Mass chemoprophylaxis for control of outbreaks of meningococcal disease.

Although vaccination is the main strategy used to control meningococcal disease outbreaks, mass chemoprophylaxis has also been used as an immediate response to outbreaks, either to supplement vaccination or when vaccination is not possible. However, public health guidelines regarding the use of mass chemoprophylaxis for outbreak control vary by country, partly because the impact of mass chemoprophylaxis on the course of an individual outbreak is difficult to assess. We have reviewed data for the use of mass chemoprophylaxis during 33 outbreaks that occurred both in military populations and in communities and non-military organisations. In most outbreaks, no additional cases of meningococcal disease occurred after mass chemoprophylaxis, or cases occurred only in individuals who had not received prophylaxis. A delay of several weeks was common before cases occurred among prophylaxis recipients. Overall, the outbreak reports that we reviewed suggest that mass chemoprophylaxis might provide temporary protection to chemoprophylaxis recipients during outbreaks.

Effectiveness and Duration of Protection of One Dose of a Meningococcal Conjugate Vaccine.

BACKGROUND: Meningococcal conjugate vaccines were licensed beginning in 2005 on the basis of serologic end points and recommended for use in adolescents. A single dose at age 11 to 12 years was expected to provide protection through late adolescence. We conducted a case-control evaluation of vaccine effectiveness (VE) and duration of protection of a meningococcal (groups A, C, W, and Y) polysaccharide diphtheria toxoid conjugate vaccine (MenACWY-D). METHODS: Cases of culture- or polymerase chain reaction-confirmed serogroup A, C, W, and Y meningococcal disease among adolescents were identified through meningococcal disease surveillance sites in the United States from January 1, 2006, through August 31, 2013. Attempts were made to enroll 4 friend and school controls per case. VE was calculated using the generalized estimating equation, controlling for underlying medical conditions and smoking. RESULTS: Serogroup C accounted for 88 (49%), serogroup Y 80 (44%), and serogroup W 13 (7%) of enrolled cases. Thirty-six (20%) cases and 87 (44%) controls received MenACWY-D. The overall VE estimate 0 to 8 years postvaccination was 69% (51% to 80%); VE was 79% (49% to 91%) at <1 year, 69% (44% to 83%) at 1 to <3 years, and 61% (25% to 79%) at 3 to <8 years. VE was 77% (57% to 88%) against serogroup C and 51% (1% to 76%) against serogroup Y. CONCLUSIONS: MenACWY-D was effective in the first year after vaccination but effectiveness waned 3 to <8 years postvaccination. The estimates of VE from this evaluation informed the Advisory Committee on Immunization Practices in its decision to add a booster dose of MenACWY.

Update: Interim Guidance for Health Care Providers Caring for Women of Reproductive Age with Possible Zika Virus Exposure--United States, 2016.

CDC has updated its interim guidance for U.S. health care providers caring for women of reproductive age with possible Zika virus exposure to include recommendations on counseling women and men with possible Zika virus exposure who are interested in conceiving. This guidance is based on limited available data on persistence of Zika virus RNA in blood and semen. Women who have Zika virus disease should wait at least 8 weeks after symptom onset to attempt conception, and men with Zika virus disease should wait at least 6 months after symptom onset to attempt conception. Women and men with possible exposure to Zika virus but without clinical illness consistent with Zika virus disease should wait at least 8 weeks after exposure to attempt conception. Possible exposure to Zika virus is defined as travel to or residence in an area of active Zika virus transmission ( http://www.cdc.gov/zika/geo/active-countries.html), or sex (vaginal intercourse, anal intercourse, or fellatio) without a condom with a man who traveled to or resided in an area of active transmission. Women and men who reside in areas of active Zika virus transmission should talk with their health care provider about attempting conception. This guidance also provides updated recommendations on testing of pregnant women with possible Zika virus exposure. These recommendations will be updated when additional data become available.

Update: Interim Guidance for Prevention of Sexual Transmission of Zika Virus--United States, 2016.

CDC issued interim guidance for the prevention of sexual transmission of Zika virus on February 5, 2016. The following recommendations apply to men who have traveled to or reside in areas with active Zika virus transmission and their female or male sex partners. These recommendations replace the previously issued recommendations and are updated to include time intervals after travel to areas with active Zika virus transmission or after Zika virus infection for taking precautions to reduce the risk for sexual transmission. This guidance defines potential sexual exposure to Zika virus as any person who has had sex (i.e., vaginal intercourse, anal intercourse, or fellatio) without a condom with a man who has traveled to or resides in an area with active Zika virus transmission. This guidance will be updated as more information becomes available.

Patterns in Zika Virus Testing and Infection, by Report of Symptoms and Pregnancy Status - United States, January 3-March 5, 2016.

CDC recommends Zika virus testing for potentially exposed persons with signs or symptoms consistent with Zika virus disease, and recommends that health care providers offer testing to asymptomatic pregnant women within 12 weeks of exposure. During January 3-March 5, 2016, Zika virus testing was performed for 4,534 persons who traveled to or moved from areas with active Zika virus transmission; 3,335 (73.6%) were pregnant women. Among persons who received testing, 1,541 (34.0%) reported at least one Zika virus-associated sign or symptom (e.g., fever, rash, arthralgia, or conjunctivitis), 436 (9.6%) reported at least one other clinical sign or symptom only, and 2,557 (56.4%) reported no signs or symptoms. Among 1,541 persons with one or more Zika virus-associated symptoms who received testing, 182 (11.8%) had confirmed Zika virus infection. Among the 2,557 asymptomatic persons who received testing, 2,425 (94.8%) were pregnant women, seven (0.3%) of whom had confirmed Zika virus infection. Although risk for Zika virus infection might vary based on exposure-related factors (e.g., location and duration of travel), in the current setting in U.S. states, where there is no local transmission, most asymptomatic pregnant women who receive testing do not have Zika virus infection.

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.

Prevention and control of haemophilus influenzae type b disease: recommendations of the advisory committee on immunization practices (ACIP).

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) regarding prevention and control of Haemophilus influenzae type b (Hib) disease in the United States. As a comprehensive summary of previously published recommendations, this report does not contain any new recommendations; it is intended for use by clinicians, public health officials, vaccination providers, and immunization program personnel as a resource. ACIP recommends routine vaccination with a licensed conjugate Hib vaccine for infants aged 2 through 6 months (2 or 3 doses, depending on vaccine product) with a booster dose at age 12 through 15 months. ACIP also recommends vaccination for certain persons at increased risk for Hib disease (i.e., persons who have early component complement deficiencies, immunoglobulin deficiency, anatomic or functional asplenia, or HIV infection; recipients of hematopoietic stem cell transplant; and recipients of chemotherapy or radiation therapy for malignant neoplasms). This report summarizes current information on Hib epidemiology in the United States and describes Hib vaccines licensed for use in the United States. Guidelines for antimicrobial chemoprophylaxis of contacts of persons with Hib disease also are provided.

Neisseria meningitidis serogroup W, Burkina Faso, 2012.

In 2010, Burkina Faso became the first country to introduce meningococcal serogroup A conjugate vaccine (PsA-TT). During 2012, Burkina Faso reported increases in Neisseria meningitidis serogroup W, raising questions about whether these cases were a natural increase in disease or resulted from serogroup replacement after PsA-TT introduction. We analyzed national surveillance data to describe the epidemiology of serogroup W and genotyped 61 serogroup W isolates. In 2012, a total of 5,807 meningitis cases were reported through enhanced surveillance, of which 2,353 (41%) were laboratory confirmed. The predominant organism identified was N. meningitidis serogroup W (62%), and all serogroup W isolates characterized belonged to clonal complex 11. Although additional years of data are needed before we can understand the epidemiology of serogroup W after PsA-TT introduction, these data suggest that serogroup W will remain a major cause of sporadic disease and has epidemic potential, underscoring the need to maintain high-quality case-based meningitis surveillance after PsA-TT introduction.

Invasive Haemophilus influenzae in the United States, 1999-2008: epidemiology and outcomes.

OBJECTIVES: Introduction of the Haemophilus influenzae type b (Hib) conjugate vaccine has resulted in a dramatic reduction of Hib disease in the U.S. and an increase in the relative importance of infections caused by nontypeable strains. The current project describes the characteristics and clinical outcomes of pediatric and adult patients with invasive H. influenzae (HI) and, through multivariable analysis, identifies risk factors for in-hospital mortality. METHODS: HI cases were identified during 1999-2008 through active surveillance as part of active bacterial core surveillance (ABCs). Multivariable analysis was performed with logistic regression to identify factors predictive of in-hospital death. RESULTS: 4839 cases of HI were identified from 1999-2008. Children accounted for 17.1% of cases and adults 82.9%. Underlying conditions were present in 20.7% of children and 74.8% of adults. In-hospital mortality was highest in cases ≥65 years (21.9%) and <3 months (16.2%). The risk of in-hospital death in children <1 year was higher among those who were prematurely-born (<28 weeks, OR 7.1, 95% CI 3.2-15.6; 28-36 weeks OR 2.1, 95% CI 0.9-4.8) and, among children aged 1-17 years, higher in those with healthcare-associated onset and dialysis (OR 5.66, 95% CI 1.84-17.39; OR 18.11, 95% CI 2.77-118.65). In adults, age ≥40 was associated with death in nontypeable, but not encapsulated, infections. Infections with nontypeable strains increased the risk of death in cases ≥65 years (OR 1.81, 95% CI 1.31-2.52). Healthcare-associated HI, bacteremia without identifiable focus, bacteremic pneumonia, associated cirrhosis, cerebrovascular accident, dialysis, heart failure, and non-hematologic malignancy also increased the risk of death in adults. CONCLUSION: Prematurity in infants, advanced age and certain chronic diseases in adults were associated with an increased risk of in-hospital death. Nontypeable HI was associated with higher mortality in the elderly.

Adolescent vaccination-coverage levels in the United States: 2006-2009.

BACKGROUND: From 2005 through 2007, 3 vaccines were added to the adolescent vaccination schedule: tetanus-diphtheria-acellular pertussis (TdaP); meningococcal conjugate (MenACWY); and human papillomavirus (HPV) for girls. OBJECTIVE: To assess implementation of new adolescent vaccination recommendations. METHODS: Data from the 2006-2009 National Immunization Survey-Teen, an annual provider-verified random-digit-dial survey of vaccination coverage in US adolescents aged 13 to 17 years, were analyzed. Main outcome measures included percentage of adolescents who received each vaccine according to survey year; potential coverage if all vaccines were administered during the same vaccination visit; and, among unvaccinated adolescents, the reasons for not receiving vaccine. RESULTS: Between 2006 and 2009, ≥1 TdaP and ≥1 MenACWY coverage increased from 11% to 56% and 12% to 54%, respectively. Between 2007 and 2009, ≥1 HPV coverage among girls increased from 25% to 44%; between 2008 and 2009, ≥3 HPV coverage increased from 18% to 27%. In 2009, vaccination coverage could have been >80% for Td/TdaP and MenACWY and as high as 74% for the first HPV dose if providers had administered all recommended vaccines during the same vaccination visit. For all years, the top reported reasons for not vaccinating were no knowledge about the vaccine, provider did not recommend, and vaccine is not needed/necessary (for TdaP and MenACWY) and adolescent is not sexually active, no knowledge about the vaccine, and vaccine is not needed/necessary (for HPV). CONCLUSIONS: Adolescent vaccination coverage is increasing but could be improved. Strategies are needed to increase parental knowledge about adolescent vaccines and improve provider recommendation and administration of all vaccines during the same visit.

Compliance with recommendations and opportunities for vaccination at ages 11 to 12 years: evaluation of the 2009 national immunization survey-teen.

OBJECTIVES: To determine vaccination coverage at selected ages and by birth cohort and to assess whether all indicated vaccines were administered during vaccination visits. DESIGN: Population-based cross-sectional study. SETTING: National Immunization Survey-Teen 2009 telephone interview. PARTICIPANTS: United States adolescents aged 13 to 17 years with provider-reported vaccination histories (N = 20 066). MAIN OUTCOME MEASURES: Among all adolescents and by birth cohort: coverage estimates for 3 childhood vaccines (measles-containing, hepatitis B, and varicella) and 3 adolescent vaccines (tetanus-diphtheria and/or tetanus-diphtheria-acellular pertussis, meningococcal-containing, and human papillomavirus for girls) at selected ages. RESULTS: By age 11 years, most adolescents had obtained the childhood vaccines. Receipt of a tetanus-diphtheria and/or tetanus-diphtheria-acellular pertussis vaccine at ages 11 to 12 years increased significantly from the 1991 to 1996 birth cohort (33.8% vs 68.2%, P < .001); receipt of meningococcal-containing vaccine at ages 11 to 12 years increased significantly from the 1993 to 1996 birth cohort (8.4% vs 50.0%, P < .001). Among girls, receipt of human papillomavirus vaccine at ages 11 to 12 years increased significantly from the 1994 to 1996 birth cohort (11.1% vs 30.5%, P < .001). Overall, 54.9% of adolescents received at least 1 vaccination visit at ages 11 to 12 years. Among adolescents who made a vaccination visit at ages 11 to 12 years and were eligible for vaccination, 19.5% did not receive tetanus-diphtheria and/or tetanus-diphtheria-acellular pertussis, 60.9% did not receive meningococcal-containing, and 62.4% did not receive human papillomavirus vaccines. CONCLUSIONS: Receipt of vaccines at the recommended ages of 11 to 12 years appears to be increasing; however, providers often do not administer all indicated vaccines during a vaccination visit.