Global Pertussis Initiative Research Articles

The current state of pertussis vaccination in pregnancy around the world, with recommendations for improved care: Consensus statements from the Global Pertussis Initiative.

Bordetella pertussis, which causes a respiratory disease known as pertussis ("whooping cough") remains an important global challenge, with the incidence in pertussis cases increasing in recent years. Newborns and infants are at increased risk for severe morbidity and mortality from this bacterium. Vaccination in pregnancy has become an important strategy to both passively transfer immunity as well as prevent infection in pregnant persons, who are a major source of newborn infection, thus attempting to decrease the impact of this serious disease. It is considered safe for the pregnant person, the developing fetus, and the infant, and during the first 3 months of life it has been shown to be highly effective in preventing pertussis. There are a variety of strategies, recommendations, and adherence rates associated with pertussis vaccination in pregnancy around the world. We summarize the 2021 Global Pertussis Initiative Annual Meeting that reviewed the current global status of pertussis vaccination in pregnancy and remaining medical and scientific questions, with a focus on vaccination challenges and strategies for obstetric and gynecologic healthcare providers.

Vaccination against Pertussis in the era of acellular and whole-cell vaccines

Pertussis in a highly infectious respiratory disease, and even though vaccination has been globally implemented since the 1940s, we are far from elimination, and even still suffering from many outbreaks throughout the world. This comprehensive review is tailored primarily for clinicians and healthcare practitioners, aiming to deepen their insights into the evolving dynamics of Pertussis over time since the first whole-cell Pertussis vaccine was started. It delves into the high reactogenicity and alleged severe neurologic effects, which were later conclusively disproven. The ensuing repercussions of these early challenges manifested in multiple outbreaks, compelling the scientific community to respond proactively. This led to the development and subsequent implementation of acellular Pertussis vaccines, marked by an improved safety profile. Moreover, the exclusive adoption of acellular Pertussis vaccines for widespread immunization in certain countries resulted in a notable surge in Pertussis cases. Subsequent investigations, conducted through both animal models and epidemiological studies, elucidated that acellular Pertussis vaccines exhibited a considerably diminished mucosal immunity. Consequently, nasopharyngeal carriage showed minimal reduction, leading to a substantial decline in indirect or herd immunity when compared to whole-cell Pertussis vaccines. Conversely, numerous developing countries presently incorporate whole-cell Pertussis vaccines either independently or in conjunction with acellular formulations. In light of this, precise recommendations must be systematically addressed to cultivate a more unified and pragmatic landscape for immunization strategies. These recommendations should be rooted in the latest scientific data and aligned with the guidelines articulated by both the World Health Organization and the Global Pertussis Initiative. This concerted approach aims to optimize immunization practices on a global scale, fostering a harmonized and evidence-based framework for combating Pertussis. Relevant and updated issues concerning maternal, adolescent and adult vaccination are addressed, as well as the ongoing pipeline of new intramuscular and mucosal vaccines, and finally emphasizing the continuous need for improved surveillance and pharmacovigilance systems.

Pertussis in India: Past, Present, and Future.

While vaccines have markedly reduced the incidence of pertussis, a resurgence has occurred in many countries. Until recently, pertussis has not been recognized as an important public health challenge in India due to its successful infant immunization program. However, India still accounts for a large proportion of the world's cases, and increasing reports of pertussis in other countries and in neonates have regenerated interest in pertussis among Indian authorities. The Global Pertussis Initiative (GPI) Annual Meeting was held virtually in October 2020, in part, to gain a better understanding of the epidemiology and disease burden of pertussis and to explore opportunities to improve its prevention in India. There was a consensus that pertussis cases are being underestimated in India due to multiple factors, such as a reliance on passive surveillance and diagnostic challenges. India offers both whole-cell pertussis and acellular pertussis vaccines, but vaccine coverage is inconsistent across regions due to differences in vaccine availability, access to health care, and regional administrative challenges. This report summarizes the outcomes and considers the key clinical implications of this meeting. The GPI agreed that active surveillance of pertussis in India would be optimal and recommended several studies, including serosurveillance among women of reproductive age to assess the prevalence of recent pertussis infection and to enable policy changes that will enhance the rational use of acellular and whole-cell vaccines. It also recommended engagement with nongovernmental organizations in order to encourage pregnancy immunization in the public sector. To achieve effective control of pertussis in the future, the GPI recognizes there are opportunities to characterize the burden of pertussis in India appropriately and increase vaccination coverage in multiple age groups.

Vaccination in Pregnancy against Pertussis: A Consensus Statement on Behalf of the Global Pertussis Initiative.

Infants are at high risk for severe morbidity and mortality from pertussis disease during early infancy. Vaccination against pertussis in pregnancy has emerged as the ideal strategy to protect infants during these early, vulnerable, first months of life. On 30 November and 1 December 2021, the Global Pertussis Initiative held a meeting that aimed to discuss and review the most up-to-date scientific literature supporting vaccination against pertussis in pregnancy and outstanding scientific questions. Herein, we review the current and historically published literature and summarize the findings as consensus statements on vaccination against pertussis in pregnancy on behalf of the Global Pertussis Initiative.

Pertussis in Asia: Recent country-specific data and recommendations

The Global Pertussis Initiative (GPI) Roundtable Meeting held in 2019, which preceded the COVID-19 pandemic, focused on the incidence, surveillance, and immunization practices for pertussis in the Asian region. Participants from China, India, Indonesia, Malaysia, Pakistan, Philippines, South Korea, Taiwan, and Thailand presented country-specific information on pertussis prevalence, diagnosis, surveillance, vaccine administration and schedules, maternal and neonatal disease rates, and policies and practice of vaccination during pregnancy. In recent years, many Asian countries have seen an increase in pertussis cases, although underreporting of the disease is a concern. Currently, most Asian countries have only passive surveillance for pertussis in place. There is a need for improved surveillance to determine the disease burden and justify vaccination policies and recommendations, such as essential vaccination, boosters, and vaccination during pregnancy. Better awareness of the disease in adolescents and adults is necessary, and infant and childhood vaccination schedules need to be improved in many countries. Differences between private versus public sector vaccination schedules and between whole-cell and acellular pertussis vaccines should continue to be examined. It can be anticipated that unmet needs in the prevention and management of pertussis will continue as the COVID-19 pandemic evolves and that key recommendations highlighted in this meeting report will be of ongoing importance.

Expert consensus on the China Pertussis Initiative

Some countries with high coverage of diphtheria, tetanus and pertussis combined vaccines have experienced pertussis epidemics and/or local outbreaks since 1980s. This phenomenon is called "pertussis resurgence". In recent years, pertussis epidemics in several provinces of China have resurged dramatically, arousing great concern from all parties. By referring the working model of the Global Pertussis Initiative, the Chinese Preventive Medicine Association has organized and launched the China Pertussis Initiative. A group of experts in this field has analyzed data of current pertussis in China and identified problems posed by the disease. This expert consensus was completed based on the discussions of the latest national and international research progress, epidemiological trends and immunization strategies of pertussis, with special aims to provide guidance for the surveillance, prevention and control of pertussis in China.

Expert consensus on the China Pertussis Initiative

Some countries with high coverage of diphtheria, tetanus and pertussis combined vaccines have experienced pertussis epidemics and/or local outbreaks since 1980s. This phenomenon is called "pertussis resurgence". In recent years, pertussis epidemics in several provinces of China have resurged dramatically, arousing great concern from all parties. By referring the working model of the Global Pertussis Initiative, the Chinese Preventive Medicine Association has organized and launched the China Pertussis Initiative. A group of experts in this field has analyzed data of current pertussis in China and identified problems posed by the disease. This expert consensus was completed based on the discussions of the latest national and international research progeress, epidemiological trends and immunization strategies of pertussis, with special aims to provide guidance for the surveillance, prevention and control of pertussis in China.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in Africa.

The Global Pertussis Initiative recommends diphtheria–tetanus–pertussis (DTP3) vaccination of infants aged < 1 year for all African countries, and recommends the vaccination of pregnant women as a primary prevention strategy. However, the role of older children and adults in the transmission of pertussis in Africa is not clear. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in Africa. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible because of the mix of methodologies used.Studies from North Africa (Morocco, Tunisia, and Algeria) reported that although DTP4 vaccine coverage is high, severe pertussis-related complications persist in young children, vaccine-acquired immunity wanes in adolescents, and household contacts are important transmitters of infection. A serosurvey in Gambia showed that 6% of the general population had pertussis antibody levels suggesting recent infection, and studies from Senegal showed that pertussis infection was endemic despite high DTP3 coverage. During a pertussis outbreak in Ethiopia, the case fatality rate was 3.7% overall, and 6.3% among children aged 5–9 years. In a case-surveillance study in South Africa, the incidence of pertussis among hospitalized children was 526/100,000, and infection rates were higher in HIV-exposed and -infected children compared with uninfected children. In conclusion, the highest burden of pertussis in Africa is among infants, and surveillance is lacking in many African countries meaning that the burden of pertussis among infants and infection rates among older children and adults are not well reported, and likely underestimated.Electronic supplementary materialThe online version of this article (doi:10.1007/s40121-021-00442-6) contains supplementary material, which is available to authorized users.

Diagnostic limitations of clinical case definitions of pertussis in infants and children with severe lower respiratory tract infection.

Diagnosis of pertussis is challenging especially in infants. Most low and middle-income countries (LMIC) lack resources for laboratory confirmation, relying largely on clinical diagnosis alone for both case management and surveillance. This necessitates robust clinical case definitions. This study assesses the accuracy of clinical case definitions with and without lymphocytosis in diagnosing pertussis in children with severe lower respiratory tract infection (LRTI) in a LMIC setting. Children hospitalized with severe LRTI in a South African hospital were prospectively enrolled and evaluated for pertussis using PCR on respiratory samples. Clinical signs and differential white cell counts were recorded. Sensitivity and specificity of pertussis clinical diagnosis using WHO and Global Pertussis Initiative (GPI) criteria; and with addition of lymphocytosis were assessed with PCR as the reference standard. 458 children <10 years were enrolled. Bordetella pertussis infection was confirmed in 32 (7.0%). For WHO criteria, sensitivity was 78.1% (95% CI 60.7-89.2%) and specificity 15.5% (95% CI 12.4-19.3%); for GPI sensitivity was 34.4% (95% CI 20.1-52.1) and specificity 64.8% (95% CI 60.1-69.2%). Area under the curve (AUC) on receiver operating character (ROC) analysis was 0.58 (95% CI 0.46-0.70 for WHO criteria, and 0.72 (95% CI 0.56-0.88) for GPI with highest likelihood ratios of 5.33 and 4.42 respectively. Diagnostic accuracy was highest between five and seven days of symptoms for both criteria. Lymphocytosis had sensitivity of 31.3% (95% CI 17.5-49.3%) and specificity of 70.7% (95% CI 66.1-74.8%) and showed a marginal impact on improving clinical criteria. Clinical criteria lack accuracy for diagnosis and surveillance of pertussis. Non-outbreak settings should consider shorter durations in clinical criteria. New recommendations still fall short of what is required for a viable clinical screening test which means the need to improve access to laboratory diagnostic support remains crucial.

Pertussis in Latin America: Recent epidemiological data presented at the 2017 Global Pertussis Initiative meeting

The Global Pertussis Initiative (GPI) is an expert scientific forum that publishes consensus recommendations for pertussis monitoring, prevention, and treatment across many regions of the world. Here, we report on the regional 2017 GPI meeting on the Americas, focusing on Latin America. Information on current pertussis epidemiology, surveillance, vaccine strategies, diagnostic capabilities, disease awareness, and major local obstacles was presented by researchers from Argentina, Brazil, Colombia, Costa Rica, El Salvador, Mexico, Peru, Puerto Rico, Uruguay, and Venezuela. Pertussis outbreaks have occurred during the last decade in the majority of participant countries and have been followed by improvements in surveillance. In the countries that introduced maternal immunization during pregnancy, a reduction in the infant case fatality rate has been detected. All countries need to maintain and improve pertussis surveillance to reach primary vaccination coverage >90%. Moreover, countries without maternal immunization programs should strongly consider them.

Seasonal distribution of pertussis

Introduction/Objective. The seasonality of pertussis is not exactly determined. The aim of this study was to describe the seasonal distribution of pertussis in the South Backa District of Vojvodina, Serbia, during four consecutive years. Methods. Data for this observational study were obtained from outpatient and inpatient health care facilities in the South Backa District from January 1, 2013 to December 31, 2016. We evaluated the seasonal distribution of pertussis among the patients who fulfilled one or more criteria of clinical case definitions of pertussis proposed by the Global Pertussis Initiative. Laboratory confirmations of pertussis were obtained using real-time polymerase chain reaction or ELISA serology tests. Results. A total of 1,043 participants were included, of which 28.8% were laboratory-confirmed pertussis, with the highest prevalence of laboratory confirmation (66%) in June 2016. Observed by seasons (spring, summer, fall, and winter), there was no significant difference in the average number of testing patients or laboratory-confirmed pertussis during the study period. The average number of laboratory-confirmed cases was significantly higher in patients 0?6 years of age (p = 0.020), and with a borderline of significance in the 7?10 years age group (p = 0.049) in summer, compared to other three seasons during four consecutive years. Conclusions. With the increased physician awareness after implementation of the new clinical case definitions, pertussis was recognized throughout all four consecutive years without a clear seasonal pattern of occurrence in our area. Paralleling increase of laboratory-confirmed pertussis during summer months in comparison with other seasons in younger and older age groups suggests a possible transmission within families.

Evaluation of the diagnostic utility of the new clinical case definition of pertussis - experience from sentinel and hospital-based pertussis surveillance

Introduction/Objective. Global surveillance systems use different clinical case definitions of pertussis. The aim of this study was to identify sign and symptom combinations with best relation with laboratory confirmed pertussis. Methods. A one-year prospective observational study, proposed by the Global Pertussis Initiative (GPI) for three age groups (0?3 months, four months to nine years, and ? 10 years) was performed in Novi Sad to evaluate the performance of the clinical case definition of pertussis. Laboratory confirmation of B. pertussis infection was obtained using the DNA polymerase chain reaction (PCR) or ELISA serology tests. Results. From October 1, 2013 to September 30, 2014, 103 (32.3%) out of 319 participants with suspected pertussis had laboratory-confirmed pertussis. Combined whooping, post-tussive emesis, and worsening of symptoms at night was the best predictor of pertussis in outpatients aged four months to nine years (positive likelihood ratio (LR+) 11.6), while among inpatients of the same age group it was apnoea (LR+ 13.5). The LR+ in outpatients aged ?10 years for combinations of apnoea and post-tussive emesis, or a combination of whooping and sweating episodes between paroxysms and post-tussive emesis was 16.8, while among in-patients LR+ was &lt; 2.3 for all combinations in the same age group. Conclusions. The GPI case definitions for pertussis are good predictors for laboratory-confirmed pertussis and are useful for the purpose of pertussis surveillance.

Performance of the new clinical case definitions of pertussis in pertussis suspected infection and other diagnoses similar to pertussis.

BackgroundIn an effort to improve the pertussis diagnosis, the Global Pertussis Initiative (GPI) proposed an algorithm of the signs/symptoms of pertussis for three age groups: 0–3 months, 4 months to 9 years, and ≥10 years of age.MethodsWe evaluated the accuracy of the clinical case definitions for pertussis proposed by the GPI using laboratory-confirmed pertussis as a reference standard for four groups: clinically suspected pertussis without comorbidity; asthma exacerbation; allergic constitution, and other diagnoses (bronchitis, bronchiolitis, laryngitis, and tracheitis). We included only patients who fulfilled one or more criteria of clinical case definitions for the age groups (0–3 months, 4 months–9 years, and ≥10 years of age).The data for this prospective epidemiological study were collected between 1st January 2013–31st December 2016 at the outpatients and inpatients health care settings in the South Bačka District of Autonomous Province of Vojvodina, Serbia. We evaluated accuracy of the certain sign and symptom combinations of GPI case definitions based on their sensitivity, specificity, and likelihood ratios.ResultsA total of 1043 participants were included, with 306 (29.3%) laboratory-confirmed pertussis cases. In patients aged 0–3 months, whoop and apnoea associated with laboratory confirmation of pertussis. In patients aged 4 months-9 years with a pertussis suspicion infection or with one of the other diagnoses, the highest accuracy was found for whoop combined with apnoea or post-tussive emesis. In patients aged 10 years and older, several different sign and symptom combinations were associated with an increased risk of pertussis among all enrolment diagnoses. There were fewer hospitalizations among the fully vaccinated children than in partly or unvaccinated children aged 4 months to 6 years (20.7% vs. 60.0%, p = 0.017).ConclusionsThe numerous sign and symptom combinations in the observed case definitions were good predictors for laboratory-confirmed pertussis among all enrolment diagnoses, therefore suggesting the necessity for increased awareness of possibility for pertussis in patients with certain pertussis-like medical conditions.

Pertussis in children under the age of 10

Introduction/Objective. Pertussis is a vaccine-preventable disease that causes a large number of cases and hospitalizations worldwide. The aim of this study was to determine predictors of hospitalization in cases of pertussis among children under 10 years of age in the South Backa District of Vojvodina Province, Serbia. Methods. Data for this observational study were obtained from inpatient and outpatient healthcare facilities in the South Backa District from January 1, 2013 to December 31, 2016. We evaluated predictors of hospitalization among the patients who fulfilled the criteria of case definitions of pertussis proposed by the Global Pertussis Initiative. Pertussis was confirmed by DNA polymerase chain reaction or ELISA serology tests. Results. Out of 122 laboratory-confirmed pertussis cases, 43 (35.2%) were hospitalized. Apnea and pneumonia were associated with hospitalization, and all six hospitalized patients aged 0?3 months had cyanosis. Apnea was a good predictor of hospitalization among children with any duration of cough (p &lt; 0.05). Among children with a cough that lasted longer than 14 days, post-tussive emesis or pneumonia or contact with a person who had a prolonged cough were associated with hospitalization (p = 0.035, p = 0.042, and p = 0.046, respectively). There were fewer hospitalizations in properly vaccinated cases than in partly or non-vaccinated cases between two months and four years of age (p &lt; 0.008). Conclusions. Among the pertussis cases under 10 years of age, apnea, pneumonia, and cyanosis were factors associated with hospitalization. Immunization against pertussis corresponding to age reduces the disease severity and hospitalizations in children from two months to four years of age.

Pertussis Vaccination Among Childcare Center Staff, Administrators, and Parents: Uptake, Policies, and Beliefs.

Introduction Little is known about childcare staff's and parents' uptake of and attitudes towards pertussis vaccine. Methods Questionnaires were distributed to St. Louis parents and childcare staff in fall, 2014. Parents versus staff and vaccinated versus unvaccinated individuals' beliefs regarding pertussis vaccine were compared using chi square tests. Multivariate logistic regressions were run to develop predictive models for staff's and parents' vaccine uptake. Results Overall, 351 parents and staff from 23 agencies participated (response rate = 32%). Parents were more likely than staff to have received pertussis vaccine (66.5 vs. 45.8%, X 2 = 12.5, p < .001). Predictors for staff vaccination included willingness to get vaccinated even if there was a cost (OR 6.6; CI 1.8-24.6; p < .01), awareness of vaccination recommendations (OR 5.2; CI 1.2-22.8; p < .05), and healthcare provider recommendation (OR 4.2; CI 1.2-15.1; p < .05). Parents' predictors of vaccination included perceived importance of vaccination (OR 9.9; CI 4.1-23.8; p < .001), healthcare provider recommendation (OR 4.6; CI 1.7-12.6; p < .01), believing vaccination is effective (OR 4.4; CI 1.1-18.0; p < .05), and knowing where to get vaccine (OR 3.5; CI 1.5-8.1; p < .01). Among unvaccinated staff (n = 52), 74.5% (n = 38) and 70.0% (n = 35) would receive pertussis vaccine if it were offered free of charge and onsite, respectively. Conclusions for Practice Childcare staff's and parents' pertussis vaccine uptake was higher than overall U.S. rates, though significantly lower than the Global Pertussis Initiative target. Implementing an education campaign and providing free vaccine on-site are likely to result in increased vaccine uptake.

Pertussis incidence rates in Novi Sad (Serbia) before and during improved surveillance

Introduction/Objective. The Global Pertussis Initiative (GPI) proposed clinical case definitions for pertussis diagnosis in three different age cohorts in order to improve surveillance of pertussis especially in older children, adolescents, and adults. The main goal of this research was to compare the burden of pertussis in the city of Novi Sad before and after the introduction of improved surveillance using the GPI clinical case definitions of pertussis. Methods. Baseline data on pertussis were obtained from routine (non-sentinel) reporting before improved surveillance was introduced. From September 16, 2012, clinical case definitions proposed by GPI were applied within improved (sentinel and hospital) surveillance, while surveillance clinical case definitions were not introduced within non-sentinel. To confirm the suspected diagnosis, sampling of nasopharyngeal swab and/or blood was obtained from all cases. The choice of laboratory method (PCR or ELISA) depended on the duration of coughing and the age of the patients. Data were statistically processed by SPSS Statistics, version 22. Results. During the 12-year period before the introduction of improved surveillance, only two clinical pertussis cases were registered. In contrast, during the two-year period of improved surveillance, a total of 14 (season 2012/13) and 146 (season 2013/2014) confirmed pertussis cases were reported. Significant differences were determined in distribution of pertussis according to the type of surveillance and the level of health care. Conclusion. Introduction of clinical case definitions proposed by GPI improved the quality of surveillance and enabled an insight in the distribution of pertussis in all age groups and at all levels of health care.

Intention to Accept Pertussis Vaccination for Cocooning: A Qualitative Study of the Determinants.

ContextSeveral countries have reported a resurgence of pertussis in the last decades. This puts infants (especially <6 months) at risk of severe complications, because they are too young to be fully protected by vaccination. The global pertussis initiative has proposed pertussis vaccination of young infants’ close contacts, in order to reduce pertussis transmission and the burden of the disease on infants. Our aim is to explore the perceived determinants (barriers and facilitators) of intention to accept vaccination among the possible target groups of pertussis vaccination for cocooning. Consideration of these determinants is necessary to optimise the uptake of the vaccination.MethodsWe conducted 13 focus groups and six individual semi-structured interviews with members of possible target groups for pertussis cocooning (i.e. parents, maternity assistants, midwives, and paediatric nurses) in the Netherlands. Here, both maternal pertussis vaccination as well as pertussis cocooning has not been implemented. The topic list was based on a literature review and a barrier framework. All interviews were transcribed verbatim and two researchers performed thematic content analysis.FindingsThe participants’ risk perception, outcome expectations, general vaccination beliefs, moral norms, opinion of others, perceived autonomy, anticipated regret, decisional uncertainty, and perceived organisational barriers were all factors that influenced the intention to accept pertussis vaccination for cocooning.DiscussionThis study has identified nine perceived determinants that influence the intention to accept pertussis cocooning vaccination. We add the following determinants to the literature: perceived cost-effectiveness (as a concept of outcome expectations), justice (as a concept of moral norms), anticipated regret, and decisional uncertainty. We recommend considering these determinants in vaccination programmes for pertussis cocooning vaccination. Experience, information and trust emerged as predominant themes within these determinants. These themes require particular attention in future research on vaccination acceptance, especially with regard to their role in use and implementation in policy and practice.

Clinical Characteristics and Factors Associated With Measles Transmission in California

Background. Since 2014, California has experienced an increase in measles cases including a large outbreak associated with a theme park. We describe factors associated with measles transmission and clinical features of cases with ≥2 doses of MCV. Method. Measles cases reported to the California Department of Public Health (CDPH) from January 1, 2000–July 1, 2015 were reviewed. Measles transmitters were defined as patients who transmitted measles to one or more persons based on epidemiologic linkage, supported by appropriate timing and genotype data, when available. Ambiguous exposure situations were excluded. Multiple logistic regression was used to identify factors associated with measles transmission, including measles clinical features (cough, coryza, conjunctivitis, fever), vaccination status and age. Fisher's exact test was used in a sub-analysis of clinical features among those with verified immunization status. Result. Three hundred ninety-seven measles cases were reported to CDPH. In the multiple logistic regression model, coughing increased odds of transmission (OR: 3.3; 95% CI: 1.1–9.7), whereas age 2 doses of MCV. In a sub-analysis of those with documented vaccination status, cases with ≥2 MCV doses less frequently reported cough (p < 0.0001), coryza (p < 0.0001), conjunctivitis (p < 0.0001), fever (p < 0.01) and hospitalization (p = 0.03) versus unvaccinated cases or those with one dose. The median time since vaccination for cases with ≥2 MCV doses was 17 years (range: 6–39 years). Three patients with ≥2 MCV doses transmitted measles to close contacts; all reported cough while none of the patients with ≥2 MCV doses but without cough transmitted. Conclusion. Clinical and demographic features may be used to identify cases at high risk of transmitting measles and to prioritize investigation of their contacts. Prior vaccination appears to attenuate measles illness and reduce transmission. While some cases with ≥2 MCV doses are primary vaccine failures, the role of waning immunity among vaccinated people in measles outbreaks should be considered. Disclosures. J. Zipprich, Pfizer: Spouse works at Pfizer, Salary; J. D. Cherry, Global Pertussis Initiative: Member, Honoraria for participating and speaking at many GPI meetings since 2000. Sanofipasteur: Speaker's Bureau, Speaker honorarium

Strategies to decrease pertussis transmission to infants.

The Global Pertussis Initiative (GPI) is an expert scientific forum addressing the worldwide burden of pertussis, which remains a serious health issue, especially in infants. This age cohort is at risk for developing pertussis by transmission from those in close proximity. Risk is increased in infants aged 0 to 6 weeks, as they are too young to be vaccinated. Older infants are at risk when their vaccination schedules are incomplete. Infants also bear the greatest disease burden owing to their high risk for pertussis-related complications and death; therefore, protecting them is a high priority. Two vaccine strategies have been proposed to protect infants. The first involves vaccinating pregnant women, which directly protects through the passive transfer of pertussis antibodies. The second strategy, cocooning, involves vaccinating parents, caregivers, and other close contacts, which indirectly protects infants from transmission by preventing disease in those in close proximity. The goal of this review was to present and discuss evidence on these 2 strategies. Based on available data, the GPI recommends vaccination during pregnancy as the primary strategy, given its efficacy, safety, and logistic advantages over a cocoon approach. If vaccination during pregnancy is not feasible, then all individuals having close contact with infants <6 months old should be immunized consistent with local health authority guidelines. These efforts are anticipated to minimize pertussis transmission to vulnerable infants, although real-world effectiveness data are limited. Countries should educate lay and medical communities on pertussis and introduce robust surveillance practices while implementing these protective strategies.

Tdap in every pregnancy: circling the wagons around the newborn.

The resurgence of pertussis in the United States and many other countries in the world has become a major problem, with no immediate solution in sight. In 2014, the >10 000 reported cases of pertussis in California surpassed a recent previous record set in 2010 and all other records in the postvaccine era. The national experience mimics that of California, with rising numbers of cases widespread over the last 4 years. Sadly, the rising disease rate is accompanied by an increase in deaths from pertussis, almost exclusively in young infants. Why is this happening? We have learned that the immunity induced by acellular pertussis vaccines, the only type of vaccine used in the United States since the late 1990s, is not durable and wanes rapidly over just a few years. No sooner is 1 cohort of children protected from pertussis through immunization than another, older, cohort becomes susceptible again. We merely are treading water in our efforts to control pertussis with currently available vaccines. As well outlined in the Global Pertussis Initiative review and position statement by Forsyth et al1 in this issue of Pediatrics , we must circle the wagons around young infants. Very young infants suffer the greatest morbidity and almost exclusively the mortality related to pertussis, before they can be immunized. Couple this with an inability to … Address correspondence to Mark H. Sawyer, MD, 3020 Children’s Way, MC 5124, San Diego, CA 92123. E-mail: mhsawyer{at}ucsd.edu