Differences in Pertussis Incidence by Race and Ethnicity in the United States, 2010-2017.

Background: An increased pertussis burden has been demonstrated among Hispanic or Latino and American Indian or Alaska Native (AI/AN) infants. However, data on potential disparities among other age and racial groups are limited. Methods: We analyzed pertussis cases reported through Enhanced Pertussis Surveillance from 2010 to 2017. Pertussis and severe pertussis incidence were calculated by race (White, Black or African American, AI/AN, and Asian or Pacific Islanders), ethnicity (Hispanic or Latino and non-Hispanic or non-Latino), and age. Results: Compared with White persons, overall incidence was lower among Black or African American (incidence rate ratio [IRR], .57; 95% confidence interval [CI], .53-.61), AI/AN (IRR, 0.65; 95% CI, .58-.72), and Asian or Pacific Islander persons (IRR, 0.39; 95% CI, .35-.43). Overall incidence of pertussis was higher (1.5-fold; 95% CI, 1.37-1.60) among Hispanic or Latino compared with non-Hispanic or non-Latino adults, potentially related to household size or lower pertussis vaccine uptake among adult Hispanic or Latino cases. Severe pertussis incidence was similar among Black or African American and AI/AN persons compared with White persons. Among infants, severe pertussis incidence was 1.4-fold higher (95% CI, 1.03-1.82) among Black or African American infants than among White infants, and 2.1-fold higher (95% CI, 1.67-2.57) among Hispanic or Latino infants than non-Hispanic or non-Latino infants. Conclusions: The contrast between lower reported incidence but similar or higher severe pertussis incidence among Black or African American and AI/AN persons compared with White persons warrants further investigation and may reflect underdiagnosis or underreporting of mild disease.

Pertussis Infections Among Pregnant Women in the United States, 2012-2017.

BACKGROUND: Little is known about pertussis among pregnant women, a population at increased risk for severe morbidity from respiratory infections such as influenza. We used the Centers for Disease Control and Prevention's Enhanced Pertussis Surveillance (EPS) system to describe pertussis epidemiology among pregnant and nonpregnant women of childbearing age. METHODS: Pertussis cases in women aged 18-44 years with cough onset between 1 January 2012 and 31 December 2017 were identified in 7 EPS states. Surveillance data were collected through patient and provider interviews and immunization registries. Bridged-race, intercensal population data and live birth estimates were used as denominators. RESULTS: We identified 1582 pertussis cases among women aged 18-44 years; 5.1% (76/1499) of patients with a known pregnancy status were pregnant at cough onset. Of the pregnant patients with complete information, 81.7% (49/60) reported onset during the second or third trimester. The median ages of pregnant and nonpregnant patients were 29.0 and 33.0 years, respectively. Most pregnant and nonpregnant patients were White (78.3% vs. 86.4%, respectively; P = .09) and non-Hispanic (72.6% vs. 77.3%, respectively; P = .35). The average annual incidence of pertussis was 7.7/100000 among pregnancy women and 7/3/100000 among nonpregnant women. Compared to nonpregnant patients, more pregnant patients reported whoop (41.9% vs. 31.3%, respectively), posttussive vomiting (58.1% vs. 47.9%, respectively), and apnea (37.3% vs. 29.0%, respectively); however, these differences were not statistically significant (P values > .05 for all). A similar proportion of pregnant and nonpregnant patients reported ever having received Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine; 31.6% vs. 32.7%, respectively; P = .84). CONCLUSIONS: Our analysis suggests that incidence of pertussis and clinical characteristics of disease are similar among pregnant and nonpregnant women. Continued monitoring is important to further define pertussis epidemiology in pregnant women.

Severe Pertussis Infections in the United States, 2011-2015.

BACKGROUND: The incidence of pertussis in the United States has increased in recent years. While characteristics of severe pertussis infection have been described in infants, fewer data are available in older children and adults. In this analysis, we characterize pertussis infections in hospitalized patients of all ages. METHODS: Cases of pertussis with cough onset from 1 January 2011 through 31 December 2015 from 7 US Emerging Infections Program Network states were reviewed. Additional information on hospitalized patients was obtained through abstraction of the inpatient medical record. Descriptive and multivariable analyses were conducted to characterize severe pertussis infection and identify potential risk factors. RESULTS: Among 15942 cases of pertussis reported, 515 (3.2%) were hospitalized. Three hospitalized patients died. Infants aged <2 months accounted for 1.6% of all pertussis cases but 29.3% of hospitalizations. Infants aged 2-11 months and adults aged ≥65 years also had high rates of hospitalization. Infants aged <2 months whose mothers received acellular pertussis during the third trimester and children aged 2 months to 11 years who were up to date on pertussis-containing vaccines had a 43%-66% reduced risk of hospitalization. Among adolescents aged 12-20 years, 43.5% had a history of asthma, and among adults aged ≥65 years, 26.8% had a history of chronic obstructive pulmonary disease. CONCLUSIONS: Individuals at the extreme ends of life may be the most vulnerable to severe pertussis infections, though hospitalization was reported across all age groups. Continued monitoring of severe pertussis infections will be important to help guide prevention, control, and treatment options.

Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation.

BACKGROUND: Infants aged <1 year are at highest risk for pertussis-related morbidity and mortality. In 2012, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccine was recommended for women during each pregnancy to protect infants in the first months of life; data on effectiveness of this strategy are currently limited. METHODS: We conducted a case-control evaluation among pertussis cases <2 months old with cough onset between 1 January 2011 and 31 December 2014 from 6 US Emerging Infection Program Network states. Controls were hospital-matched and selected by birth certificate. Mothers were interviewed to collect information on demographics, household characteristics, and healthcare providers. Provider-verified immunization history was obtained on mothers and infants. Mothers were considered vaccinated during pregnancy if Tdap was received ≥14 days before delivery; trimester was calculated using Tdap date, infant's date of birth, and gestational age. Odds ratios were calculated using multivariable conditional logistic regression; vaccine effectiveness (VE) was estimated as (1 - odds ratio) × 100%. RESULTS: A total of 240 cases and 535 controls were included; 17 (7.1%) case mothers and 90 (16.8%) control mothers received Tdap during the third trimester of pregnancy. The multivariable VE estimate for Tdap administered during the third trimester of pregnancy was 77.7% (95% confidence interval [CI], 48.3%-90.4%); VE increased to 90.5% (95% CI, 65.2%-97.4%) against hospitalized cases. CONCLUSIONS: Vaccination during pregnancy is an effective way to protect infants during the early months of life. With a continuing resurgence in pertussis, efforts should focus on maximizing Tdap uptake among pregnant women.

Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination-United States, 2010-2012.

BACKGROUND: In 2012, >48000 pertussis cases were reported in the United States. Many cases occurred in vaccinated persons, showing that pertussis vaccination does not prevent all pertussis cases. However, pertussis vaccination may have an impact on disease severity. METHODS: We analyzed data on probable and confirmed pertussis cases reported through Enhanced Pertussis Surveillance (Emerging Infections Program Network) between 2010 and 2012. Surveillance data were collected through physician and patient interview and vaccine registries. We assessed whether having received an age-appropriate number of pertussis vaccines (AAV) (for persons aged ≥3 months) was associated with reduced odds of posttussive vomiting, a marker of more clinically significant illness, or of severe pertussis (seizure, encephalopathy, pneumonia, and/or hospitalization). Adjusted odds ratios were calculated using multivariable logistic regression. RESULTS: Among 9801 pertussis patients aged ≥3 months, 77.6% were AAV. AAV status was associated with a 60% reduction in odds of severe disease in children aged 7 months-6 years in multivariable logistic regression and a 30% reduction in odds of posttussive vomiting in persons aged 19 months-64 years. CONCLUSIONS: Serious pertussis symptoms and complications are less common among AAV pertussis patients, demonstrating that the positive impact of pertussis vaccination extends beyond decreasing risk of disease.

An Assessment of the Cocooning Strategy for Preventing Infant Pertussis-United States, 2011.

BACKGROUND: Infants are at greatest risk for severe pertussis. In 2006, the Advisory Committee on Immunization Practices recommended that adolescents and adults, especially those with infant contact, receive a single dose of Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine). To assess the effectiveness of cocooning, we conducted a case-control evaluation of infant close contacts. METHODS: Pertussis cases aged <2 months with onset between 1 January 2011 and 31 December 2011 were identified in Emerging Infections Program Network sites. For each case, we recruited 3 controls from birth certificates and interviewed identified adult close contacts (CCs) or parents of CCs aged <18 years. Pertussis vaccination was verified through medical providers and/or immunization registries. RESULTS: Forty-two cases were enrolled, with 154 matched controls. Around enrolled infants, 859 CCs were identified (600 adult and 259 nonadult). An average of 5.4 CCs was identified per case and 4.1 CCs per control. Five hundred fifty-four (64.5%) CCs were enrolled (371 adult and 183 non-adult CCs); 119 (32.1% of enrolled) adult CCs had received Tdap. The proportion of Tdap-vaccinated adult CCs was similar between cases and controls (P = .89). The 600 identified adult CCs comprised 172 potential cocoons; 71 (41.3%) potential cocoons had all identified adult CCs enrolled. Of these, 9 were fully vaccinated and 43.7% contained no Tdap-vaccinated adults. The proportion of fully vaccinated case (4.8%) and control (10.0%) cocoons was similar (P = .43). CONCLUSIONS: Low Tdap coverage among adult CCs reinforces the difficulty of implementing the cocooning strategy and the importance of vaccination during pregnancy to prevent infant pertussis.

Continuing Decline in Varicella Incidence After the 2-Dose Vaccination Recommendation-Connecticut, 2009-2014.

Background. Varicella is a highly contagious vaccine-preventable illness. In 1996, the Advisory Committee for Immunization Practices recommended 1 dose of vaccine for children, and in 2006 it recommended 2 doses; Connecticut required 1 dose for school entry in 2000 and 2 doses for school entry starting in 2011. Connecticut varicella incidence overall and among persons aged 1-14 years declined during 2005-2008. We analyzed varicella surveillance data for 2009-2014 to characterize overall and age group-specific trends in the setting of the 2-dose requirement. Methods. Passive surveillance was used to collect data and identify incidence trends and changes in proportions, and these were assessed by χ(2) tests for trend and proportion, respectively. Results. Varicella incidence decreased from 13.8 cases/100 000 persons during 2009 to 5.1 cases/100 000 persons during 2014 (P < .001); significant declines in incidence occurred among children aged 1-4, 5-9, and 10-14 years (P < .01 for each age group). Cases classified as preventable decreased from 44% during 2009 to 25% during 2014 (P < .01); significant declines in percentages of preventable cases occurred only among those aged 5-9 years (P < .05) and 10-14 (P < .01) years. Conclusions. Varicella incidence continued to decline in Connecticut in the setting of the 2-dose school-entry program. Continued surveillance is needed to assess the full influence of the 2-dose recommendation.

Sources of Infant Pertussis Infection in the United States.

BACKGROUND: Pertussis is poorly controlled, with the highest rates of morbidity and mortality among infants. Although the source of infant pertussis is often unknown, when identified, mothers have historically been the most common reservoir of transmission. Despite high vaccination coverage, disease incidence has been increasing. We examined whether infant source of infection (SOI) has changed in the United States in light of the changing epidemiology. METHODS: Cases <1 year old were identified at Enhanced Pertussis Surveillance sites between January 1, 2006 to December 31, 2013. SOI was collected during patient interview and was defined as a suspected pertussis case in contact with the infant case 7 to 20 days before infant cough onset. RESULTS: A total of 1306 infant cases were identified; 24.2% were <2 months old. An SOI was identified for 569 cases. Infants 0 to 1 months old were more likely to have an SOI identified than 2- to 11-month-olds (54.1% vs 40.2%, respectively; P < .0001). More than 66% of SOIs were immediate family members, most commonly siblings (35.5%), mothers (20.6%), and fathers (10.0%); mothers predominated until the transition to siblings beginning in 2008. Overall, the SOI median age was 14 years (range: 0-74 years); median age for sibling SOIs was 8 years. CONCLUSIONS: In contrast to previous studies, our data suggest that the most common source of transmission to infants is now siblings. While continued monitoring of SOIs will optimize pertussis prevention strategies, recommendations for vaccination during pregnancy should directly increase protection of infants, regardless of SOI.

Trends in hospitalizations with primary varicella and herpes zoster during the prevaricella and initial postvaricella and herpes zoster vaccine eras, connecticut, 1994-2012.

Background. The introductions of the varicella vaccine in 1995 and herpes zoster (HZ) vaccine in 2006 have an ongoing potential to modify the epidemiology of both diseases. Analysis of data on hospitalizations can be conducted to examine trends in the occurrence of severe disease over time and to assess the possible impact of vaccination on the incidence of hospitalization. Methods. Statewide hospital discharge data 1994-2012 in Connecticut were used to identify individuals discharged with a diagnosis of varicella and the initial admissions of persons with a discharge diagnosis of HZ in the first or second diagnostic position. Trends in overall age-standardized and age group-specific hospitalization rates for preselected time intervals before and after the introduction of vaccines were examined using Poisson regression models or Mantel-Haenszel χ(2) tests. Results. Beginning in 2001, 5 years after the introduction of varicella vaccine, HZ hospitalization rates decreased significantly in individuals <15 years at an average rate of 19.4% per year through 2012. Among individuals ≥60 years, HZ hospitalization rates increased by 5.1% per year from 2001 to 2006 but decreased by 4.2% per year from 2007 to 2012. Primary varicella hospitalization rates declined 82.9% from the prevaccine era (1994-1995) to the 1-dose era (2001-2005) (P < .001). Rates further decreased significantly in the 2-dose era (2010-2012) among 5 to 9 year olds (100% decrease). Conclusions. Varicella vaccine seems to have had an impact on both varicella and HZ hospitalizations, and introduction of the HZ vaccine may be having an impact on HZ hospitalizations.

Pertactin-negative Bordetella pertussis strains: evidence for a possible selective advantage.

BACKGROUND: A recent increase in Bordetella pertussis without the pertactin protein, an acellular vaccine immunogen, has been reported in the United States. Determining whether pertactin-deficient (PRN(-)) B. pertussis is evading vaccine-induced immunity or altering the severity of illness is needed. METHODS: We retrospectively assessed for associations between pertactin production and both clinical presentation and vaccine history. Cases with isolates collected between May 2011 and February 2013 from 8 states were included. We calculated unadjusted and adjusted odds ratios (ORs) using multivariable logistic regression analysis. RESULTS: Among 753 isolates, 640 (85%) were PRN(-). The age distribution differed between cases caused by PRN(-) B. pertussis and cases caused by B. pertussis producing pertactin (PRN(+)) (P = .01). The proportion reporting individual pertussis symptoms was similar between the 2 groups, except a higher proportion of PRN(+) case-patients reported apnea (P = .005). Twenty-two case-patients were hospitalized; 6% in the PRN(+) group compared to 3% in the PRN(-) group (P = .11). Case-patients having received at least 1 pertussis vaccine dose had a higher odds of having PRN(-) B. pertussis compared with unvaccinated case-patients (adjusted OR = 2.2; 95% confidence interval [CI], 1.3-4.0). When restricted to case-patients at least 1 year of age and those age-appropriately vaccinated, the adjusted OR increased to 2.7 (95% CI, 1.2-6.1). CONCLUSIONS: The significant association between vaccination and isolate pertactin production suggests that the likelihood of having reported disease caused by PRN(-) compared with PRN(+) strains is greater in vaccinated persons. Additional studies are needed to assess whether vaccine effectiveness is diminished against PRN(-) strains.

Impact of requiring influenza vaccination for children in licensed child care or preschool programs--Connecticut, 2012-13 influenza season.

Preschool-aged children are at increased risk for severe influenza-related illness and complications. Congregate child care settings facilitate influenza transmission among susceptible children. To protect against influenza transmission in these settings, in September 2010, Connecticut became the second U.S. state (after New Jersey) to implement regulations requiring that all children aged 6-59 months receive at least 1 dose of influenza vaccine each year to attend a licensed child care program. To evaluate the impact of this regulation on vaccination levels and influenza-associated hospitalizations during the 2012-13 influenza season, vaccination data from U.S. and Connecticut surveys and the Emerging Infections Program (EIP) were analyzed. After the regulation took effect, vaccination rates among Connecticut children aged 6-59 months increased from 67.8% during the 2009-10 influenza season to 84.1% during the 2012-13 season. During the 2012-13 influenza season, among all 11 EIP surveillance sites, Connecticut had the greatest percentage decrease (12%) in the influenza-associated hospitalization rate from 2007-08 among children aged ≤4 years. Additionally, the ratio of the influenza-associated hospitalization rates among children aged ≤4 years to the overall population rate (0.53) was lower than for any other EIP site. Requiring vaccination for child care admission might have helped to increase vaccination rates in Connecticut and reduced serious morbidity from influenza.

Effect of vaccination coordinators on socioeconomic disparities in immunization among the 2006 Connecticut birth cohort.

OBJECTIVES: We examined socioeconomic status (SES) disparities and the influence of state Immunization Action Plan-funded vaccination coordinators located in low-SES areas of Connecticut on childhood vaccination up-to-date (UTD) status at age 24 months. METHODS: We examined predictors of underimmunization among the 2006 birth cohort (n = 34,568) in the state's Immunization Information System, including individual demographic and SES data, census tract SES data, and residence in an area with a vaccination coordinator. We conducted multilevel logistic regression analyses. RESULTS: Overall, 81% of children were UTD. Differences by race/ethnicity and census tract SES were typically under 5%. Not being UTD at age 7 months was the strongest predictor of underimmunization at age 24 months. Among children who were not UTD at age 7 months, only Medicaid enrollment (adjusted odds ratio [AOR] = 0.6; 95% confidence interval [CI] = 0.5, 0.7) and residence in an area with a vaccination coordinator (AOR = 0.7; 95% CI = 0.6, 0.9) significantly decreased the odds of subsequent underimmunization. CONCLUSIONS: SES disparities associated with underimmunization at age 24 months were limited. Efforts focused on vaccinating infants born in low SES circumstances can minimize disparities.

A 2009 varicella outbreak in a Connecticut residential facility for adults with intellectual disability.

We investigated a varicella outbreak in a residential facility for adults with intellectual disabilities. A case of varicella was defined as a generalized maculopapular rash that developed in a facility resident or employee. Immunoglobulin M testing was conducted on serologic samples, and polymerase chain reaction testing was performed on environmental and skin lesion samples. Eleven cases were identified among 70 residents and 2 among ∼145 staff. An unrecognized case of herpes zoster was the likely source. Case patients first entered any residential facility at a younger age than non-case residents (9.5 vs 15.0 years; P < .01). Varicella zoster virus DNA was detected 2 months after the outbreak in environmental samples obtained from case patients' residences. This outbreak exemplifies the potential for at-risk pockets of varicella-susceptible adults, especially among those who have lived in residential facilities from a young age. Evidence of immunity should be verified for all adults and healthcare staff in similar residential settings.

Lyme disease trends: Delaware, 2000 - 2004.

BACKGROUND: Lyme disease is the most common vector-borne disease in the United States, with 19,804 cases reported in 2004. During 1992-1998, Delaware was among the top 10 states with the highest incidence rates in the United States. We analyzed Delaware Lyme disease surveillance data for the reporting period of 2000-2004 to characterize trends, identify populations at high risk, examine the frequency of the major clinical features of disease, and report antibiotic usage patterns among reporting clinicians. METHODS: A Lyme disease case was defined as a person with physician-diagnosed erythema migrans (EM) or at least one objective late manifestation of the disease (e.g., musculoskeletal, cardiovascular, or neurologic) with laboratory confirmation. We merged the information contained in the Delaware Electronic Reporting Surveillance System (DERSS) with an existing database containing case reports of Lyme disease collected at the Delaware Division of Public Health (DPH) for 2000-2004. The 2000 United States Census Bureau data relevant to Delaware was used to calculate incidence rates. Annual incidence rates by age, sex, county, race, and ZIP Code Tabulation Area (ZCTA) were calculated. Frequency of EM and other late manifestations of Lyme disease as well as antibiotic and median duration of use were calculated. RESULTS: During 2000-2004, a total of 962 confirmed cases of Lyme disease were reported to DPH, for a crude mean incidence rate of 24.6 cases/100,000 persons/year (95% confidence interval [CI], 22.8-26.3). The annual incidence rate remained approximately constant during 2000-2004, with no statistically significant rate difference among the reporting years. Highest incidence rates were observed in Kent County, at 27.8 cases/ 100,000 persons/year (95% CI, 23.0-32.3). Age-related incidence followed a bimodal distribution, with the initial peak among children aged 5-14 years, followed by a second peak among adults aged 60-64 years. Males were disproportionately represented among the age ranges of 5-19 years, 60-69 years, 75-79 years, and >85 years. Lyme disease was most commonly diagnosed during June, July, and August. Fifty-one percent of reported cases had physician-diagnosed EM. CONCLUSIONS: Lyme disease prevention programs should specifically target populations at high risk, as defined in this report. A substantial percentage of reported cases lacked physician-diagnosed EM. Physicians should be aware of the spectrum of Lyme disease clinical manifestations and the local Lyme disease epidemiology to best serve their patient population.