep AHow does the story of Kodo relate to the gov authority and PH? Do you think Kodo should have been tested and why?-State had power to decide in the best interest of the public. Under the const, state has authority and resp to protect PH and power -Studies had not been done on rabies in ferrets, couldn't guarantee vaccine effectiveness -Set precedent3 Questions PH Officials should ask when using law to protect the public's health? How do these apply to school vaccination exclusionary policies.1) Do I have authority/can I: Under the MI PH code and Zucht v king case, states legally are allowed and have the power to exclude students from school who have not received vaccinations unless there are medical exemptions, religious, or philosophical. The state has a duty to protect the general health. 2) Does law leave me no choice/must I: the state has the duty to protect the health of the public. It must consider the effects of exclusionary policies on a larger scale, i.e. protecting the health of general population of students. 3) How should I exercise my discretion/should I: