{"id":10209,"date":"2025-03-01T14:03:08","date_gmt":"2025-03-01T19:03:08","guid":{"rendered":"https:\/\/dhss.delaware.gov\/dph\/dhan244\/"},"modified":"2025-03-02T00:49:57","modified_gmt":"2025-03-02T05:49:57","slug":"dhan244","status":"publish","type":"page","link":"https:\/\/dhss.delaware.gov\/dph\/php\/alerts\/dhan244\/","title":{"rendered":"php\/alerts\/dhan244 ~  Division of Public Health &#8212; Health Alert  &#8211; Delaware Health and Social Services &#8211; State of Delaware"},"content":{"rendered":"<div data-swiftype-index=\"true\">\n\n\n\n  <br>\n\n\n\n  <div class=\"container\" id=\"main_header\"> \n\n    <!-- BEGIN readspeaker div -->\n\n    <div class=\"rs_skip rsbtn rs_preserve\" id=\"readspeaker_button1\">\n\n      <a accesskey=\"L\" class=\"rsbtn_play\" href=\"https:\/\/app-na.readspeaker.com\/cgi-bin\/rsent?customerid=7262&#038;lang=en_us&#038;readid=main_content&#038;url=https:\/\/dhss.delaware.gov\/dph\/php\/alerts\/dhan244.html\" title=\"Listen to this page using ReadSpeaker\">\n\n        <span class=\"rsbtn_left rsimg rspart\"><span class=\"rsbtn_text\"><span>Listen<\/span><\/span><\/span>\n\n        <span class=\"rsbtn_right rsimg rsplay rspart\"><\/span>\n\n      <\/a>\n\n    <\/div>\n\n    <!-- END readspeaker div -->\n\n\n\n    \n\n    <header class=\"pull-left\">\n\n      <h1>Delaware Health Alert Network #<!--[type=EDIT name=\"DHAN Number\"]-->244 <!--[END]--> <\/h1>\n\n      <h2> <!--[type=EDIT name=\"DHAN Date\"]-->February 21, 2011 1:55pm <!--[END]--> <\/h2>\n\n    <\/header>\n\n  <\/div><br>\n\n \n\n  <div class=\"container\">\n\n    <div class=\"row\">\n\n      <div class=\"col-md-3\" id=\"leftCol\">\n\n        <div class=\"panel-group\" id=\"accordion\">\n\n          <div class=\"panel sectionmenu_panel\">\n\n            <div class=\"panel-heading\">\n\n              <p class=\"panel-title\"><a class=\"agency_nav\" data-parent=\"#accordion\" data-toggle=\"collapse\" href=\"#collapseOne\"><strong><i class=\"fa fa-align-justify fa-fw\"><\/i> Public Health Menu<\/strong><\/a><\/p>\n\n            <\/div>\n\n\n\n            <div class=\"panel-collapse collapse in\" id=\"collapseOne\">\n\n              <div class=\"panel-body\" id=\"clf_nav\">\n\n                  <ul class=\"nav nav-stacked nav-pills-clf\" id=\"agency_sidebar\">\n    <li><a href=\"\/dph\/\"><h2>Home <i class=\"fa fa-home fa-fw\"><\/i><\/h2><\/a><\/li>\n    <li class=\"toplevel\"><a data-parent=\"#agency_sidebar\" data-toggle=\"collapse\" href=\"#HomeMenu\"><h2>About <i class=\"fa fa-caret-right fa-fw\"><\/i><\/h2><\/a>\n      <ul class=\"panel-collapse collapse\" id=\"HomeMenu\">\n        <li><a href=\"\/dph\/about.html\">About DPH<\/a><\/li>\n        <li><a href=\"\/dph\/sections.html\">Sections &#038; 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You may call the DPH Bureau of Epidemiology at 1-888-295-5156 if you need additional information.\n\n\n<\/p>\n\n\n<p>\n\n\n  <em><strong>Summary:<\/strong>\u00a0\u00a0 With the continuing resurgence of pertussis, health care professionals will likely see more\n\n\n  patients with suspected pertussis. <strong>Proper testing criteria, timing of testing, specimen collection techniques, protocols for\n\n\n  avoiding specimen contamination, and appropriate interpretation of test results are all necessary to ensure that Polymerase Chain\n\n\n  Reaction (PCR) reliably informs patient diagnosis.<\/strong> PCR is an important tool for timely diagnosis of pertussis and is\n\n\n  increasingly available to clinicians. PCR is a molecular technique used to detect DNA sequences of the Bordetella pertussis bacterium and\n\n\n  unlike culture does not require viable (live) bacteria present in the specimen. Despite this advantage, PCR can give results that are\n\n\n  falsely-negative or falsely-positive. The following compilation of best practices is intended to help health care professionals optimize\n\n\n  the use of PCR testing for pertussis by avoiding some of the more common pitfalls leading to inaccurate results.<\/em>\n\n\n<\/p>\n\n\n<h3>\n\n\n  Recommendations for Testing\n\n\n<\/h3><br>\n\n\n<h4>\n\n\n  Whom should you test?\n\n\n<\/h4>\n\n\n<p>\n\n\n  <strong>Only patients with signs and symptoms consistent with pertussis should be tested by PCR to confirm the diagnosis.<\/strong> For\n\n\n  guidance in distinguishing signs and symptoms of pertussis from those of other conditions, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/features.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/features.html<\/a>.\u00a0Testing asymptomatic\n\n\n  persons should be avoided as it increases the likelihood of obtaining falsely-positive results. Asymptomatic close contacts of confirmed\n\n\n  cases should <strong>not<\/strong> be tested and testing of contacts should <strong>not<\/strong> be used for post-exposure prophylaxis\n\n\n  decisions.\n\n\n<\/p>\n\n\n<h4>\n\n\n  When should you test?\n\n\n<\/h4>\n\n\n<p>\n\n\n  <strong>When possible, you should test patients for pertussis during the first 3 weeks of cough<\/strong> when bacterial DNA is still\n\n\n  present in the nasopharynx, because after the fourth week of cough, the amount of bacterial DNA rapidly diminishes, increasing the risk\n\n\n  of obtaining falsely-negative results by PCR. For more information on diagnostic testing, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/diagnosis-confirmation.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/diagnosis-confirmation.html<\/a>.\n\n\n<\/p>\n\n\n<p>\n\n\n  Also, PCR testing after 5 days of antibiotic use is unlikely to be of benefit, because PCR testing following antibiotic therapy also can\n\n\n  result in falsely-negative findings, although the exact duration of positivity following antibiotic use is not well understood.\n\n\n<\/p>\n\n\n<h4>\n\n\n  How should you obtain specimens?\n\n\n<\/h4>\n\n\n<p>\n\n\n  <strong>You should obtain specimens for PCR by aspiration or swabbing the posterior nasopharynx<\/strong>, rather than by throat swabs or\n\n\n  anterior nasal swabs which both have unacceptably low rates of DNA recovery and should therefore <strong>not<\/strong> be used for\n\n\n  pertussis diagnosis. For more information, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/specimen-collection.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/specimen-collection.html<\/a>.\n\n\n<\/p>\n\n\n<h4>\n\n\n  What should you do to avoid contamination of clinical specimens with pertussis DNA?\n\n\n<\/h4>\n\n\n<p>\n\n\n  <strong>Some pertussis vaccines<sup>1<\/sup>have been found to contain PCR-detectable <em>B. pertussis<\/em> DNA. Environmental sampling\n\n\n  has identified <em>B. pertussis<\/em> DNA from these vaccines in clinic environments.<\/strong>\n\n\n<\/p>\n\n\n<p>\n\n\n  <strong>While DNA in the vaccines does not impact the safety or immunogenicity, accidental transfer of the DNA from environmental\n\n\n  surfaces to a clinical specimen can result in specimen contamination and falsely-positive results.<\/strong> If health care professionals\n\n\n  adhere to good practices, there is no need to switch vaccines. Clinicians should adhere to the following vaccine preparation and\n\n\n  administration best practices and basic infection-control measures, to prevent cross-contamination.\n\n\n<\/p>\n\n\n<h4>\n\n\n  Best Practices for Preparing and Administering Vaccines\n\n\n<\/h4>\n\n\n<ul>\n\n\n  <li>Prepare and administer vaccines in areas separate from pertussis specimen collection because doing so may reduce the opportunity for\n\n\n  cross contamination of clinical specimens.\n\n\n  <\/li>\n\n\n  <li>Take care to avoid contamination of surfaces when preparing and administering vaccines.\n\n\n  <\/li>\n\n\n<\/ul>\n\n\n<h4>\n\n\n  Adherence to Basic Infection-control Measures\n\n\n<\/h4>\n\n\n<ul>\n\n\n  <li>Wearing clean gloves immediately before and during specimen collection or vaccine preparation and administration with immediate\n\n\n  disposal of gloves after the procedure, and\n\n\n  <\/li>\n\n\n  <li>Cleaning clinic surfaces using a 10% bleach solution to reduce the amount of nucleic acids in the clinic environment.\n\n\n  <\/li>\n\n\n<\/ul>\n\n\n<p>\n\n\n  The use of liquid transport media likely also contributes to falsely-positive results from contaminant DNA. When using liquid transport\n\n\n  media, DNA that is accidentally transferred from hands to the swab shaft can be washed off into the liquid medium which freely circulates\n\n\n  around the transport tube; this liquid is later extracted to obtain DNA for PCR testing. Use of a semisolid or non-liquid transport media\n\n\n  or transport of a dry swab without media should prevent contaminant DNA on the swab shaft from reaching the part of the specimen that is\n\n\n  later extracted. If using liquid transport medium, the swab stick should be handled with care and only above the red line or indentation\n\n\n  which marks where the shaft is snapped off after insertion into the medium. Performing NP aspiration rather than swabbing the NP may also\n\n\n  prevent contamination from occurring as the aspirate kit (syringe or bulb style) is a closed system at the point of specimen collection.\n\n\n<\/p>\n\n\n<h3>\n\n\n  Recommendations, Understanding and Interpreting PCR Results\n\n\n<\/h3>\n\n\n<p>\n\n\n  PCR assays for pertussis are not standardized across clinical laboratories. Testing methods, DNA targets used, and result interpretation\n\n\n  criteria vary, and laboratories do not use the same cutoffs for determining a positive result. With PCR, high cycle threshold (Ct) values\n\n\n  indicate low levels of amplified DNA; for pertussis, these values may still indicate infection but can also be the result of specimens\n\n\n  contaminated with DNA from the environment at the time of specimen collection. Clinical laboratories might report high Ct values as any\n\n\n  of the following: positive, detected, indeterminate, or equivocal. In addition, most clinical laboratories use a single target PCR for\n\n\n  IS<em>481<\/em>, which is present in multiple copies in <em>B. pertussis<\/em> and in lesser quantities in <em>B. holmesii<\/em> and <em>B.\n\n\n  bronchiseptica<\/em>. Because this DNA sequence is present in multiple copies, IS<em>481<\/em> is especially susceptible to\n\n\n  falsely-positive results. Use of multiple targets may improve specificity of PCR assays for pertussis. <strong>Clinicians are encouraged\n\n\n  to inquire about which PCR target or targets are used by their laboratories. Interpretation of PCR results, especially those with high Ct\n\n\n  values, should be done in conjunction with an evaluation of signs and symptoms and available epidemiological information.<\/strong>\n\n\n<\/p>\n\n\n<h3>\n\n\n  For more information:\n\n\n<\/h3>\n\n\n<ul>\n\n\n  <li>For the entire guidance on PCR best practices in diagnosing pertussis, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/diagnosis-pcr-bestpractices.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/diagnosis-pcr-bestpractices.html<\/a>\n\n\n  <\/li>\n\n\n  <li>For distinguishing clinical features of pertussis, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/features.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/features.html<\/a>\n\n\n  <\/li>\n\n\n  <li>For more information on diagnostic testing, see <a href=\"http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/index.html\">http:\/\/www.cdc.gov\/pertussis\/clinical\/diagnostic-testing\/index.html<\/a>\n\n\n  <\/li>\n\n\n  <li>CDC\u2019s toll-free information line, 800-CDC-INFO (800-232-4636) TTY: (888) 232-6348, is available 24 hours a day, every day.\n\n\n  <\/li>\n\n\n<\/ul>\n\n\n<p>\n\n\n  ________________________________\n\n\n<\/p>\n\n\n<p>\n\n\n  <sup>1<\/sup> Vaccines shown to contain PCR-detectable DNA include Pentacel\u00ae, Daptacel\u00ae, and Adacel\u00ae. Leber A et al. Detection\n\n\n  of <em>Bordetella pertussis<\/em> DNA in Acellular Vaccines and in Environmental Samples from Pediatric Physician Offices, in 2010\n\n\n  Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC): Boston, USA.\n\n\n<\/p>\n\n\n<p>\n\n\n  ************************************\n\n\n<\/p>\n\n\n<p>\n\n\n  You are receiving this email because you are a registered member of the Delaware Health Alert Network. If you are not a member and would\n\n\n  like to subscribe, please register at <a href=\"https:\/\/healthalertde.org\">https:\/\/healthalertde.org<\/a>\n\n\n<\/p><!--[END]-->\n\n  \n\n        <div class=\"panel panel-danger\">\n\n          <div class=\"panel-heading\">    \n\n      <h2>Categories of Health Alert messages:<\/h2>\n\n       <\/div>\n\n       <div class=\"panel-body\">\n\n      <ul>\n\n        <li><strong>Health Alert:<\/strong> Conveys the highest level of importance; warrants immediate action or attention.<\/li>\n\n        <li><strong>Health Advisory:<\/strong> Provides important information for a specific incident or situation; may not require immediate action.<\/li>\n\n        <li><strong>Health Update:<\/strong> Provides updated information regarding an incident or situation; unlikely to require immediate action.<\/li>\n\n            <\/ul>\n\n         <div><strong>NOTE: This page is for informational purposes only and dated material (e.g. temporary websites) may not be available.<\/strong><\/div>\n\n          <\/div> \n\n        <\/div><br>  \n\n\n\n      <\/div>\n\n    <\/div>\n\n  <\/div><!-- \/container -->\n\n  <\/div>","protected":false},"excerpt":{"rendered":"<p>Listen Delaware Health Alert Network #244 February 21, 2011 1:55pm Public Health Menu Home About About DPH Sections &#038; Programs Office Locations Contact Info Calendar Services A-Z Services Air &#038; Water Quality Birth, Death, &#038; Marriage Records Clinics Health Data &#038; Statistics Emergency Preparedness Health &#038; Wellness Healthy Homes Healthy Workplaces Laboratory Restaurant Inspections Screening [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":0,"parent":9294,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"class_list":["post-10209","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/pages\/10209","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/comments?post=10209"}],"version-history":[{"count":1,"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/pages\/10209\/revisions"}],"predecessor-version":[{"id":11385,"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/pages\/10209\/revisions\/11385"}],"up":[{"embeddable":true,"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/pages\/9294"}],"wp:attachment":[{"href":"https:\/\/dhss.delaware.gov\/dph\/wp-json\/wp\/v2\/media?parent=10209"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}