Impact and cost-effectiveness of a second tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine dose to prevent pertussis in the United States.

INTRODUCTION: The United States experienced a substantial increase in reported pertussis cases over the last decade. Since 2005, persons 11 years and older have been routinely recommended to receive a single dose of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine. The objective of this analysis was to evaluate the potential impact and cost-effectiveness of recommending a second dose of Tdap. METHODS: A static cohort model was used to calculate the epidemiologic and economic impact of adding a second dose of Tdap at age 16 or 21 years. Projected costs and outcomes were examined from a societal perspective over a 20-year period. Quality-adjusted Life Years (QALY) saved were calculated. RESULTS: Using baseline pertussis incidence from the National Notifiable Diseases Surveillance System, Tdap revaccination at either age 16 or 21 years would reduce outpatient visits by 433 (5%) and 285 (4%), and hospitalization cases by 7 (7%) and 5 (5%), respectively. The costs per QALY saved with a second dose of Tdap were approximately US $19.7 million (16 years) and $26.2 million (21 years). In sensitivity analyses, incidence most influenced the model; as incidence increased, the costs per QALY decreased. To a lesser degree, initial vaccine effectiveness and waning of effectiveness also affected cost outcomes. Multivariate sensitivity analyses showed that under a set of optimistic assumptions, the cost per QALY saved would be approximately $163,361 (16 years) and $204,556 (21 years). CONCLUSION: A second dose of Tdap resulted in a slight decrease in the number of cases and other outcomes, and that trend is more apparent when revaccinating at age 16 years than at age 21 years. Both revaccination strategies had high dollar per QALY saved even under optimistic assumptions in a multivariate sensitivity analysis.

Serogroup A meningococcal conjugate (PsA-TT) vaccine coverage and measles vaccine coverage in Burkina Faso--implications for introduction of PsA-TT into the Expanded Programme on Immunization.

BACKGROUND: A new serogroup A meningococcal conjugate vaccine (PsA-TT, MenAfriVac™) has been developed to combat devastating serogroup A Neisseria meningitis (MenA) epidemics in Africa. A mass immunization campaign targeting 1-29 year olds was conducted in Burkina Faso in December 2010. Protection of subsequent infant cohorts will be necessary through either introduction of PsA-TT into the routine Expanded Programme on Immunization (EPI) or periodic repeat mass vaccination campaigns. OBJECTIVES: To inform future immunization policy for PsA-TT vaccination of infants through a comparison of PsA-TT campaign vaccination coverage and routine measles-containing vaccine (MCV) coverage in Burkina Faso. METHODS: A national survey was conducted in Burkina Faso during December 17-27, 2011 using stratified cluster sampling to assess PsA-TT vaccine coverage achieved by the 2010 nationwide immunization campaign among 2-30 year olds and routine MCV coverage among 12-23 month olds. Coverage estimates and 95% Confidence Intervals (CI) were calculated, reasons for non-vaccination and methods of campaign communication were described, and a multivariable analysis for factors associated with vaccination was conducted. RESULTS: National overall PsA-TT campaign coverage was 95.9% (95% CI: 95.0-96.7) with coverage greater than 90% all 13 regions of Burkina Faso. National overall routine MCV coverage was 92.5% (95% CI: 90.5-94.1), but ranged from 75.3% to 95.3% by region. The primary predictor for PsA-TT vaccination among all age groups was a head of household informed of the campaign. PsA-TT vaccination was more likely in residents of rural settings, whereas MCV vaccination was more likely in residents of urban settings. CONCLUSION: Overall national vaccination rates in Burkina Faso were similar for PsA-TT and MCV vaccine. The regions with MCV coverage below targets may be at risk for sub-optimal vaccination coverage if PsA-TT is introduced in EPI. These results highlight the need for assessments of routine vaccination coverage to guide PsA-TT immunization policy in meningitis belt countries.

Pregnancy dose Tdap and postpartum cocooning to prevent infant pertussis: a decision analysis.

BACKGROUND: Infants <2 months of age are at highest risk of pertussis morbidity and mortality. Until recently, the US Advisory Committee on Immunization Practices (ACIP) recommended protecting young infants by "cocooning" or vaccination of postpartum mothers and other close contacts with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed (Tdap) booster vaccine. ACIP recommends pregnancy vaccination as a preferred and safe alternative to postpartum vaccination. The ACIP cocooning recommendation has not changed. METHODS: We used a cohort model reflecting US 2009 births and the diphtheria-tetanus-acellular pertussis schedule to simulate a decision and cost-effectiveness analysis of Tdap vaccination during pregnancy compared with postpartum vaccination with or without vaccination of other close contacts (ie, cocooning). We analyzed infant pertussis cases, hospitalizations, and deaths, as well as direct disease, indirect, and public health costs for infants in the first year of life. All costs were updated to 2011 US dollars. RESULTS: Pregnancy vaccination could reduce annual infant pertussis incidence by more than postpartum vaccination, reducing cases by 33% versus 20%, hospitalizations by 38% versus 19%, and deaths by 49% versus 16%. Additional cocooning doses in a father and 1 grandparent could avert an additional 16% of cases but at higher cost. The cost per quality-adjusted life-year saved for pregnancy vaccination was substantially less than postpartum vaccination ($414 523 vs $1 172 825). CONCLUSIONS: Tdap vaccination during pregnancy could avert more infant cases and deaths at lower cost than postpartum vaccination, even when postpartum vaccination is combined with additional cocooning doses. Pregnancy dose vaccination is the preferred alternative to postpartum vaccination for preventing infant pertussis.

Qualitative assessment of pertussis diagnostics in United States laboratories.

BACKGROUND: United States national surveillance data show that the use of culture for pertussis diagnostics has sharply declined, whereas polymerase chain reaction (PCR) is now the most common testing method. PCR testing for pertussis is rapid and sensitive, but the lack of standardization and variable specificity is concerning. METHODS: A web-based survey containing 12 questions was sent to public health, commercial and hospital-based US laboratories performing clinical diagnostics to determine the pertussis diagnostics used. An extensive real-time PCR (RT-PCR) questionnaire accompanied a proficiency panel assessing the types of extraction methods, RT-PCR methods and current quality control in place at the laboratories. The proficiency panel of 12 specimens containing Bordetella pertussis at various concentrations and negative controls was created to detect cross-contamination and assess the lower limit of detection. RESULTS: One hundred twenty-three (35%) of 355 respondents from the web-based survey performed diagnostic tests for the presence of B. pertussis. Eighty-three (71%) labs reported performing culture, whereas 67 (54%) labs used PCR. All 41 laboratories that consented to participate in the proficiency exercise used the IS481 RT-PCR target; however, a variety of extraction and RT-PCR methods were employed. The laboratories correctly identified 92% of the B. pertussis specimens, and 5% of the laboratories (1.8% of the panel specimens) reported at least 1 false-positive. CONCLUSIONS: The small percentage of false-positives suggests that adequate procedures are in place to prevent cross-contamination. Differing extraction and PCR methods as well as variable analytic sensitivity emphasize the necessity for an external well-defined quality control program and interlaboratory pertussis PCR harmonization.

Prevention and control of meningococcal disease: recommendations of the Advisory Committee on Immunization Practices (ACIP).

Meningococcal disease describes the spectrum of infections caused by Neisseria meningiditis, including meningitdis, bacteremia, and bacteremic pneumonia. Two quadrivalent meningococcal polysaccharide-protein conjugate vaccines that provide protection against meningococcal serogroups A, C, W, and Y (MenACWY-D [Menactra, manufactured by Sanofi Pasteur, Inc., Swiftwater, Pennsylvania] and MenACWY-CRM [Menveo, manufactured by Novartis Vaccines, Cambridge, Massachusetts]) are licensed in the United States for use among persons aged 2 through 55 years. MenACWY-D also is licensed for use among infants and toddlers aged 9 through 23 months. Quadrivalent meningococcal polysaccharide vaccine (MPSV4 [Menommune, manufactured by sanofi pasteur, Inc., Swiftwater, Pennsylvania]) is the only vaccine licensed for use among persons aged ≥56 years. A bivalent meningococcal polysaccharide protein conjugate vaccine that provides protection against meningococcal serogroups C and Y along with Haemophilus influenzae type b (Hib) (Hib-MenCY-TT [MenHibrix, manufactured by GlaxoSmithKline Biologicals, Rixensart, Belgium]) is licensed for use in children aged 6 weeks through 18 months. This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) regarding prevention and control of meningococcal disease in the United States, specifically the changes in the recommendations published since 2005 (CDC. Prevention and control of meningococcal disease: recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2005;54 [No. RR-7]). As a comprehensive summary of previously published recommendations, this report does not contain any new recommendations; it is intended for use by clinicians as a resource. ACIP recommends routine vaccination with a quadrivalent meningococcal conjugate vaccine (MenACWY) for adolescents aged 11 or 12 years, with a booster dose at age 16 years. ACIP also recommends routine vaccination for persons at increased risk for meningococcal disease (i.e., persons who have persistent complement component deficiencies, persons who have anatomic or functional asplenia, microbiologists who routinely are exposed to isolates of N. meningitidis, military recruits, and persons who travel to or reside in areas in which meningococcal disease is hyperendemic or epidemic). Guidelines for antimicrobial chemoprophylaxis and for evaluation and management of suspected outbreaks of meningococcal disease also are provided.

Leptospirosis outbreak following severe flooding: a rapid assessment and mass prophylaxis campaign; Guyana, January-February 2005.

BACKGROUND: Leptospirosis is a zoonosis usually transmitted through contact with water or soil contaminated with urine from infected animals. Severe flooding can put individuals at greater risk for contracting leptospirosis in endemic areas. Rapid testing for the disease and large-scale interventions are necessary to identify and control infection. We describe a leptospirosis outbreak following severe flooding and a mass chemoprophylaxis campaign in Guyana. METHODOLOGY/PRINCIPAL FINDINGS: From January-March 2005, we collected data on suspected leptospirosis hospitalizations and deaths. Laboratory testing included anti-leptospiral dot enzyme immunoassay (DST), immunohistochemistry (IHC) staining, and microscopic agglutination testing (MAT). DST testing was conducted for 105 (44%) of 236 patients; 52 (50%) tested positive. Four (57%) paired serum samples tested by MAT were confirmed leptospirosis. Of 34 total deaths attributed to leptospirosis, postmortem samples from 10 (83%) of 12 patients were positive by IHC. Of 201 patients interviewed, 89% reported direct contact with flood waters. A 3-week doxycycline chemoprophylaxis campaign reached over 280,000 people. CONCLUSIONS: A confirmed leptospirosis outbreak in Guyana occurred after severe flooding, resulting in a massive chemoprophylaxis campaign to try to limit morbidity and mortality.

Safety assessment of recalled Haemophilus influenzae type b (Hib) conjugate vaccines--United States, 2007-2008.

PURPOSE: On 13 December 2007, Merck & Co., Inc. voluntarily recalled 1.2 million doses of Haemophilus influenzae type b (Hib) vaccines that had been distributed since April 2007 for concerns regarding potential Bacillus cereus contamination. Enhanced postrecall surveillance was conducted to detect vaccine-associated B. cereus infections. METHODS: We reviewed reports involving recalled Hib vaccines received by the Vaccine Adverse Event Reporting System (VAERS) during 1 April 2007-29 February 2008. For each reported death, autopsy review sought evidence of B. cereus infections. For each specified outcome, the proportional reporting ratios (PRRs) were calculated to compare the recalled Hib vaccines with the manufacturer's nonrecalled Hib vaccines in the VAERS databases. On 20 December 2007, we used the Epidemic Information Exchange (Epi-X) to solicit nongastrointestinal vaccine-associated B. cereus infections, and requested B. cereus isolates for genotyping to compare with the manufacturing facility isolate. RESULTS: VAERS received 75 reports involving recalled Hib vaccines; none described a confirmed B. cereus infection. Comparative analyses did not reveal disproportionate reporting of specified outcomes for recalled Hib vaccines. The Epi-X posting triggered one report of vaccine-associated B. cereus bacteremia from a child who received a nonrecalled Hib vaccine manufactured by Merck; the genotypes of isolates from the patient and the manufacturing facility differed. CONCLUSIONS: No evidence of vaccine-associated B. cereus infection had been found in recipients of recalled Hib vaccines. Conducting laboratory surveillance through Epi-X was feasible and may enhance public health response capacities for future vaccine safety emergencies.

MCV vaccination in the presence of vaccine-associated Guillain-Barré Syndrome risk: a decision analysis approach.

The study evaluates the benefits of meningococcal conjugate vaccine (MCV4) vaccination against the burden of vaccine-associated Guillain-Barré Syndrome (GBS) using simulation. An 11-year-old cohort was followed over an 8-year period in a simulation model Table 3 Figs. 1 and 2 to estimate health outcomes to assist decision makers in setting policy. Applying a 3% discount rate, MCV4 vaccination would save 2397 quality-adjusted life years (QALYs) while vaccine-attributable GBS could result in 5 QALYs lost. Based on the result, MCV4 vaccination is strongly favored despite possible vaccine-associated GBS risk.