Risk Of Pertussis Research Articles

A behavioral economics intervention to increase pertussis vaccination among infant caregivers: A randomized feasibility trial

ObjectivesThe incidence of pertussis has tripled in the past five years. Infants can be protected by “cocooning,” or vaccinating household contacts with the Tdap vaccine. However, Tdap coverage for adult caregivers of infants is low. This study evaluated the feasibility and impact of interventions informed by behavioral economics (retail pharmacy vouchers for Tdap vaccines and a celebrity public service announcement) to increase Tdap vaccination among caregivers of young infants. MethodsWe conducted a randomized controlled feasibility trial among adults attending newborn well-child visits at an urban Philadelphia pediatric primary care clinic who were not previously vaccinated with Tdap. Participants were randomized to one of four conditions: ($5-off Tdap voucher vs. free voucher)×(watching a 1min video public service announcement (PSA) about Tdap vaccination vs. no PSA). Tdap vaccination was assessed by tracking voucher redemption and following up with participants by phone. ResultsNinety-five adult caregivers of 74 infants were enrolled in the study (mean age 29.3 years; 61% male; relationship to newborn: 54% father, 33% mother, 13% grandparent or other; caregiver insurance status: 35% Medicaid, 34% private insurance, 32% uninsured). Only 1 subject redeemed the retail pharmacy Tdap voucher. Follow-up interviews suggest that, even with the voucher, significant barriers to vaccination remained including: delaying planned vaccination, perceived inconvenient pharmacy locations, and beliefs about pertussis risk and severity. ConclusionsDespite leveraging existing infrastructure for adult vaccination, results suggest that retail pharmacy vouchers delivered during a newborn visit are not an effective strategy for promoting Tdap. Alternate approaches are needed that prioritize convenience and provide an immediate opportunity to vaccinate when motivation is high.

Reduced risk of pertussis in whole-cell compared to acellular vaccine recipients is not confounded by age or receipt of booster-doses

Several observational studies provide evidence that acellular pertussis vaccines (aP) are less protective against pertussis disease than highly effective whole-cell pertussis vaccines (wP), however, concerns have been raised that some of these findings may be confounded by age. By undertaking age-stratified and restricted analyses on a cohort of Australian children primed with either aP-only, wP-only or mixed pertussis vaccine schedules, we demonstrate that compared to aP the association of wP with increased protection from pertussis is not confounded by age, nor by aP booster-dose receipt.

Choice of measures of vaccination and estimates of risk of pediatric pertussis

BackgroundVaccination uptake at the individual level can be assessed in a variety of ways, including traditional measures of being up-to-date (UTD), measures of UTD that consider dose timing, like age-appropriate vaccination, and risk reduction from individual doses. This analysis compared methods of operationalizing vaccination uptake and corresponding risk of pertussis infection. MethodsCity-wide case-control study of children in Philadelphia aged 3 months through 6 years, between 2001 and 2013. Multiple logistic regression was used to isolate the independent effects of each measure of vaccination uptake and the corresponding relative odds of pertussis. ResultsBeing UTD on vaccinations was associated with a 52% reduction in risk of pertussis (OR 0.48, 95% CI: 0.34, 0.69). Evaluation of delayed receipt of vaccine versus on-time UTD yielded similar results. There was a decrease in risk of pertussis for each additional dose received with the greatest reduction in pertussis infection observed from the first (OR 0.48, 95% CI: 0.28, 0.83) and second dose (OR 0.17, 95% CI: 0.08, 0.34). Additional doses conferred minimal additional protection in this age group. ConclusionExamining vaccination status by individual doses may offer improved predictive capacity for identifying children at risk for pertussis infection compared to the traditional UTD measure.

Risk Factors Associated With Infant Deaths From Pertussis: A Case-Control Study.

In the current era, most pertussis deaths occur in infants <3 months of age. Leukocytosis with lymphocytosis and pneumonia are commonly observed among cases of severe pertussis. Risk factors associated with fatal pertussis were identified by comparing fatal pertussis cases among patients <120 days of age occurring from 1 January 1998 through 26 December 2014, matched by age (<120 days), county of residence, and closest symptom onset date with 1-4 nonfatal hospitalized cases. California Department of Public Health surveillance data were reviewed to identify cases; demographics, clinical presentation, and course were abstracted from corresponding birth and medical records. Logistic regression and classification tree analyses were used to examine the risk of fatal pertussis with respect to identified factors. Fifty-three fatal infant pertussis cases were identified and compared with 183 nonfatal hospitalized pertussis cases. Fatal cases had significantly lower birth weight, younger gestational age, younger age at time of cough onset, and higher peak white blood cell (WBC) and lymphocyte counts. Fatal cases were less likely to have received macrolide antibiotics and more likely to have received steroids or nitric oxide and to develop pulmonary hypertension, seizures, encephalitis, and pneumonia. Additionally, exchange transfusion, extracorporeal membrane oxygenation, and intubation occurred significantly more frequently among fatal cases. In multivariate analyses, peak WBC count, birth weight, intubation, and receipt of nitric oxide were predictors of death. Early recognition of pertussis in young infants and treatment with appropriate antibiotic therapy are important in preventing death. Several risk factors are strongly associated with fatal pertussis in infants.

First pertussis vaccine dose and prevention of infant mortality.

American infants are at highest risk of severe pertussis and death. We investigated the role of ≥1 pertussis vaccinations in preventing pertussis-related deaths and risk markers for death among infants aged <42 days. We analyzed characteristics of fatal and nonfatal infant pertussis cases reported nationally during 1991-2008. Infants were categorized into 2 age groups on the basis of eligibility to receive a first pertussis vaccine dose at age 6 weeks; dose 1 was considered valid if given ≥14 days before illness onset. Multivariable logistic regression was used to estimate the effect of ≥1 pertussis vaccine doses on outcome and risk markers. Pertussis-related deaths occurred among 258 of 45 404 cases. Fatal and nonfatal cases were confirmed by culture (54% vs 49%) and polymerase chain reaction (31% vs 27%). All deaths occurred before age 34 weeks at illness onset; 64% occurred before age 6 weeks. Among infants aged ≥42 days, receiving ≥1 doses of vaccine protected against death (adjusted odds ratio [aOR]: 0.28; 95% confidence interval [CI]: 0.11-0.74), hospitalization (aOR: 0.69; 95% CI: 0.63-0.77), and pneumonia (aOR: 0.80; 95% CI: 0.68-0.95). Risk was elevated for Hispanic ethnicity (aOR: 2.28; 95% CI: 1.36-3.83) and American Indian/Alaska Native race (aOR: 5.15; 95% CI: 2.37-11.2) and lower for recommended antibiotic treatment (aOR: 0.28; 95% CI: 0.16-0.47). Among infants aged <42 days, risk was elevated for Hispanic ethnicity and lower with recommended antibiotic use. The first pertussis vaccine dose and antibiotic treatment protect against death, hospitalization, and pneumonia.

Does working in hospital increases seroprevalence and carrier state against Bordetella pertussis?

Background:Health care environments have been the setting for a number of pertussis outbreaks. Immunity after vaccination wanes overtime leading to a growing population of susceptible adolescents and adults. A number of pertussis outbreaks have occurred in hospitals resulting in transmission to health care workers (HCWs), and other patients. The aim of this study was to assess immunity status of a group of basic medical students and interns who worked in hospitals for about 4 years.Materials and Methods:In a cross-sectional study, we measured the serum antibody titer of cases by enzyme-linked immunosorbent assay test. All 70 subjects have received pertussis vaccine in the routine childhood vaccination schedule. All cases were healthy and had no symptoms of any respiratory diseases. We also obtained a pharyngeal culture on Bordet-Gengou Agar for isolating Bordetella pertussis.Results:The results of B. pertussis pharyngeal culture was positive for 5 (7.1%) cases and negative for 65 (92.9%). The IgM, IgA, and IgG serum antibody was positive in 1.4%, 7.1%, and 11.4% of cases, respectively. The mean age of cases had no significant effect on serum antibody titers (P = 0.23).Conclusions:This study showed that majority of cases do not have protective serum antibody against B. pertussis. Working in hospitals does not affect seroprevalence and carrier state of B. pertussis. Immunization schedules that include no booster doses are at increased risk of pertussis. Due to the importance of the transmission in health care settings, vaccination of HCWs is a priority.

Parental Tdap boosters and infant pertussis: a case-control study.

Although recommended for almost a decade, evidence for field effectiveness of vaccinating close adult contacts of newborn infants against pertussis ("cocooning") is lacking. We evaluated the impact of a government-funded cocoon program during a pertussis epidemic in New South Wales, Australia. We matched all New South Wales laboratory-confirmed pertussis cases aged <4 months with onset between April 1, 2009, to March 30, 2011 to controls from the state birth register by date of birth and area of residence. Parental vaccine receipt was by self-report, with a subset verified. Parents were considered "immunized" if vaccinated ≥4 weeks before case symptom onset. The effectiveness of parental immunization (versus neither vaccinated) was quantified as (1 - odds ratio) × 100%. Case households had fewer immunized mothers (22% vs 32%) or fathers (20% vs 31%) but were more likely to include additional and older children. After adjustment, when both parents met our definition of immunized, risk of pertussis at<4 months of age was reduced by 51% (95% confidence interval 10% to 73%). Maternal vaccination prepregnancy and an immunized father reduced the risk by 51% (95% confidence interval 0% to 76%). Timely parental pertussis boosters provided significant protection. Evidence of protection from maternal vaccination prepregnancy is biologically plausible, and more precise data on the magnitude and duration of this is important for future policy recommendations.

Low pertussis toxin antibody levels in two regional cohorts of Canadian pregnant women

Infants under 6 months of age are at greatest risk of mortality and severe morbidity from pertussis disease. Interventions that increase pertussis protection in newborns are therefore a clear public health imperative. The objective of this study was to assess maternal pertussis toxin antibody (anti-PT) level as a potential source of mother-to-child transfer of pertussis-associated antibodies that may reduce neonatal risk of pertussis disease.Anti-PT level was assessed in a 2013 cohort of pregnant women from two regions in two Canadian provinces, British Columbia and Nova Scotia. Basic demographics, health, and pertussis immunization history were collected, along with blood specimens. Anti-PT levels were compared for self-reported vaccination status and prior pertussis disease. To assess secular trend, a parallel analysis was also undertaken, using anonymized residual sera from a 1996–1997 cohort of pregnant women in British Columbia.A total of 169 pregnant women participated in the study – 50 from Nova Scotia and 119 from British Columbia. The mean and median age of participants from both sites was 31 years of age (range 16–42 years). The lower limit of quantification of the anti-PT assay was 10 ELISA units per milliliter (EU/ml). Overall, 59% of women had anti-PT levels less than 10EU/ml and anti-PT level did not differ with time since last self-reported pertussis vaccination (χ2(2)=3.166, p=0.205). Among a 1996–1997 cohort of pregnant women in British Columbia, 101 of 200 (51%) had anti-PT levels less than 10EU/ml.Our study found that most pregnant women in two geographically disparate health regions in Canada have low residual anti-PT levels, may be vulnerable to pertussis infection themselves, and would unlikely be a source of passive ante- or postnatal transfer of anti-PT to their newborn.

Tdap: the need to educate and immunize.

The resurgence of pertussis is puzzling, especially given the requirement that children complete recommended immunizations prior to school entry. Are adult carriers unknowingly infecting children? What do adult caregivers know about pertussis and the tetanus, diphtheria, and acellular pertussis (Tdap) booster vaccine? How can the incidence of pertussis in children younger than 2 years, a group most at risk for complications of the disease, be reduced? This article examines the incidence of pertussis and strategies to reduce pertussis incidence in the United States. If the need for Tdap vaccine is identified and favorably received by adults, immunization programs can be arranged at worksites to better protect infants who are most at risk for pertussis.

Whooping cough in school age children presenting with persistent cough in UK primary care after introduction of the preschool pertussis booster vaccination: prospective cohort study

Objective To estimate the prevalence and clinical severity of whooping cough (pertussis) in school age children presenting with persistent cough in primary care since the introduction and implementation of the...

Estimating the effectiveness of tetanus-diphtheria-acellular pertussis vaccine (Tdap) for preventing pertussis: evidence of rapidly waning immunity and difference in effectiveness by Tdap brand.

We estimated the vaccine effectiveness (VE) of tetanus-diphtheria-acellular pertussis vaccine (Tdap) for preventing pertussis among adolescents during a statewide outbreak of pertussis in Wisconsin during 2012. We used the population-based Wisconsin Immunization Registry (WIR) to construct a cohort of Wisconsin residents born during 1998-2000 and collect Tdap vaccination histories. Reports of laboratory-confirmed pertussis with onset during 2012 were matched to WIR clients. Incidence rate ratios (IRRs) of pertussis and Tdap VE estimates [(1 - IRR)*100%], by year of Tdap vaccine receipt and brand (Boostrix/Adacel), were estimated using Poisson regression. Tdap VE decreased with increasing time since receipt, with VEs of 75.3% (95% confidence interval [CI], 55.2%-86.5%) for receipt during 2012, 68.2% (95% CI, 60.9%-74.1%) for receipt during 2011, 34.5% (95% CI, 19.9%-46.4%) for receipt during 2010, and 11.9% (95% CI, -11.1% to 30.1%) for receipt during 2009/2008; point estimates were higher among Boostrix recipients than among Adacel recipients. Among Tdap recipients, increasing time since receipt was associated with increased risk, and receipt of Boostrix (vs Adacel) was associated with decreased risk of pertussis (adjusted IRR, 0.62 [95% CI, .52-.74]). Our results demonstrate waning immunity following vaccination with either Tdap brand. Boostrix was more effective than Adacel in preventing pertussis in our cohort, but these findings may not be generalizable to adolescent cohorts that received different diphtheria-tetanus-acellular pertussis vaccines (DTaP) during childhood and should be further examined in studies that include childhood DTaP history.

PIN10 - Recent Trends In Incidence Of Infant Pertussis Hospitalizations In The United States

Infants are at greatest risk for severe pertussis (~50% of infant cases require hospitalization). Recent surveillance indicates a resurgence of overall pertussis incidence in the US, but limited data exist on whether severe infantile cases are also resurging and the extent to which severe pertussis incidence in infants varies by sex and race. We therefore assessed recent US trends in overall and sex- and race-stratified incidence of infant pertussis-related hospitalizations. Data on pertussis-related hospitalizations (ICD-9-CM discharge codes 033.0, 033.8, 033.9, 484.3) from the 2000-2011 Nationwide Inpatient Sample (NIS) were retrospectively analyzed. Annual pertussis-related hospitalizations per 10,000 infants aged <12 months was estimated using NIS sampling weights and year-specific population denominators from US census data. Incidence of pertussis-related hospitalization was ~6/10,000 infants between 2000 and 2003 before increasing sharply in 2004 (9.0/10,000) and 2005 (13.8/10,000). Thereafter, incidence fell substantially (6.2, 4.1, and 4.2/10,000 in 2006, 2007, and 2008, respectively) before increasing again in 2009 and 2010 (5.9 and 7.8/10,000, respectively). Incidence declined again in 2011 (3.2/10,000). Incidence was similar between males and females, but substantial differences were observed by race. Incidence was highest in Hispanic infants, starting at 8.6/10,000 in 2000, peaking at 24.9/10,000 in 2005, and then falling to 4.3/10,000 in 2008 before another sharp increase to 14.7/10,000 in 2010. Incidence was lowest for white and Asian infants, reaching a 2005 peak of only 5.4 and 5.3/10,000, respectively. Infant pertussis hospitalizations peaked in 2005 before a sharp decline thereafter, possibly due to increased herd immunity conferred by the 2006 launch of universal adolescent Tdap vaccination. Incidence resurged again through 2010 before another decline in 2011, demonstrating for severe cases the documented cyclic pattern of peaks and nadirs for overall pertussis incidence. This analysis also highlights the need for increased focus on minorities in pertussis vaccination programs.

Prolonged Pertussis Outbreak in Ontario Originating in an Under-immunized Religious Community.

A prolonged pertussis outbreak began in Ontario in November 2011 in an under-immunized religious community and subsequently spread to the general population and a second religious community in the same region of the province. To compare the epidemiology in the religious communities to that of the general population within the affected jurisdictions. The analysis includes cases reported through the integrated Public Health Information System (iPHIS) between November 1, 2011 and April 15, 2013 that met the outbreak case definition. Health unit staff assessed whether cases were members of religious communities through case investigations and collected information on immunization status, treatment and outcomes. A total of 443 confirmed and probable outbreak cases were reported in 7 health units. The outbreak began in one religious community (138 cases), before spreading to the general population in the region (273 cases). A second under-immunized community within the region experienced 32 cases. Thirteen cases were hospitalized and no deaths were reported. Disease peaked earlier in the religious community; cases were significantly younger, more likely to be at high risk for pertussis and more likely to be unimmunized. Among the fully immunized general population, 51% of cases were between 10-14 years and with a median of 5.6 years since their last immunization. The epidemiology of pertussis in the under-immunized community is distinct from the general population. Transmission of pertussis to the general community is not unexpected during an outbreak; however, the proportion of cases up to date with immunization warrants further investigation.

Association Between Undervaccination With Diphtheria, Tetanus Toxoids, and Acellular Pertussis (DTaP) Vaccine and Risk of Pertussis Infection in Children 3 to 36 Months of Age

Undervaccination is an increasing trend that potentially places children and their communities at an increased risk for serious infectious diseases. To examine the association between undervaccination and pertussis in children 3 to 36 months of age. Matched case-control study with conditional logistic regression analysis. Eight managed care organizations of the Vaccine Safety Datalink between 2004 and 2010. Each laboratory-confirmed case of pertussis (72 patients) was matched to 4 randomly selected controls (for a total of 288 controls). The case patients were matched to controls by managed care organization site, sex, and age at the index date. The index date was defined as the date of pertussis diagnosis for the case patients. Undervaccination for the diphtheria, tetanus toxoids, and acellular pertussis (DTaP) vaccine. Undervaccination was defined as the number of doses of DTaP vaccine that was either missing or delayed by the index date. Case patients and controls could be undervaccinated by 0, 1, 2, 3, or 4 doses of DTaP vaccine. Children undervaccinated by 0 doses were considered age-appropriately vaccinated by the index date. Pertussis. Of the 72 case patients with pertussis, 12 (16.67%) were hospitalized, and 34 (47.22%) were undervaccinated for DTaP vaccine by the date of pertussis diagnosis. Of the 288 matched controls, 64 (22.22%) were undervaccinated for DTaP vaccine. Undervaccination was strongly associated with pertussis. Children undervaccinated for 3 or 4 doses of DTaP vaccine were 18.56 (95% CI, 4.92-69.95) and 28.38 (95% CI, 3.19-252.63) times more likely, respectively, to have received a diagnosis of pertussis than children who were age-appropriately vaccinated. Undervaccination with DTaP vaccine increases the risk of pertussis among children 3 to 36 months of age.

Reduced Risk of Pertussis in Whole-Cell Compared to Acellular Vaccine Recipients Is Not Supported When Data Are Stratified by Age

Reduced Risk of Pertussis in Whole-Cell Compared to Acellular Vaccine Recipients Is Not Supported When Data Are Stratified by Age

Religious Exemptions for Immunization and Risk of Pertussis in New York State, 2000–2011

The objective of this study was to describe rates of religious vaccination exemptions over time and the association with pertussis in New York State (NYS). Religious vaccination exemptions reported via school surveys of the NYS Department of Health from 2000 through 2011 were reviewed by county, and the changes were assessed against incidence rates of pertussis among children reported to the NYS Department of Health Communicable Disease Electronic Surveillance System. The overall annual state mean prevalence (± SD) of religious exemptions for ≥1 vaccines in 2000-2011 was 0.4% ± 0.08% and increased significantly from 0.23% in 2000 to 0.45% in 2011 (P = .001). The prevalence of religious exemptions varied greatly among counties and increased by >100% in 34 counties during the study period. Counties with mean exemption prevalence rates of ≥1% reported a higher incidence of pertussis, 33 per 100 000 than counties with lower exemption rates, 20 per 100 000, P < .001. In addition, the risk of pertussis among vaccinated children living in counties with high exemption rate increased with increase of exemption rate among exempted children (P = .008). The prevalence of religious exemptions varies among NYS counties and increased during the past decade. Counties with higher exemption rates had higher rates of reported pertussis among exempted and vaccinated children when compared with the low-exemption counties. More studies are needed to characterize differences in the process of obtaining exemptions among NYS schools, and education is needed regarding the risks to the community of individuals opting out from recommended vaccinations.

Should acellular pertussis vaccine be recommended to healthcare professionals?

The aim of this study was to describe recent changes in the epidemiology of pertussis and existing policies regarding recommended and mandatory occupational vaccinations for healthcare professionals (HCPs). The authors carried out an extensive review of references on the PubMed and SciELO databases and the official sites of the World Health Organization, Pan American Health Organization, Centers for Disease Control and Prevention, and Brazilian Ministry of Health, using the keywords pertussis, vaccines and healthcare professionals. Vaccination against pertussis is recommended for HCPs in the United States, Canada, nine European countries, Australia, Hong Kong, Singapore, Costa Rica, Argentina and Uruguay, and in some countries it is compulsory. In Brazil, only one publication discussing the risk of pertussis among HCPs was found. Considering the reemergence of pertussis and the great number of associated hospitalizations and deaths registered in 2011, it is necessary to review public policies regarding HCP pertussis vaccination, particularly among workers in frequent contact with young babies.

Should acellular pertussis vaccine be recommended to healthcare professionals?

The aim of this study was to describe recent changes in the epidemiology of pertussis and existing policies regarding recommended and mandatory occupational vaccinations for healthcare professionals (HCPs). The authors carried out an extensive review of references on the PubMed and SciELO databases and the official sites of the World Health Organization, Pan American Health Organization, Centers for Disease Control and Prevention, and Brazilian Ministry of Health, using the keywords pertussis, vaccines and healthcare professionals. Vaccination against pertussis is recommended for HCPs in the United States, Canada, nine European countries, Australia, Hong Kong, Singapore, Costa Rica, Argentina and Uruguay, and in some countries it is compulsory. In Brazil, only one publication discussing the risk of pertussis among HCPs was found. Considering the reemergence of pertussis and the great number of associated hospitalizations and deaths registered in 2011, it is necessary to review public policies regarding HCP pertussis vaccination, particularly among workers in frequent contact with young babies.

Religious Exemptions for Immunization and Risk of Pertussis in New York State, 2000-2011

Religious Exemptions for Immunization and Risk of Pertussis in New York State, 2000-2011

Comparative Effectiveness of Acellular Versus Whole-Cell Pertussis Vaccines in Teenagers

During the 1990s, the United States switched from combined diphtheria, tetanus toxoids, whole-cell pertussis (DTwP) vaccines to combined acellular pertussis (DTaP) vaccines because of safety concerns. After a 2010-2011 pertussis outbreak, we sought to evaluate whether disease risk in 10 to 17 year olds differed between those who previously received DTwP from those who received DTaP. A case-control study among individuals born from 1994 to 1999 who received 4 pertussis-containing vaccines during the first 2 years of life at Kaiser Permanente Northern California (KPNC). We separately compared pertussis polymerase chain reaction (PCR)-positive cases with PCR-negative and KPNC-matched controls. We assessed risk of pertussis relative to vaccine type in early childhood (4 DTwPs, mixed DTwP/DTaP, or 4 DTaPs) by using conditional logistic regression stratified for calendar time and adjusted for gender, race, medical clinic, and receipt of reduced antigen content acellular pertussis (Tdap) vaccine. We compared 138 PCR-positive cases with 899 PCR-negative and 54 339 KPNC-matched controls. Teenagers who had received 4 DTwPs were much less likely to be pertussis PCR-positive than those who had received 4 DTaPs (odds ratio 5.63, 95% confidence interval 2.55-12.46) or mixed DTwP/DTaP vaccines (odds ratio 3.77, 95% confidence interval 1.57-9.07). Decreasing number of DTwP doses was significantly associated with increased pertussis risk (P < .0001). Teenagers who received DTwP vaccines in childhood were more protected during a pertussis outbreak than were those who received DTaP vaccines.